WO2024005270A1 - Hydrogen generator - Google Patents

Hydrogen generator Download PDF

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WO2024005270A1
WO2024005270A1 PCT/KR2022/016118 KR2022016118W WO2024005270A1 WO 2024005270 A1 WO2024005270 A1 WO 2024005270A1 KR 2022016118 W KR2022016118 W KR 2022016118W WO 2024005270 A1 WO2024005270 A1 WO 2024005270A1
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electrode
electron transfer
generation device
hydrogen generation
lignin
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PCT/KR2022/016118
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French (fr)
Korean (ko)
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류정기
최유리
장성연
이상학
장지욱
메흐로트라라쉬미
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울산과학기술원
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Publication of WO2024005270A1 publication Critical patent/WO2024005270A1/en

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    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
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    • C25B1/02—Hydrogen or oxygen
    • C25B1/04—Hydrogen or oxygen by electrolysis of water
    • C—CHEMISTRY; METALLURGY
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    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/50—Processes
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    • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
    • C25B11/052—Electrodes comprising one or more electrocatalytic coatings on a substrate
    • C25B11/053—Electrodes comprising one or more electrocatalytic coatings on a substrate characterised by multilayer electrocatalytic coatings
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    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
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    • C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
    • C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
    • C25B11/075—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound
    • C25B11/077—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound the compound being a non-noble metal oxide
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    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
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    • C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
    • C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
    • C25B11/075—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound
    • C25B11/077—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound the compound being a non-noble metal oxide
    • C25B11/0773—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound the compound being a non-noble metal oxide of the perovskite type
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
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    • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
    • C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
    • C25B11/075—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound
    • C25B11/085—Organic compound
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    • C25B11/075—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound
    • C25B11/087—Photocatalytic compound
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    • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
    • C25B9/50—Cells or assemblies of cells comprising photoelectrodes; Assemblies of constructional parts thereof
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K30/00—Organic devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K30/00—Organic devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation
    • H10K30/10—Organic devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation comprising heterojunctions between organic semiconductors and inorganic semiconductors
    • H—ELECTRICITY
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    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K30/00—Organic devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation
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    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
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    • H10K30/80—Constructional details
    • H10K30/88—Passivation; Containers; Encapsulations

Definitions

  • the present invention relates to a hydrogen generation device, and more specifically to a bias-free hydrogen generation device using the depolymerization reaction of lignocellulose.
  • the purpose of the present invention is to provide a hydrogen generation device with high solar heat-hydrogen production efficiency.
  • a hydrogen generation device includes a first region and a second region separated by a semi-permeable membrane, a first electrode provided in the first region, and electrically connected to the first electrode and the second region. It includes a second electrode provided in, a depolymerization portion separated from the second region, and an electron transfer mediator provided in the first region and the depolymerization portion.
  • the electron transfer mediator decomposes lignocellulose in the depolymerization section and is simultaneously reduced and oxidized at the first electrode in the first region, and protons are reduced with electrons generated from the oxidation at the second electrode.
  • the lignocellulose is a combination of cellulose, hemicellulose, and lignin in a non-separated state.
  • the electron transfer mediator when the electron transfer mediator reacts with the cellulose, hemicellulose, and lignin, the lignin may be selectively decomposed.
  • by-products include vanillin, aceto vanillon, guaiacol, syringol, syringyl aldehyde, methyl syringol, phenyl acetone, and organic acids. At least one can be created.
  • the second electrode may be a perovskite-based photocathode.
  • the second electrode includes a solar cell unit, wherein the solar cell unit includes: a first sub-electrode, a photoreactive layer provided on the first sub-electrode, and a photoreactive layer provided on the photoreactive layer. It includes 2 sub-electrodes, and the photoreactive layer may include perovskite.
  • the second electrode further includes at least one of a hole transport layer provided between the first sub-electrode and the light absorption layer, and an electron transport layer provided between the light absorption layer and the second sub-electrode. can do.
  • a passivation layer provided between the light absorption layer and the electron transport layer may be further included.
  • the present invention further includes an encapsulation provided outside the solar cell unit to protect the solar cell unit, wherein the encapsulation unit includes: a first metal film provided on the second sub-electrode, and the first metal film provided on the second sub-electrode. 1 May include an external metal film provided on the metal film.
  • the first metal layer may include fields metal, and the external metal layer may include Ti or Ti-Pt.
  • a sealant may be included surrounding at least a portion of the outer surface of the second electrode.
  • the hydrogen generation device decomposes the lignocellulose, depending on the presence or absence of sunlight, the electron transfer mediator is reduced, and the reduced electron transfer mediator is oxidized to generate hydrogen. It may be driven in at least one of a mode and a second mode in which hydrogen is generated by absorbing the sunlight.
  • the first mode may correspond to a night when sunlight is provided to the second electrode, and the second mode may correspond to a day when the sunlight is provided to the second electrode.
  • the hydrogen generation device may be bias-free.
  • the hydrogen generation device may be free of oxygen generation.
  • the electron transfer mediator may be polyoxometalate. In one embodiment of the present invention, the electron transfer mediator may be phosphomolybdic acid.
  • the present invention includes a method of producing hydrogen using the hydrogen generating device, the method of producing hydrogen comprising the steps of oxidizing an electron transfer mediator at a first electrode to obtain an oxidized electron transfer mediator, the oxidized electron transfer mediator reducing a proton with an electron generated from the oxidation at a second electrode to obtain hydrogen.
  • the step of reducing the electron transfer mediator is a step of transferring electrons generated in the process of selectively decomposing lignocellulosic biomass to the electron transfer mediator.
  • biomass can be selectively decomposed at low temperature through an electron transfer mediator.
  • aromatic/aliphatic high value-added compounds can be produced by selectively decomposing lignin from lignocellulose while maintaining the properties of polysaccharides, and the residual polysaccharides can be utilized in existing biorefineries.
  • electrons can be effectively extracted from biomass, making efficient hydrogen production possible.
  • FIG. 1A is a diagram conceptually showing a hydrogen generation device according to an embodiment of the present invention that implements the above contents
  • FIG. 1B is a cross-sectional view conceptually showing the first electrode in the hydrogen generation device shown in FIG. 1A
  • FIG. 1C is a diagram showing an exemplary implementation of the hydrogen generation device shown in FIG. 1A
  • FIG. 1D is a diagram for explaining the lignocellulose of FIG. 1B.
  • Figure 2a shows the concept of a biomass photoelectrochemical system according to an embodiment of the present invention
  • Figure 2b shows the reduction rates of STH and PMA during the day and night in the bias photoelectrochemical system according to an embodiment of the present invention. This is a graph showing.
  • FIGs 3 and 4a to 4g are diagrams showing the results when biomass was incubated at various temperatures of 25, 50, 60, 70 and 90°C in the presence of PMA as an electron transfer mediator.
  • Figure 5 shows the calculated activation energy of PMA reduction by lignocellulosic biomass, lignin, hemicellulose, and cellulose according to an embodiment of the present invention.
  • Figures 6a and 6b are profiles showing the reduction of PMA upon reaction with LC biomass
  • Figure 6a is a UV/Vis absorbance spectrum of a PMA solution pre-incubated with LC biomass oxidation
  • Figure 6b is a UV/Vis absorbance spectrum. This is the amount of PMA reduced by LC biomass and the amount of electrons extracted.
  • Figures 7a and 7b illustrate the extraction of electrons from various biomass using PMA at 60°C.
  • Figure 8 shows FT-IR spectra of various biomass before and after oxidation by PMA at 60°C for 8 hours.
  • Figure 9 is a diagram showing the effect of PMA treatment on the structure of LC biomass, and is a 2D NMR spectrum of LC biomass before (a) and (b) after reaction with PMA at 60°C for 8 hours.
  • Figure 10 is a graph showing the amounts of vanillin and acetovanillone produced during oxidation of lignocellulosic biomass and lignin.
  • Figures 11A to 11D are GC-MS analysis results for identification and quantification of aromatic compounds produced from oxidation of lignin and LC biomass.
  • Figure 12 shows the lignin content of LC biomass obtained from oak before and after reaction with PMA.
  • Figures 13a and 13b show LC analysis results of water-soluble compounds obtained from hemicellulose and cellulose after reaction with PMA.
  • Figure 14 shows the GC analysis results of CO and CO 2 gas generated from LC biomass, lignin, hemicellulose, and cellulose after reaction with PMA.
  • Figures 15a and 15b are SEM images showing the effect of PMA treatment on the microstructure of LC biomass.
  • Figure 16 is a schematic diagram showing electron/proton extraction and value-added chemical production from lignocellulosic biomass through selective depolymerization.
  • Figures 17a and 17b respectively show the effect of oxygen on PMA reduction when reacting with lignin and LC biomass at 60°C for 8 hours.
  • Figures 18 and 19 show linear sweep voltammetry (LSV) and chronoamperometry (CA) curves, respectively.
  • Figure 20 shows 0.8V vs. Chronoamperograms of various anolyte solutions in RHE.
  • Figure 21 shows the detailed structure of a perovskite-based photocathode.
  • Figures 22a to 22f show a perovskite photocathode
  • Figures 23a and 23c show a method of manufacturing a Pt-Ti/FM/perovskite photocathode.
  • Figure 24 shows the results of elemental mapping analysis of Pt-Ti foil, which shows the SEM and EDS elemental mapping analysis results of Ti foil before and after deposition of Pt nanoparticles (20 nm).
  • Figure 25 shows the polarization curve of the perovskite photocathode with and without Pt catalyst for the hydrogen evolution reaction.
  • Figures 26a and 26b show the half-cell performance of the photocathode for solar hydrogen production.
  • Figure 27 shows the half-cell performance of a perovskite photocathode for solar hydrogen production and shows a photoelectrode with Ti foil added.
  • Figure 28 shows the polarization curve of solar light H 2 generated by the Pt-Ti/FM/perovskite photocathode and the theoretical diagram when a bias-free PEC cell is made using electron extraction from PMA reduced by the anode. This shows the estimated maximum photocurrent density.
  • Figure 29 shows the long-term stability in a bias-free photoelectrochemical cell according to an embodiment of the present invention
  • Figure 30 shows the hydrogen production profile in a bias-free, i.e. unassisted PEC system
  • Figure 31 shows This photo shows a two-electrode cell for unassisted solar hydrogen production.
  • Figure 32 shows a control experiment demonstrating the role of reduced PMA as an alternative source of electrons and protons.
  • Figure 33 shows the IPCE spectrum of a bias-free PEC system before and after a 20-hour stability test.
  • Figure 34 is a diagram comparing the STH efficiency of a hydrogen production device using solar energy according to an embodiment of the present invention and a solar-chemical energy conversion device according to the prior art.
  • the present invention relates to a photoelectrochemical (PEC) system using biomass, and to a photoelectrochemical hydrogen generation device using biomass. More specifically, it relates to a hydrogen generation device that produces hydrogen photoelectrochemically using sunlight and easily produces hydrogen by extracting electrons without applying additional voltage, that is, a bias-free hydrogen generation device. . Additionally, the present invention includes a photoelectrode-based electrode for hydrogen production and a photovoltaic cell using the same. Accordingly, the photoelectrochemical hydrogen generation device using biomass according to an embodiment of the present invention may hereinafter be referred to as a photoelectrochemical system, a hydrogen generation system, a hydrogen generation device, a hydrogen production photovoltaic device, etc.
  • the present invention provides a hydrogen generation device that can effectively lower the voltage that must be provided during the oxidation reaction of water by using the decomposition reaction of biomass.
  • the present invention can effectively lower the oxidation reaction voltage when biomass, especially lignocellulose, is used as an electron supplier instead of water, and thus application of additional voltage may be unnecessary.
  • the present invention provides a perovskite photoelectrode, rather than a conventional semiconductor photoelectrode, as an electrode material, enabling high electron transfer efficiency and light absorption in a wide wavelength band from sunlight, thereby enabling bias-free photoelectrochemical It makes hydrogen production possible.
  • the perovskite photoelectrode shows a high reduction current, unlike the semiconductor photoelectrode.
  • the present invention also uses an electron transfer mediator to effectively extract electrons from biomass, and can additionally use a catalyst to effectively extract them. Through this configuration, it is possible to effectively extract electrons from biomass at low temperatures and selectively decompose biomass to obtain useful products.
  • polysaccharides such as cellulose and hemicellulose remaining after selectively decomposing lignin from lignocellulose can be used to produce various chemicals through a biorefinery.
  • the structure of electron extraction from biomass is that of perovskite. Combined with a photoelectrode, it enables efficient voltage-free photoelectrochemical hydrogen production.
  • FIG. 1A is a diagram conceptually showing a hydrogen generation device according to an embodiment of the present invention that implements the above contents
  • FIG. 1B is a cross-sectional view conceptually showing a second electrode in the hydrogen generation device shown in FIG. 1A
  • FIG. 1C is a diagram showing an exemplary implementation of the hydrogen generation device shown in FIG. 1A
  • FIG. 1D is a diagram for explaining the lignocellulose of FIG. 1B.
  • the hydrogen generation device decomposes or oxidizes lignocellulose (LCC) in biomass to obtain decomposition products, and generates hydrogen through the electrons obtained at this time.
  • the first region (R1) and the second region (R2) are separated by a semi-permeable membrane (MM)
  • the first electrode EL1 described herein is a working electrode in which an electron transport medium (EM) is oxidized.
  • the second electrode EL2 described in this specification is a counter electrode capable of generating hydrogen.
  • the first electrode EL1 may be an anode where the electron transfer medium (EM) is reduced.
  • the first electrode EL1 may be a cathode where the electron transport medium (EM) is oxidized.
  • a two-electrode structure consisting of a first electrode (EL1) and a second electrode (EL2), a working electrode and a counter electrode is described, but is not limited thereto. Of course, it can have a three-electrode structure further including a reference electrode.
  • the first electrode EL1 is used to extract electrons from the electron transfer medium (EM) by oxidizing the electron transfer medium (EM), which will be described later.
  • the first electrode EL1 may be made of various conductive materials and may include, for example, a carbon-based material.
  • the carbon-based material includes carbon felt, carbon paper, reduced-graphene oxide (RGO) laminate, porous carbon material, graphene structure, and carbon nanotube. ) It may include one or more types selected from structures, etc.
  • the carbon-based material may further include materials such as carbon paper, glassy carbon, fluorinetaed tin oxide (FTO), and indium tin oxide (ITO).
  • the material of the first electrode EL1 is not limited to this and may be made of various other materials.
  • the first electrode EL1 may be platinum or an electrode containing platinum. If a metal such as platinum is not included, there may be an advantage in reducing manufacturing costs when manufacturing an electrode, and the use of platinum may have electrochemical advantages that are different from other electrodes.
  • the second electrode EL2 is used to produce hydrogen by reducing protons using electrons extracted from an electron transfer medium (EM).
  • EM electron transfer medium
  • the second electrode EL2 may be a photocathode. Accordingly, the second electrode EL2 may include an electrode layer and a photoreactive layer containing a photoreactive material.
  • the second electrode EL2 may be manufactured as a photocathode having a shape similar to that of a solar cell. That is, the second electrode EL2 may include a solar cell unit SLC and an encapsulation unit covering the solar cell unit SLC.
  • the solar cell unit may include a first sub-electrode (SEL1), a light reaction layer (LAL), and a second sub-electrode (SEL2).
  • a hole transport layer (HTL) may be further provided between the first sub-electrode (SEL1) and the photo-reactive layer (LAL), and an electron transport layer (HTL) may be provided between the photo-reactive layer (LAL) and the second sub-electrode (SEL2) ETL) may be further provided.
  • a device is installed between the light-reactive layer (LAL) and the electron transport layer (ETL), a device is installed to stabilize the photo-reactive layer (LAL) and block interfacial recombination between holes in the photo-reactive layer (LAL) and the electron transport layer (ETL).
  • a passivation layer (PSV) may be provided.
  • Encapsulation portions are provided at the edges of the second electrode EL2 and the solar cell unit SLC to optimize redox reactions while protecting the internal structure of the second electrode EL2 from electrolyte.
  • the encapsulation part may include a first metal film (FM) provided on the second sub-electrode (SEL2) and an external electrode film (OEL) provided on the first metal film (FM).
  • the first metal film (FM) and the outer metal film (OEL) may be selected from metals that provide excellent electrical connection and high stability in acidic conditions.
  • the first metal film FM may be a fields metal
  • the external metal film may be Ti or Ti-Pt.
  • a sealant (SLT) may be provided at the edge of each component to protect the outside of the second electrode, and the sealant (SLT) may be made of an acid-stable insulating material, for example, epoxy resin.
  • the second electrode EL2 may include a photoreactive material, for example, a photocatalyst.
  • the photocatalyst may be provided in the form of a coating on the sub-electrode.
  • the photocatalyst may also be provided on a transparent conductive substrate when provided in the electrode layer.
  • transparent means transparent to visible light and/or ultraviolet rays, and may be a substrate made of various conductive metal oxides (for example, ITO; indium tin oxide).
  • ITO indium tin oxide
  • the photocatalyst it may include a photocatalyst that reacts to light in the visible or ultraviolet wavelength range.
  • the visible light may include light in a wavelength band of about 400 nm to about 750 nm, and the ultraviolet ray may include light in a wavelength band of about 10 nm to about 400 nm. If a photocatalyst that reacts to light in the visible or ultraviolet wavelength range is used, an electrochemical reaction using sunlight is possible.
  • the electrode layer for example, the second sub-electrode layer (SEL2)
  • SEL2 is made of a platinum group metal (platinum, ruthenium, rhodium, palladium, osmium, iridium), gold, silver, chromium, iron, and lead.
  • platinum group metal platinum, ruthenium, rhodium, palladium, osmium, iridium
  • gold silver, chromium, iron, and lead.
  • titanium manganese, cobelt, nickel, molybdenum, tungsten, aluminum, silicon, zinc, tin, and alloys thereof.
  • the second electrode EL2 is for generating hydrogen, and each layer of the second electrode EL2 can easily and efficiently absorb sunlight while considering the reduction potential of protons. A material with a small band gap can be selected to allow for this.
  • the photoreactive layer may include perovskite.
  • the perovskite is a light absorber with a small band gap, which can utilize solar flux more effectively and plays a role in lowering the energy requirement required for solar hydrogen production using biomass, especially lignocellulose (LCC), which will be described later. . Through this, high solar-to- H2 (STH) conversion efficiency can be achieved.
  • the first electrode EL1 and the second electrode EL2 may be independently provided in single or plural pieces.
  • the first electrode EL1 and the second electrode EL2 may each be manufactured in various shapes such as wire, sheet, thin film, or mesh.
  • the first electrode (EL1) and the second electrode (EL2) are electrically connected to each other through a wire, etc., and electrons extracted from the first electrode (EL1) are provided to the second electrode (EL2) through the wire, Electrons provided to the second electrode EL2 combine with protons to generate hydrogen.
  • the first electrode EL1 and the second electrode EL2 may be disposed in the same container or in separate containers as shown.
  • the first electrode EL1 and the second electrode EL2 are disposed in the electrolyte.
  • the electrolyte may be divided into a first region (R1) and a second region (R2) with a semi-permeable membrane (MM) in between, and the first region (R1) includes a first electrode (EL1), A second electrode EL2 is provided in each of the two regions R2.
  • An electrolyte is provided in a container provided with the first electrode EL1 and the second electrode EL2.
  • the electrolyte may be an aqueous electrolyte.
  • An electrolyte including an electron transport medium (EM) in a first region (R1) provided with the first electrode (EL1) is provided.
  • the electrolyte may be an acidic electrolyte or a neutral electrolyte.
  • the electrolyte may be an acidic electrolyte with a pH of 2 or less, for example, 2, 1, or 0.
  • the acidic electrolyte is an acid solution of 1 M or more, and the acid solution is one or more acids selected from the group consisting of HCl, H 2 SO 4 , H 2 SO 3 , HNO 3 , HNO 2 and H 3 PO 4 may include.
  • an electron transfer mediator may be suitable for use at or near neutral pH.
  • the electrolyte may have a pH ranging from about 3 to about 7.
  • the semi-permeable membrane (MM) prevents the electron transfer medium (EM) from moving between the first region (R1) where the first electrode (EL1) is provided and the region where the second electrode (EL2) is provided. It prevents the movement of electron transport media (EM) and allows the movement of other ions such as protons.
  • the semi-permeable membrane may be a cation-permeable membrane (MM), for example, a proton-permeable membrane (MM).
  • the semi-permeable membrane (MM) must have a level of impermeability that does not allow the electron transfer medium (EM) to pass through.
  • the semi-permeable membrane (MM) must contain molecules having a molecular weight of 200 or more, 500 or more, or 100 or more. It may be a membrane (MM) that is impermeable to.
  • the semi-permeable membrane (MM) may be a membrane (MM) containing fluoropolymer-copolymer sulfurinated tetrafluoroethylene.
  • the semi-permeable membrane (MM) may be a Nafion membrane (MM), or a functional group-substituted cellulose membrane (MM).
  • An electron transfer medium (EM) is provided in the first region (R1) of the electrolyte, that is, the region where the first electrode (EL1) is provided and the depolymerization portion (DPP).
  • the electron transfer medium goes through oxidation and reduction, decomposes lignocellulose (LCC), generates an addition by-product (VAP), and is oxidized at the first electrode (EL1), thereby transferring electrons to the second electrode (EL2). It serves to provide lignocellulose (LCC) in the depolymerization section (DPP) and is reduced in the process of depolymerizing lignocellulose (LCC) and oxidized in the second electrode (EL2) of the first region (R1).
  • the electron transfer mediator (EM) is provided in the first region (R1) and the depolymerization portion (DPP) as shown, and the first region (R1) and the depolymerization portion (DPP) are
  • the electron transfer mediator (EM) reduced in the depolymerization unit (DPP) is directly or indirectly connected to the first region (R1), and the electron transfer mediator (EM) oxidized in the first region (R1) is provided to the depolymerization unit. It can be circulated in a form that provides it again.
  • an electron transfer medium is capable of receiving or donating electrons, or is capable of receiving or donating electrons and protons. Accordingly, the electron transfer medium (EM) can be expressed in two forms with different charges through reduction and oxidation, with the first electron transfer medium (EM1) in a reduced form and the second electron transfer medium (EM1) in an oxidized form. It can be labeled as an electron transfer medium (EM2).
  • the electron transfer medium (EM) may be an anion, and the charge in the oxidized state of the electron transfer medium (EM) is less than -1, for example, -2, -3, or -4. In one embodiment of the invention, the oxidized state has a charge of -3. In one embodiment of the invention, in one embodiment, the charge in the reduced state of the electron transfer medium (EM) is at least 1 lower than the charge in the oxidized state of the electron transfer medium (EM), for example at least 2 or It is lower than 3. Therefore, when the second electron transfer medium (EM2) has a charge of -3, the first electron transfer medium (EM1) may have a charge of -5.
  • Electron transfer mediators can be colored and can have different colors when oxidized or reduced. In this case, since the color of the electrolyte containing the electron transfer medium (EM) changes, it is possible to check whether the reaction is progressing and whether the electron transfer medium (EM) has changed by changing the color.
  • the electron transfer mediator may be a metal ion or polyoxometalate known to act as an oxidizing agent.
  • the metal ion serving as the oxidizing agent may include metal ions that have multiple stable oxidation numbers and are known to be strong oxidizing agents, for example, Fe or Ce ions.
  • Fe or Ce ions In the case of the metal ions Fe 3+ or Ce 4+ , electrons are extracted during the oxidative decomposition of biomass and can be reduced to Fe 2+ or Ce 3+ , and through this process, they can be used as intermediate mediators.
  • the polyoxometalate may contain at least 2, 3, 6, 7, 12, 18, 24, 30 or 132 metal atoms, and the main metal atom composition and P, Si, S, Ge, W, V, It may include one or more additional heteroatom compositions selected from Mo, Mn, Se, Te, As, Sb, Sn, and Ti.
  • the polyoxometalate has a main metal atom composition and W, V, Mo, Nb, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sn, Pb, Al , and Hg.
  • the metal atom in the polyoxometalate may be selected from the group consisting of W, Mo, V, and Nb, and combinations thereof. In one embodiment of the present invention, the metal atom in the polyoxometalate may be selected from the group consisting of Mo, V, and combinations thereof, and in one embodiment of the present invention, the metal atom in the polyoxometalate is It may be a Mo atom, and in this case, the polyoxometalate may be phosphomolybdic acid (PMA).
  • PMA phosphomolybdic acid
  • the polyoxometallate in addition to W, Mo, V and/or Nb present, further comprises Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and/or Zn. may include. In addition to W, Mo, V, and/or Nb present, the polyoxometallate may additionally include Sn, Pb, Al, and/or Hg.
  • the polyoxometalate has the formula [M 12 O 40 , 4, 5 or 6. In one embodiment, the polyoxometallate has the formula H m M 12 O 40 It's Si.
  • the metal atoms in the polyoxometalate may be the same or different, and in one embodiment of the present invention, the metal atoms are the same.
  • the electron transfer mediator may be phosphomolybdic acid (PMA).
  • the PMA may be [Mo 12 PO 40 ] 3- or [Mo 12 PO 40 ] 5- , and its acidic form, for example, H 3 Mo 12 PO 40 or H 5 Mo 12 PO 40 .
  • [Mo 12 PO 40 ] 3- or [Mo 12 PO 40 ] 5- , and acidic forms thereof, such as H 3 Mo 12 PO 40 or H 5 Mo 12 PO 40 are easily converted to each other through redox reactions. possible.
  • PMA is a biomass material because it exhibits a unique color change from yellow (PMA 3- ) to dark green (PMA 5- ) upon reduction (particularly with absorbance at 700 nm) as well as high solubility and reversible redox behavior at relatively low potentials. Suitable for electron extraction through depolymerization.
  • the electron transfer mediator (EM) may be reduced while decomposing lignocellulose (LCC) and provided to the first region (R1).
  • the oxidized form of the electron transfer mediator (EM) is reduced through the depolymerization reaction of lignocellulose (LCC) and converted into the first electron transfer mediator (EM1), and in this process, vanillin and acetobar, which have high added value, are produced as products.
  • Substances such as aromatic compounds such as nilone, aromatic aliphatic alcohols such as guaiacol, syringol, syringyl aldehyde, methyl syringol, phenylacetone, etc., and organic acids may be produced.
  • products generated through the depolymerization reaction of lignocellulose include, specifically, vanillin, acetovanillone, vanillyl acetone, guaiacol, 4 -Ethylguaiacol, 4-propyl guaiacol, 2,6-dimethoxyphenol, 4-4-hydroxy-3,5 -Dimethoxybenzoaldehyde (hydroxy-3,5-dimethoxybenzaldehyde), 1-(4-hydroxy-3,5-dimethoxyphenyl)ethan-1-one)(1-(4-hydroxy-3,5 -dimethoxyphenyl)ethan-1-one), 4-hydroxy-3,5-dimethoxybenzoic acid, phenol, 1-(4-hydroxy-2 -methylphenyl)ethan-1-one (1-(4-hydroxy-2-methylphenyl)ethan-1-one), 4-hydroxy-3-propylbenzoic acid (4-hydroxy-3-propylbenzoicacid), isobuty
  • Lignocellulose is a biomass composed of cellulose, hemicellulose, and lignin.
  • lignocellulose is one in which a pretreatment process such as a process for separating or removing at least one of lignin, cellulose, or hemicellulose has not been performed, and lignin, cellulose, and hemicellulose are not separated. It is combined in an unsettled state.
  • lignocellulose undergoes hydrolysis pretreatment, and during the hydrolysis pretreatment, cellulose and hemicellulose are decomposed and used as the main carbon source to produce sugars, while lignin is removed by interfering with hydrolysis. It is considered a substance.
  • lignin, cellulose, and hemicellulose are provided in an unseparated state, but the electron transfer mediator (EM) is reduced by selectively decomposing lignin during the depolymerization of lignocellulose (LCC).
  • the selective decomposition of lignin occurs because the aromatic group of lignin has higher energy and is more easily oxidized than the aromatic group of cellulose and hemicellulose, so lignin is preferentially depolymerized in lignocellulose (LCC) biomass, and through this process Transfers electrons and protons to an electron transfer medium (EM).
  • electrons and protons are extracted from raw, untreated lignocellulosic (LCC) biomass (e.g., oak) and its polymer components (i.e., cellulose, hemicellulose, and lignin). do. Because the aromatic groups of lignin have higher energy and are more easily oxidized than the aromatic groups of cellulose and hemicellulose, lignin preferentially depolymerizes in lignocellulosic (LCC) biomass and transfers electrons and protons to electron transfer mediators, such as PMA. to provide.
  • LCC lignocellulosic
  • One embodiment of the present invention includes a method of generating hydrogen using a hydrogen generating device having the above-described structure, wherein the hydrogen is generated by oxidizing the electron transport medium (EM) at the first electrode (EL1). Obtaining an electron transfer medium (EM), reducing the oxidized electron transfer medium (EM), and obtaining hydrogen by reducing a proton with an electron generated from the oxidation at a second electrode (EL2). Includes.
  • the step of reducing the electron transfer medium (EM) is a step of transferring electrons generated in the process of selectively decomposing lignocellulose (LCC) biomass to the electron transfer medium (EM).
  • the electron transfer medium (EM) is reduced during the depolymerization of lignocellulose (LCC) biomass and converted into the reduced electron transfer medium (EM) (i.e., the first electron transfer medium (EM1)).
  • the depolymerization reaction of lignocellulose (LCC) among the main components, the depolymerization reaction of lignin occurs preferentially, and through the decomposition reaction of lignin, aromatic compounds such as vanillin, acetovanillon, guaiacol, syringol, and syringyl aldehyde are produced. , aromatic aliphatic alcohols such as methyl syringol, phenylacetone, etc., and adducts (VAPs) such as organic acids may be generated.
  • VAPs adducts
  • VAP adducts
  • VAP adducts
  • vanillin acetovanillone
  • vanillyl acetone guaiacol
  • 4-ethylguaiacol (4- ethylguaiacol)
  • 4-propyl guaiacol 2,6-dimethoxyphenol (2,6-dimethoxyphenol)
  • 4-hydroxy-3,5-dimethoxybenzoic acid phenol, 1-(4-hydroxy-2-methylphenyl)ethan-1-one (1-(4-hydroxy-2-methylphenyl)ethan-1-one), 4-hydroxy-3-propylbenzoicacid, is
  • the reduced electron transfer medium (EM) is provided in the first region (R1) in the hydrogen generating device, is oxidized at the first electrode (EL1), and provides electrons to the first electrode (EL1).
  • Electrons provided to the first electrode EL1 are provided to the second electrode EL2 through a wire connected between the first electrode EL1 and the second electrode EL2, and reduce protons on the second electrode EL2. generates hydrogen.
  • the second electrode EL2 is a perovskite-based photocathode, and can absorb sunlight and provide the voltage necessary for hydrogen generation.
  • the hydrogen generation device having the above-described structure exhibits very high STH efficiency while using biomass that is not pretreated. To explain this further, it is as follows.
  • the hydrogen generation device uses lignocellulose (LC) biomass as a high-performance organic-inorganic halide perovskite and shows a solar-H 2 (STH) conversion efficiency of up to 24.4%. Present the battery.
  • LC lignocellulose
  • STH solar-H 2
  • aromatic compounds such as vanillin and aceto vanillon, guaiacol, syringol, syringyl aldehyde, methyl syringol, phenyl acetone, etc. are produced through selective depolymerization of lignin in lignocellulosic biomass.
  • Value-added compounds such as aromatic aliphatic alcohols and organic acids can be produced.
  • the electron transfer mediator is at a level equivalent to that of lignin separated through separate pretreatment. It is characterized by depolymerizing lignocellulose and reducing it at the same time. That is, for example, the same inventor's patent publication number 10-2021-0082686 also discloses a hydrogen production system using lignin, but the lignin in the above-mentioned known invention is lignin separately separated from lignocellulose through pretreatment. It does not mean a form with minimal pretreatment, that is, lignocellulose.
  • such lignocellulose is generally used in the form of converting the sugar produced after lignin removal through oxidative depolymerization into biofuel (bioethanol) by fermenting it using enzymes or bacteria. Therefore, it is virtually difficult to use it for hydrogen production without separate pretreatment. This is due to the low lignocellulosic biomass conversion yield and low selectivity due to the low solubility and molecular complexity of lignocellulosic biomass. In addition, due to the complex structure of lignin, it was even more difficult to selectively depolymerize only lignin. For this reason, biorefinement using lignocellulose directly is still lacking in practicality and economic feasibility.
  • the present invention efficiently uses preferential or selective depolymerization of lignin in lignocellulose without separately separating or removing specific components from lignocellulose.
  • the present invention provides a low-temperature/normal-pressure/safe technology that can selectively decompose lignin from lignocellulose while maintaining the original properties of cellulose and hemicellulose.
  • Lignocellulose is a second-generation biomass that does not conflict with food resources.
  • lignocellulosic biomass can be an ideal and practical alternative for hydrogen production.
  • a photocatalyst can be used separately, but the photocatalyst can be used separately without using a conventional inorganic photocatalyst. Hydrogen production using biomass is easily implemented by using a lobskite photocathode.
  • photocatalysts especially inorganic photocatalysts, the low performance of photocatalysts is another major obstacle to practical solar H 2 production.
  • perovskite eg, lead halide perovskite
  • the second electrode cathode
  • perovskite electrodes have tunable bandgaps and energy levels, high absorption coefficients, and excellent charge transport.
  • perovskite-based photoelectrodes for solar hydrogen (H 2 ) production there are no reports related to biomass oxidation due to their vulnerability to water.
  • a photoelectrochemical cell with an STH efficiency of 24.4% is disclosed by combining a perovskite-based photocathode and lignocellulose biomass.
  • additional bias is provided by lowering the potential of the oxidation half-reaction through biomass oxidation ( ⁇ 0.8V vs. RHE) and harvesting the entire visible spectrum with a perovskite-based photocathode. and dramatically higher solar H 2 efficiencies can be achieved without problematic O 2 emissions.
  • PMA is used as a soluble catalyst and electron/proton mediator to easily extract electrons and protons from solid lignocellulosic biomass while producing aromatic compounds such as vanillin and aceto-vanillon, which have high added value, and guai.
  • Aromatic aliphatic alcohols such as alcohol, syringol, syringyl aldehyde, methyl syringol, phenylacetone, etc., and organic acids can be produced.
  • such a solar hydrogen production device and a system including the same can operate stably for 24 hours without any noticeable deterioration in performance.
  • the hydrogen production device according to an embodiment of the present invention is capable of producing hydrogen by solar light in the presence of solar light as well as electrons through an electron transfer mediator obtained during the depolymerization of lignocellulose, thereby enabling bias-free hydrogen production.
  • various operations may be possible depending on the availability of solar power.
  • the hydrogen generation device according to an embodiment of the present invention decomposes the lignocellulose, the electron transfer mediator is reduced, and the reduced electron transfer mediator is oxidized to generate hydrogen, depending on the presence or absence of sunlight.
  • first mode and a second mode that absorbs sunlight to generate hydrogen both the first mode and the second mode can be driven simultaneously.
  • it may vary depending on whether or not there is light including sunlight, but the first mode may correspond to a night when the sunlight is provided to the second electrode, and the second mode may correspond to a night when the sunlight is provided to the second electrode. This may apply during the day provided in .
  • the hydrogen production device uses an electron transfer mediator and undergoes a proton reduction process using sunlight, so that it is an oxygen generation-free reaction in which oxygen generation does not occur at the other electrode. Accordingly, problems that may occur due to oxygen generation are solved.
  • the hydrogen generation device has many advantages over existing solar H 2 production and biomass utilization systems.
  • our biomass photoelectrochemical system enables continuous production of valuable chemicals via biomass depolymerization at night and STH conversion during the day.
  • Figure 2a shows the concept of a biomass photoelectrochemical system according to an embodiment of the present invention
  • Figure 2b shows the reduction rates of STH and PMA during the day and night in the bias photoelectrochemical system according to an embodiment of the present invention. This is a graph showing.
  • PMA exhibits a high reduction rate by depolymerizing and reducing lignocellulosic biomass at night, and is used to efficiently generate H 2 during the day, producing hydrogen with high efficiency both day and night. produced.
  • the depolymerization of biomass was carried out at about 60°C for 12 hours and irradiated with simulated sunlight for 12 hours, corresponding to daylight.
  • the present invention has the advantage of producing hydrogen regardless of day or night.
  • existing photoelectrochemical systems can generate H 2 only during the day.
  • the biomass photoelectrochemical device of the present invention relaxes the stringent requirements of high bandgap photoelectrodes and improves the kinetics of the oxidation half-reaction, resulting in more effective STH conversion.
  • biomass photoelectrochemical systems do not require the use of expensive catalysts (e.g., Ru- and Ir-based catalysts) for the oxidation half-reaction, nor do they generate O 2 , which causes various problems.
  • Aromatic aliphatic alcohols such as bone, syringyl aldehyde, methyl syringol, phenylacetone, etc., and organic acids, etc.
  • Reduced PMA can be easily reoxidized at relatively low potentials and can therefore effectively replace water as a source of electrons and protons for solar H 2 production.
  • the reduced energy requirements for solar H2 production from biomass allow low-bandgap light absorbers, such as perovskites, to more effectively utilize solar flux and achieve record-high STH efficiencies. do.
  • Lignin (alkaline), phosphomolybdic acid (H 3 PMo 12 O 40 , PMA), nitric acid ( ⁇ 65%), sulfuric acid (95.0% +), anhydrous N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), chlorobenzene, toluene, methanol, ethyl acetate, isopropanol, oleylamine, and poly(methyl methacrylate) (PMMA) were purchased from Sigma-Aldrich (USA).
  • lignocellulose (LC) biomass oak trees (> 100 mesh) were obtained from Professor Jaewon Lee's team at Chonnam National University.
  • Multi-walled carbon nanotubes > 95%, OD: 5-15 nm
  • Titanium (Ti) foil thinness 0.25 ⁇ m
  • field metal FM
  • cesium iodide CsI
  • bathocuproin BCP; bathocuproin, 98%) were purchased from Alfa Aesar (USA).
  • PTAA poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]
  • PFNBr poly(9,9-bis(3'-(N,N-dimethyl)-N-ethylammonium- Propyl-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene))dibromide
  • FAI Formidium iodide
  • MABr methylammonium bromide
  • Lead(II) iodide (PbI 2 ) and lead(II) bromide (PbBr 2 ) were purchased from Tokyo Chemical Industry (TCI, Japan).
  • PC 61 BM was purchased from EM Index.
  • PMA was dissolved at 0.25M in 10mL of 0.5MH 2 SO 4 . After sonication for 10 min, 0.375 g of lignin, hemicellulose, cellulose, or lignocellulosic biomass (oak) was added to the PMA solution and then incubated at a constant temperature in an oil bath. Unless otherwise specified, the mixed solution of PMA and biomass was incubated at 60°C for 8 hours. The number of electrons and protons extracted from biomass using PMA was calculated using Equation 1 below.
  • n is the number of electrons participating in the redox reaction (2 when reducing PMA 3- to PMA 5- );
  • C PMA is the molar concentration of PMA;
  • V PMA is the volume of PMA solution;
  • f red is the ratio of reduced PMA;
  • m lignin is the mass of lignin used for electron extraction.
  • the f red value was determined by measuring the absorbance at 700 nm using the Beer-Lambert law.
  • the activation energy for biomass oxidation by PMA ( E a ) was determined using temperature-dependent kinetics according to the Arrhenius equation.
  • k is the proportionality constant in one reaction; R is the gas constant; T is reaction temperature; And A is a pre-exponential factor.
  • the UV/visible absorbance spectrum of the PMA solution was measured using a V-730 UV/vis spectrophotometer (JASCO, Japan). Spectroscopic analysis of lignin, hemicellulose, cellulose and lignocellulosic biomass was performed using a 670/620 Fourier transform infrared (FT-IR) spectrometer (Agilent, USA) and a VNMRS 600 nuclear magnetic resonance (NMR) spectrometer (Agilent, USA). carried out. The photovoltaic properties of the perovskite solar cells were recorded by a Class AAA Oriel Sol3A solar simulator (Newport, USA) using a Keithley 2401 source device under AM 1.5 G (100 mW cm -2 ) illumination.
  • FT-IR Fourier transform infrared
  • NMR nuclear magnetic resonance
  • Spectral discrepancies were corrected using a monosilicon detector covered with a KG-5 filter.
  • the optical properties of the perovskite solar cell were measured using a V-670 UV/vis spectrometer (JASCO, Japan) and a Varian Cary Eclipse Fluorescent spectrometer (Agilent, USA) at an excitation wavelength of 440 nm.
  • the structure of lignocellulosic biomass, cross-sectional images of perovskite films, and platinum nanoparticles on Ti foil were examined using a NOVA Nano scanning electron microscope (SEM) equipped with an energy-dispersive X-ray spectrometer (FEI, USA). The shape was observed.
  • SEM Nano scanning electron microscope
  • UPS spectra of perovskite thin films were obtained using an ESCALAB 250XI UV photoelectron spectrometer (Thermo Fisher Scientific, USA). Pt nanoparticles on Ti foil were analyzed using a JEM 2100 transmission electron microscope (JEOL, Japan).
  • Oxidative depolymerization of lignin and lignocellulosic biomass produced vanillin and acetovanillone.
  • the PMA solution was incubated with lignin or lignocellulosic biomass at 60°C, filtered to remove insoluble aggregates, and mixed with chloroform at a 1:1 volume ratio to extract aromatic compounds. Once phage separation has occurred, add 1 ⁇ L of n-decane to 2 mL of chloroform solution as an internal standard for gas chromatography-mass spectrometry (GC-MS) to identify and quantify aromatic compounds such as vanillin and acetovanillon. did.
  • GC-MS gas chromatography-mass spectrometry
  • GC-MS spectra were measured with a 320-MS mass spectrometer (Bruker, USA) equipped with a 450-GC gas chromatograph and an Rtx-5MS capillary column (30 m ⁇ 0.25 mm ⁇ 0.25 mm; Restek).
  • Split injections (1 ⁇ L) were performed with a GC Pal autosampler (CTC Analytics AG, Switzerland) at a split ratio of 25:1 using He as the carrier gas.
  • the patterned ITO substrate was washed in an ultrasonic bath of acetone and isopropanol for 20 minutes each. The pre-cleaned substrates were dried in an oven and treated with UV/ozone for 30 min. Then, the ITO substrate was transferred to a glove box filled with H 2 O and N 2 containing less than 0.1 ppm of O 2 .
  • PTAA solution (2 mg mL -1 toluene solution) was spin-cast at 6000 rpm for 30 s and then heated at 100 °C for 15 min. After cooling to room temperature, the PFN-Br solution (0.4 mg mL -1 methanol solution) was formed on the PTAA/ITO film.
  • the triple cationic perovskite precursor solution consisted of CsI (0.06 M), FAI (1 M), MABr (0.2 M), PbI 2 (1.1 M), and 1 mL of DMF/DMSO (4/1, v/v) mixed solution. and PbBr 2 (0.2 M) were dissolved and prepared.
  • a trace amount of oleylamine (0.1 wt%) was added to the precursor to increase the crystal orientation of the perovskite layer.
  • a two-step spin coating procedure was adopted to form the perovskite layer, at 1000 rpm for 10 s and at 5000 rpm for 30 s. In the second step, 200 ⁇ L of anti-solvent chlorobenzene was quickly dropped into the center 15 seconds before the end of the rotation process.
  • the obtained light brown film was annealed at 100°C for 30 minutes.
  • PMMA 0.5 mg mL -1 ethyl acetate
  • the electron transport layer was formed by spin-casting PC 61 BM solution (25 mg mL -1 chlorobenzene at 1000 rpm for 30 seconds and BCP in isopropyl alcohol solution (1 mg mL -1 ) at 4000 rpm for 30 seconds.
  • 150 nm thick Ag electrodes were deposited via thermal evaporation at ⁇ 10 -6 Torr.
  • the perovskite photocathode has O 2 ⁇ 0.1 ppm, H 2 O ⁇ 0.1 ppm, and was manufactured based on a perovskite solar cell inside a glove box where N 2 is continuously supplied.
  • a 2.5 cm x 2.5 cm perovskite solar cell was cut into four cells using a diamond cutter knife. Then, the active area of each cell was covered with a 0.3 cm ⁇ 0.3 cm FM rod and heated at 70°C for 2 min.
  • a Pt-Ti foil made of 20 nm Pt nanoparticles deposited on the Ti foil by electron beam evaporation was attached on the solar cell once FM was melted.
  • edges were encapsulated with epoxy (JB Weld, USA), and the copper wire was attached to the second electrode of the perovskite solar cell.
  • the prepared perovskite photocathode was left at room temperature for 12 hours to dry the epoxy sealant.
  • Linear sweep voltammetry (LSV) and chronoamperometry (CA) were performed using a SP-150 Biologic potentiostat (BioLogic Science Instruments, France). Oxidation of pre-reduced PMA was performed using MWCNT paper (0.5 ⁇ 2 cm), Ag/AgCl, and Pt wire as working, reference, and counter electrodes, respectively.
  • CA and gas chromatography (GC) analyzes were performed using an H-Cell with two compartments separated by a Nafion membrane (equivalent to a semipermeable membrane) to prevent reduction of reoxidized PMA at the cathode.
  • the cathode and anode compartments were filled with 0.25M PMA pre-reduced by biomass of 0.5MH 2 SO 4 and 0.5MH 2 SO 4 , respectively.
  • the Nafion membrane separates the anode and cathode half cells.
  • Potentials vs . Ag/AgCl is calculated as potential vs . using Equation 2: Converted to RHE.
  • Photoelectrochemical analysis was performed in a three-electrode configuration using the photocathode, Pt wire, and Ag/AgCl (1 M KCl) as the working, counter, and reference electrodes, respectively.
  • a bias-free photoelectrochemical cell was tested in a homemade two-compartment cell (i.e., a cell with a first region and a second region) under the following conditions: In the cathode compartment corresponding to the second region, a perovskite photocathode was provided as the second electrode and filled with 0.5MH 2 SO 4 , and in the anode compartment corresponding to the first region, a MWCNT paper electrode was provided as the first electrode.
  • FIGs 3 and 4a to 4g are diagrams showing the results when biomass was incubated at various temperatures of 25, 50, 60, 70 and 90°C in the presence of PMA as an electron transfer mediator.
  • Figure 3 is a UV/Vis spectrum of PMA reduction through respective oxidation of lignocellulosic biomass, lignin, hemicellulose, and cellulose at 60°C for 8 hours.
  • Figures 4a to 4g show the results of reduction from PMA 3- to PMA 5- using oxidation of various biomass
  • Figures 4a to 4e show the results at 25°C, 50°C, 60°C, and 70°C in that order, respectively.
  • Figure 4f is the biomass for PMA reduction calculated based on UV/Vis absorbance at 700 nm. The effect of type and incubation temperature is shown
  • Figure 4g is a photograph of PMA solutions incubated with various biomass at various temperatures.
  • a reduction degree higher than 100% means that PMA underwent reduction to two or more electrons and a proton
  • the PMA solution was diluted to 0.05M to show a clear difference.
  • alkaline lignin and lignocellulosic biomass are readily oxidized over this entire temperature range (practically significant above 60°C), providing electrons and protons to PMA.
  • cellulose and hemicellulose could only be oxidized above 90°C.
  • Figure 5 shows the calculated activation energy of PMA reduction by lignocellulosic biomass, lignin, hemicellulose, and cellulose according to an embodiment of the present invention.
  • the activation energy is calculated according to the Arrhenius equation.
  • the activation energy of PMA reduction by oxidation of lignin, cellulose, hemicellulose, and lignocellulose biomass is 24 and 102, respectively. , 79, 47 kJ mol -1 (0.249, 1.057, 0.819, and 0.487 eV).
  • Figures 6A and 6B are profiles showing the reduction of PMA upon reaction with LC biomass
  • Figure 6A is a UV/Vis absorbance spectrum of a PMA solution preincubated with LC biomass oxidation
  • Figure 6B is a UV/Vis absorbance spectrum of a PMA solution preincubated with LC biomass oxidation. This is the amount of PMA reduced by the mass and the amount of electrons extracted.
  • a mixed solution of PMA (0.25 M) and biomass (37.5 mg mL -1 ) was incubated at 60 °C for various reaction times.
  • Figures 7a and 7b show the extraction of electrons from various biomass using PMA at 60°C.
  • Figure 7a shows the PMA reduction rate (%) by oxidation of lignin, hemicellulose, and cellulose at 60°C
  • Figure 7b represents the amount of electrons extracted per unit mass of lignin, hemicellulose, and cellulose oxidation.
  • the present invention analyzed the insoluble and soluble residues of each biomass using various analytical methods before and after reaction with PMA at 60°C for 8 hours. did.
  • Figure 8 shows FT-IR spectra of various biomass before and after oxidation by PMA at 60°C for 8 hours.
  • Figure 9 is a diagram showing the effect of PMA treatment on the structure of LC biomass, and is a 2D NMR spectrum of LC biomass before (a) and (b) after reaction with PMA at 60°C for 8 hours.
  • Figure 10 is a graph showing the amounts of vanillin and acetovanillone produced during oxidation of lignocellulosic biomass and lignin.
  • lignocellulosic biomass After reaction, the soluble residues of each biomass were analyzed by high-performance liquid chromatography (HPLC) for cellulose and hemicellulose, and gas chromatography-mass spectrometry (GCMS) for lignin and lignocellulosic biomass.
  • HPLC high-performance liquid chromatography
  • GCMS gas chromatography-mass spectrometry
  • Figures 11A to 11D are GC-MS analysis results for identification and quantification of aromatic compounds produced from oxidation of lignin and LC biomass. Soluble aromatic compounds from lignin and LC biomass were extracted using chloroform and then analyzed by GC-MS before (a, b) and after (c, d) reaction with PMA at 60°C for 8 h. Vanillin and acetovanillon were detected at 12.7 and 13.8 minutes, respectively. After reacting with PMA for 8 hours, LC biomass and lignin produced 34.1 mg and 43.6 mg of vanillin per gram of biomass, respectively. No vanillin was detected before the reaction. LC biomass produced an additional 44.3 mg of acetovanilone. This additional formation of acetovanillone may be due to differences between the molecular structure of lignin from lignocellulosic biomass and lignin obtained by harsh chemical treatment. It may be due to bond cleavage.
  • Figure 12 shows the lignin content of LC biomass obtained from oak before and after reaction with PMA.
  • the content of lignin was determined by the Klason method. Natural oak contained 23.7% lignin, which decreased to 11.7% after reacting with PMA at 60°C for 8 hours. Through this, it was confirmed that 50.6% of the original lignin was depolymerized in PMA and lignocellulose biomass after oxidation.
  • Figures 13a and 13b are LC analysis results of water-soluble compounds obtained from hemicellulose and cellulose after reaction with PMA
  • Figure 13a is a by-product obtained after reacting hemicellulose with PMA at different temperatures for 8 hours
  • Figure 13b is a by-product obtained after reacting cellulose with PMA for 8 hours. The by-products obtained after reacting with PMA at different temperatures are shown.
  • Hemicellulose and cellulose began to depolymerize substantially above 90°C through cleavage of C-OH, C-O-C, and C-C bonds.
  • Figure 14 shows the GC analysis results of CO and CO 2 gas generated from LC biomass, lignin, hemicellulose, and cellulose after reaction with PMA.
  • Figures 15a and 15b are SEM images showing the effect of PMA treatment on the microstructure of LC biomass
  • Figures 15a and 15b are SEM images of LC biomass before and after reaction with PMA at 60°C for 8 hours, respectively.
  • a hierarchical porous structure was generated in the LC biomass, which can be confirmed that the cellulose component remains almost intact due to the selective depolymerization of lignin in the LC biomass.
  • the image showed that selective removal of lignin through depolymerization resulted in a hierarchical porous microstructure of lignocellulosic biomass after reaction with PMA.
  • Figure 16 is a schematic diagram showing electron/proton extraction and production of value-added chemicals from lignocellulosic biomass through selective depolymerization.
  • lignin can selectively depolymerize to generate electrons and protons with the production of value-added compounds such as vanillin and acetovanillone.
  • the extraction of electrons and protons through preferential oxidation of lignin from lignocellulosic biomass is related to the microstructure of lignocellulosic biomass and biomass oxidation and PMA reduction, two coupled electrochemical half-reactions.
  • Typical lignocellulosic biomass consists of microfibers of highly crystalline cellulose surrounded by amorphous hemicellulose and lignin. Additionally, considering the greater energy density of lignin ( ⁇ 30% greater) compared to cellulose and hemicellulose, one would expect lignin to have greater reactivity than the others. Meanwhile, the way electrons and protons are extracted during biomass oxidation can be understood as two coupled electrochemical half-reactions. Briefly, the thermochemical aerobic oxidation reaction (Equation 3) can be activated by simultaneous oxidation of the substrate (Equation 4) and reduction of dissolved O 2 (ORR; oxygen reduction reaction) Equation 5.
  • Figures 17a and 17b respectively show the effect of oxygen on PMA reduction when reacting with lignin and LC biomass at 60°C for 8 hours, and show the effect of oxygen on PMA reduction when reacting with biomass at 60°C for 8 hours.
  • This spectrum shows the effect of oxygen on oxygen, and continuous O 2 purging increases the amount of PMA reduced by lignin (from 70.1% to 59.1%) and LC biomass (from 64.8% to 45.2%) compared to air purge conditions. led to a significant decrease in
  • PMA reduced by oxidation of lignocellulosic biomass was used as an effective source of electrons and protons instead of water.
  • Figures 18 and 19 show linear sweep voltammetry (LSV) and chronoamperometry (CA) curves, respectively. Each experiment was performed using a carbon nanotube (CNT) paper electrode without a catalyst, and Figure 18 shows the LSV curve of pure 0.5 MH 2 SO 4 , the LSV curve of pristine PMA 3- , and the reduction by lignocellulosic biomass. The LSV curve of PMA 5- and the LSV curve of PMA 5- reduced by lignin are shown, and Figure 19 shows 0.8 V vs. This is the CA curve of PMA 5- reduced by lignocellulosic biomass and lignin in RHE. Here, Figure 19 shows 0.8 V vs.
  • LSV linear sweep voltammetry
  • CA chronoamperometry
  • organic/inorganic lead halide perovskites are used as photoactive materials due to their excellent charge transfer stemming, high absorption from visible to near-infrared spectrum, low energy loss, and defect tolerance characteristics.
  • organicinorganic lead halide perovskite was used.
  • Figure 21 shows the detailed structure of a perovskite-based photocathode. As shown, Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 (PbI 0.83 Br 0.17 ) 3 with a band gap of 1.61 eV was used as the light absorption layer.
  • Figures 22a to 22f show a perovskite photocathode
  • Figures 23a and 23c show a method of manufacturing a Pt-Ti/FM/perovskite photocathode.
  • Figure 22a shows the structure of the perovskite photocathode
  • Figure 22b shows a cross-sectional scanning electron microscope image
  • Figure 22c shows UV/Vis absorbance and photoluminescence spectrum
  • Figure 22d shows a band diagram
  • Figure 22e shows current density-voltage.
  • the curve, Figure 22f is the IPCE spectrum of a perovskite solar cell.
  • Figure 23a shows the step-by-step fabrication process for depositing Ag counter electrodes on perovskite solar cells through thermal evaporation, passivation using FM, cocatalyst treated Pt-Ti foil, and encapsulation with epoxy.
  • Figures 23b and 23c are photographs of the Pt-Ti/FM/perovskite photocathode before and after encapsulation with epoxy resin, respectively.
  • This thin insulating layer can block interfacial recombination between holes in the perovskite and electrons in the ETL and suppress ion migration under continuous illumination.
  • the open circuit potential reached 1.17 V, with an average value of 1.14 ⁇ 0.01 V.
  • Field's metal (FM) and Ti foil (0.25 mm) were used as they provide excellent electrical connection and high stability, respectively, in acidic conditions.
  • the Ti foil was lined with Pt nanoparticles (20 nm) to promote H 2 reduction.
  • the photocathode consists of indium-doped tin oxide (ITO)/PTAA:PFN-Br/Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 (PbI 0.83 Br 0.17 ) 3 perovskite/PMMAPCBM/BCP/Ag/FM/Ti-Pt layers. It has been done.
  • Figure 24 shows the results of elemental mapping analysis of Pt-Ti foil, which shows the SEM and EDS elemental mapping analysis results of Ti foil before and after deposition of Pt nanoparticles (20 nm). Blue and green dots in the EDS mapping image represent Ti and Pt elements, respectively. All scale bars are 2 ⁇ m.
  • Figure 25 shows the polarization curve of the perovskite photocathode with and without Pt catalyst for the hydrogen evolution reaction.
  • the half-cell performance of perovskite-based photocathode for H 2 production was measured at 0.5MH 2 SO 4 (pH 0.65) under simulated solar irradiation.
  • FM modified perovskite FM/perovskite
  • Ti/FM/perovskite Ti foil modified FM/perovskite
  • Pt-Ti/FM/perovskite Pt particle deposited Ti/FM/perovskite optical
  • the onset potentials of solar H 2 generation were 0.49, 0.62, and 1.14 V vs. 0.49, 0.62, and 1.14 V, respectively. It was RHE.
  • Figures 26a and 26b show the half-cell performance of the photocathode for solar hydrogen production, with Figure 26a showing the current density-voltage curve of the FM/perovskite photocathode before and after adding Ti foil, and Figure 26b showing the current density-voltage curve of the photocathode for solar hydrogen production.
  • This shows the stability of FM/perovskite photocathode without Ti foil.
  • the chronoamperogram is 0.44V vs. 0.44V under simulated solar irradiation. Measured at RHE, Figure 26b showed a rapid decline in stability in the absence of Ti foil.
  • Figure 27 shows the half-cell performance of a perovskite photocathode for solar hydrogen production and shows a photoelectrode with Ti foil added. Without Ti foil protection, the FM/perovskite photoelectrode quickly lost its performance in 30 minutes, while the Pt-Ti/FM/perovskite photoelectrode maintained its performance for 8 hours.
  • a biomass-based photoelectrochemical cell for bias-free solar H2 production was fabricated by combining a perovskite-based photocathode and a CNT paper anode.
  • the perovskite-based photocathode was immersed in an acidic medium (0.5 MH 2 SO 4 in water), and the anode was immersed in 0.5 MH 2 SO 4 containing reduced PMA as an electron mediator.
  • Figure 28 shows the polarization curve of solar light H 2 generated by the Pt-Ti/FM/perovskite photocathode and the theoretical diagram when a bias-free PEC cell is made using electron extraction from PMA reduced by the anode. This shows the estimated maximum photocurrent density.
  • the maximum theoretical photocurrent density of 20.4 mA cm -2 (at 0.44V vs. RHE) is obtained at the photocathode under light conditions (for the H 2 production) and under dark conditions (for PMA reoxidation). It was expected from the intersection of the two LSV curves of the anode. Under simulated AM 1.5G single solar illumination, a maximum current density (J) of 19.8 mA cm -2 was obtained with an efficiency of almost 1 Faraday without external bias.
  • Figure 29 shows the long-term stability in a bias-free photoelectrochemical cell according to an embodiment of the present invention
  • Figure 30 shows the hydrogen production profile in a bias-free, i.e. unassisted PEC system
  • Figure 31 shows This photo shows a two-electrode cell for unassisted solar hydrogen production.
  • Figure 32 shows a control experiment showing the role of reduced PMA as an alternative source of electrons and protons. Unlike the above, no photocurrent was observed when unreacted PMA 3- was used. This confirms the function of reduced PMA (PMA 5- ) as an alternative resource for electrons and protons.
  • PMA 5- reduced PMA
  • Figure 33 shows the IPCE spectrum of a bias-free PEC system before and after a 20-hour stability test
  • Figure 34 and Table 1 show the solar-powered hydrogen production device according to an embodiment of the present invention and the prior art. This is a picture comparing the STH efficiency of solar-chemical energy conversion devices.
  • the IPCE spectrum showed that the photoelectrochemical cell enables panchromatic solar H 2 production. Moreover, as shown in Figure 29, the photoelectrochemical device was very stable under single solar illumination for more than 20 hours without performance degradation. Above all, the 24.4% STH efficiency represents the highest data reported to date among solar H 2 production systems using a single photoelectrode, regardless of device type for water splitting, such as photoelectrochemical and photovoltaic-assisted photoelectrochemical/electrochemical devices. did.

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Abstract

This hydrogen generator includes a first region and a second region separated by a semi-permeable membrane, a first electrode provided in the first region, a second electrode electrically connected to the first electrode and provided in the second region, a depolymerization unit separated from the second region, and an electron transfer medium provided in the first region and the depolymerization unit. The electron transfer medium is simultaneously reduced while decomposing lignocellulose in the depolymerization unit, and oxidized at the first electrode in the first region, and protons are reduced at the second electrode by electrons generated from the oxidation.

Description

수소 생성 장치hydrogen generation device
본 발명은 수소 생성 장치에 관한 것으로, 상세하게는 리그노셀룰로오스의 해중합 반응을 이용한 바이어스 프리 수소 생성 장치에 관한 것이다.The present invention relates to a hydrogen generation device, and more specifically to a bias-free hydrogen generation device using the depolymerization reaction of lignocellulose.
최근 화석 연료가 아닌 태양광을 이용하여 수소 생산하기 위한 연구가 이루어지고 있다. 특히 태양광을 이용하여 물로부터 전자를 추출한 후, 물로부터 추출된 전자를 수소 생산(hydrogen evolution), 이산화탄소 저감(CO2 reduction), 질소환원(nitrogen reduction), 산소환원반응(oxygen reduction) 및 환원적 효소 반응(reductive enzyme reactions)에 이용함으로써 화석 연료를 대체할 수 있는 연료 및 부가 가치 높은 화합물을 생산하는 연구가 이루어지고 있다. 이러한 전자를 이용한 광전기화학 반응에서, 산화물 반도체 물질은 상대적으로 높은 안정성으로 인해 물 분해 광전극 촉매로 활용되고 있으나, 낮은 흡광 효율, 낮은 촉매 활성, 약한 전기 전도도 등으로 인해, 높은 전압 및 고가의 촉매가 필요한 문제점이 있으며, 이를 개선하기 위한 개발이 요구되고 있다.Recently, research has been conducted to produce hydrogen using solar energy rather than fossil fuels. In particular, after extracting electrons from water using sunlight, the electrons extracted from water are used for hydrogen evolution, carbon dioxide reduction, nitrogen reduction, oxygen reduction, and reduction. Research is being conducted to produce fuels that can replace fossil fuels and compounds with high added value by using them in reductive enzyme reactions. In photoelectrochemical reactions using electrons, oxide semiconductor materials are used as water-splitting photoelectrode catalysts due to their relatively high stability, but due to low light absorption efficiency, low catalytic activity, and weak electrical conductivity, high voltage and expensive catalysts are used. There are problems that require development, and development to improve them is required.
본 발명은 고효율의 태양열-수소생산 효율을 갖는 수소 생성 장치를 제공하는 것을 목적으로 한다.The purpose of the present invention is to provide a hydrogen generation device with high solar heat-hydrogen production efficiency.
본 발명의 일 실시예에 따른 수소 생성 장치는, 반투과성 멤브레인에 의해 구분된 제1 영역과 제2 영역, 상기 제1 영역에 제공된 제1 전극, 상기 제1 전극에 전기적으로 연결되며 상기 제2 영역에 제공된 제2 전극, 상기 제2 영역과 분리된 해중합부, 상기 제1 영역과 상기 해중합부에 제공된 전자전달 매개체를 포함한다. 상기 전자전달 매개체는 상기 해중합부에서 리그노셀룰로오스를 분해함과 동시에 환원되고 상기 제1 영역의 상기 제1 전극에서 산화되며, 상기 제2 전극에 서 상기 산화로부터 발생된 전자로 양성자가 환원된다.A hydrogen generation device according to an embodiment of the present invention includes a first region and a second region separated by a semi-permeable membrane, a first electrode provided in the first region, and electrically connected to the first electrode and the second region. It includes a second electrode provided in, a depolymerization portion separated from the second region, and an electron transfer mediator provided in the first region and the depolymerization portion. The electron transfer mediator decomposes lignocellulose in the depolymerization section and is simultaneously reduced and oxidized at the first electrode in the first region, and protons are reduced with electrons generated from the oxidation at the second electrode.
본 발명의 일 실시예에 있어서, 상기 리그노셀룰로오스는 셀룰로오스, 헤미셀룰로오스, 및 리그닌이 분리되지 않은 상태로 결합된 것이다.In one embodiment of the present invention, the lignocellulose is a combination of cellulose, hemicellulose, and lignin in a non-separated state.
본 발명의 일 실시예에 있어서, 상기 전자전달 매개체와 상기 셀룰로오스, 상기 헤미셀룰로오스, 및 상기 리그닌의 반응 시 상기 리그닌이 선택적으로 분해될 수 있다.In one embodiment of the present invention, when the electron transfer mediator reacts with the cellulose, hemicellulose, and lignin, the lignin may be selectively decomposed.
본 발명의 일 실시예에 있어서, 상기 리그노셀룰로오스와 상기 전자전달 매개체의 반응 후 부산물로 바닐린, 아세토 바닐론, 구아이아콜, 시린골, 시린질 알데하이드, 메틸 시린골, 페닐 아세톤, 및 유기산 중 적어도 하나가 생성될 수 있다.In one embodiment of the present invention, after the reaction of the lignocellulose with the electron transfer mediator, by-products include vanillin, aceto vanillon, guaiacol, syringol, syringyl aldehyde, methyl syringol, phenyl acetone, and organic acids. At least one can be created.
본 발명의 일 실시예에 있어서, 상기 제2 전극은 페로브스카이트계 광음극일 수 있다.In one embodiment of the present invention, the second electrode may be a perovskite-based photocathode.
본 발명의 일 실시예에 있어서, 상기 제2 전극은 태양 전지부를 포함하며, 상기 태양 전지부는: 제1 서브전극, 상기 제1 서브전극 상에 제공된 광반응층, 상기 광반응층 상에 제공된 제2 서브전극을 포함하며, 상기 광반응층은 페로브스카이트를 포함할 수 있다.In one embodiment of the present invention, the second electrode includes a solar cell unit, wherein the solar cell unit includes: a first sub-electrode, a photoreactive layer provided on the first sub-electrode, and a photoreactive layer provided on the photoreactive layer. It includes 2 sub-electrodes, and the photoreactive layer may include perovskite.
본 발명의 일 실시예에 있어서, 상기 제2 전극은, 상기 제1 서브전극과 상기 광흡수층 사이에 제공된 정공 수송층, 및 상기 광흡수층과 제2 서브전극 사이에 제공된 전자 수송층 중 적어도 하나를 더 포함할 수 있다.In one embodiment of the present invention, the second electrode further includes at least one of a hole transport layer provided between the first sub-electrode and the light absorption layer, and an electron transport layer provided between the light absorption layer and the second sub-electrode. can do.
본 발명의 일 실시예에 있어서, 상기 광흡수층과 상기 전자 수송층 사이에 제공된 패시베이션층을 더 포함할 수 있다.In one embodiment of the present invention, a passivation layer provided between the light absorption layer and the electron transport layer may be further included.
본 발명의 일 실시예에 있어서, 상기 태양 전지부의 외측에 제공되어 상기 태양 전지부를 보호하는 봉지부를 더 포함하며, 상기 봉지부는: 상기 제2 서브 전극 상에 제공된 제1 금속막, 및 상기 제1 금속막 상에 제공된 외부 금속막을 포함할 수 있다.In one embodiment of the present invention, it further includes an encapsulation provided outside the solar cell unit to protect the solar cell unit, wherein the encapsulation unit includes: a first metal film provided on the second sub-electrode, and the first metal film provided on the second sub-electrode. 1 May include an external metal film provided on the metal film.
본 발명의 일 실시예에 있어서, 상기 제1 금속막은 필즈 금속을 포함하며, 상기 외부 금속막은 Ti 또는 Ti-Pt를 포함할 수 있다.In one embodiment of the present invention, the first metal layer may include fields metal, and the external metal layer may include Ti or Ti-Pt.
본 발명의 일 실시예에 있어서, 상기 제2 전극의 적어도 일부의 외면을 감싸는 실런트를 포함할 수 있다.In one embodiment of the present invention, a sealant may be included surrounding at least a portion of the outer surface of the second electrode.
본 발명의 일 실시예에 있어서, 상기 수소 생성 장치는 태양광의 유무의 따라, 상기 리그노셀룰로오스를 분해하여 상기 전자전달 매개체가 환원되고, 상기 환원된 전자전달 매개체가 산화되며 수소를 생성하는 제1 모드와, 상기 태양광을 흡수하여 수소를 생성하는 제2 모드 중 적어도 하나로 구동될 수 있다. 상기 제1 모드는 상기 태양광이 상기 제2 전극에 제공되는 밤에 해당하고, 상기 제2 모드는 상기 태양광이 상기 제2 전극에 제공되는 낮에 해당할 수 있다.In one embodiment of the present invention, the hydrogen generation device decomposes the lignocellulose, depending on the presence or absence of sunlight, the electron transfer mediator is reduced, and the reduced electron transfer mediator is oxidized to generate hydrogen. It may be driven in at least one of a mode and a second mode in which hydrogen is generated by absorbing the sunlight. The first mode may correspond to a night when sunlight is provided to the second electrode, and the second mode may correspond to a day when the sunlight is provided to the second electrode.
본 발명의 일 실시예에 있어서, 상기 수소 생성 장치는 바이어스 프리일 수 있다.In one embodiment of the present invention, the hydrogen generation device may be bias-free.
본 발명의 일 실시예에 있어서, 상기 수소 생성 장치는 산소 발생 프리일 수 있다.In one embodiment of the present invention, the hydrogen generation device may be free of oxygen generation.
본 발명의 일 실시예에 있어서, 상기 전자전달 매개체는 폴리옥소메탈레이트일 수 있다. 본 발명의 일 실시예에 있어서, 상기 전자전달 매개체는 포스포몰리브드산일 수 있다.In one embodiment of the present invention, the electron transfer mediator may be polyoxometalate. In one embodiment of the present invention, the electron transfer mediator may be phosphomolybdic acid.
본 발명은 상기 수소 생성 장치를 이용한 수소 생산 방법을 포함하며, 수소 생산 방법은, 제1 전극에서 전자전달 매개체(mediator)를 산화시켜 산화된 전자전달 매개체를 수득하는 단계, 상기 산화된 전자전달 매개체를 환원시키는 단계, 및 제2 전극에서 상기 산화로부터 발생된 전자로 양성자를 환원시켜 수소를 수득하는 단계를 포함한다. 상기 전자전달 매개체를 환원시키는 단계는 리그노셀룰로오스 바이오매스를 선택적으로 분해하는 과정에서 발생된 전자를 상기 전자전달 매개체로 전달하는 단계이다.The present invention includes a method of producing hydrogen using the hydrogen generating device, the method of producing hydrogen comprising the steps of oxidizing an electron transfer mediator at a first electrode to obtain an oxidized electron transfer mediator, the oxidized electron transfer mediator reducing a proton with an electron generated from the oxidation at a second electrode to obtain hydrogen. The step of reducing the electron transfer mediator is a step of transferring electrons generated in the process of selectively decomposing lignocellulosic biomass to the electron transfer mediator.
본 발명의 일 실시예에 따르면 전자 전달 매개체를 통해서 저온에서 바이오매스를 선택적으로 분해할 수 있다.According to one embodiment of the present invention, biomass can be selectively decomposed at low temperature through an electron transfer mediator.
본 발명의 일 실시예에 따르면 리그노셀룰로오스로부터 다당류의 특성은 유지한채 리그닌만을 선택적으로 분해하여 방향족/지방족 고부가 화합물을 생성할 수 있으며, 잔류 다당류는 기존 바이오리파이너리에 활용할 수 있다.According to one embodiment of the present invention, aromatic/aliphatic high value-added compounds can be produced by selectively decomposing lignin from lignocellulose while maintaining the properties of polysaccharides, and the residual polysaccharides can be utilized in existing biorefineries.
본 발명의 일 실시예에 따르면, 바이오매스로부터 효과적으로 전자를 추출할 수 있어 효율적인 수소 생산이 가능하다.According to one embodiment of the present invention, electrons can be effectively extracted from biomass, making efficient hydrogen production possible.
또한, 본 발명의 일 실시예에 따르면 페로브스카이트 광전극과 결합하였을 때, 바이어스 프리 수소 생성 장치의 구현이 가능하다.Additionally, according to one embodiment of the present invention, when combined with a perovskite photoelectrode, it is possible to implement a bias-free hydrogen generation device.
도 1a은 상기한 내용을 구현하는 본 발명의 일 실시예에 따른 수소 생성 장치를 개념적으로 나타낸 도면이고, 도 1b는 도 1a에 도시된 수소 생성 장치에 있어서 제1 전극을 개념적으로 도시한 단면도이며, 도 1c는 도 1a에 도시된 수소 생성 장치를 예시적으로 구현한 것을 나타낸 도면이며, 도 1d는 도 1b의 리그노셀룰로오스를 설명하기 위한 도면이다.FIG. 1A is a diagram conceptually showing a hydrogen generation device according to an embodiment of the present invention that implements the above contents, and FIG. 1B is a cross-sectional view conceptually showing the first electrode in the hydrogen generation device shown in FIG. 1A. , FIG. 1C is a diagram showing an exemplary implementation of the hydrogen generation device shown in FIG. 1A, and FIG. 1D is a diagram for explaining the lignocellulose of FIG. 1B.
도 2a는 본 발명의 일 실시예에 따른 바이오매스 광전기화학 시스템의 개념을 도시한 것이며, 도 2b는 본 발명의 일 실시예에 따른 바이어스 광전기화학시스템에 있어서, 낮과 밤의 STH와 PMA의 환원율을 도시한 그래프이다.Figure 2a shows the concept of a biomass photoelectrochemical system according to an embodiment of the present invention, and Figure 2b shows the reduction rates of STH and PMA during the day and night in the bias photoelectrochemical system according to an embodiment of the present invention. This is a graph showing.
도 3 및 도 4a 내지 도 4g는 전자전달 매개체로서 PMA가 존재할 때 25, 50, 60, 70 및 90℃의 다양한 온도에서 바이오매스가 인큐베이션되었을 때의 결과를 나타낸 도면들이다.Figures 3 and 4a to 4g are diagrams showing the results when biomass was incubated at various temperatures of 25, 50, 60, 70 and 90°C in the presence of PMA as an electron transfer mediator.
도 5는 본 발명의 일 실시예에 따른 리그노셀룰로오스 바이오매스, 리그닌, 헤미셀룰로오스 및 셀룰로오스에 의한 PMA 환원의 계산된 활성화 에너지를 나타낸 것이다.Figure 5 shows the calculated activation energy of PMA reduction by lignocellulosic biomass, lignin, hemicellulose, and cellulose according to an embodiment of the present invention.
도 6a 및 도 6b는 LC 바이오매스와 반응 시 PMA의 환원를 보여주는 프로파일로서, 도 6a는 LC 바이오매스 산화와 함께 사전 인큐베이트된(pre-incubated) PMA 용액의 UV/Vis 흡광도 스펙트럼이며, 도 6b는 LC 바이오매스에 의해 환원된 PMA양 및 전자 추출량이다.Figures 6a and 6b are profiles showing the reduction of PMA upon reaction with LC biomass, Figure 6a is a UV/Vis absorbance spectrum of a PMA solution pre-incubated with LC biomass oxidation, and Figure 6b is a UV/Vis absorbance spectrum. This is the amount of PMA reduced by LC biomass and the amount of electrons extracted.
도 7a 및 도 7b는 60℃에서 PMA를 사용하여 다양한 바이오매스에서 전자의 추출을 도시한 것이다.Figures 7a and 7b illustrate the extraction of electrons from various biomass using PMA at 60°C.
도 8은 60℃에서 8시간 동안 PMA에 의한 산화 전후의 다양한 바이오매스의 FT-IR 스펙트럼을 나타낸 것이다.Figure 8 shows FT-IR spectra of various biomass before and after oxidation by PMA at 60°C for 8 hours.
도 9는 LC 바이오매스 구조에 대한 PMA 처리의 효과를 나타낸 도면으로서, 60℃에서 8시간 동안 PMA와 반응하기 (a)전과 (b)후의 LC 바이오매스의 2D NMR 스펙트럼이다.Figure 9 is a diagram showing the effect of PMA treatment on the structure of LC biomass, and is a 2D NMR spectrum of LC biomass before (a) and (b) after reaction with PMA at 60°C for 8 hours.
도 10은 리그노셀룰로오스 바이오매스 및 리그닌 산화시에 생성된 바닐린 및 아세토바닐론의 양을 도시한 그래프이다.Figure 10 is a graph showing the amounts of vanillin and acetovanillone produced during oxidation of lignocellulosic biomass and lignin.
도 11a 내지 도 11d는 리그닌 및 LC 바이오매스의 산화로부터 생성된 방향족 화합물의 식별 및 정량화를 위한 GC-MS 분석 결과이다.Figures 11A to 11D are GC-MS analysis results for identification and quantification of aromatic compounds produced from oxidation of lignin and LC biomass.
도 12는 PMA와의 반응 전후에 참나무에서 얻은 LC 바이오매스의 리그닌 함량을 나타낸 것이다.Figure 12 shows the lignin content of LC biomass obtained from oak before and after reaction with PMA.
도 13a 및 도 13b는 PMA와의 반응 후 헤미셀룰로오스와 셀룰로오스로부터 얻은 수용성 화합물의 LC 분석 결과이다.Figures 13a and 13b show LC analysis results of water-soluble compounds obtained from hemicellulose and cellulose after reaction with PMA.
도 14는 PMA와의 반응 후 LC 바이오매스, 리그닌, 헤미셀룰로오스 및 셀룰로오스에서 생성된 CO 및 CO2 기체의 GC 분석 결과 이다.Figure 14 shows the GC analysis results of CO and CO 2 gas generated from LC biomass, lignin, hemicellulose, and cellulose after reaction with PMA.
도 15a 및 15b는 LC 바이오매스의 미세구조에 대한 PMA 처리의 효과를 나타낸 SEM 이미지이다.Figures 15a and 15b are SEM images showing the effect of PMA treatment on the microstructure of LC biomass.
도 16은 선택적 해중합을 통한 리그노셀룰로오스 바이오매스로부터의 전자/양성자 추출 및 부가 가치 화학 물질 생산을 나타낸 개략도이다.Figure 16 is a schematic diagram showing electron/proton extraction and value-added chemical production from lignocellulosic biomass through selective depolymerization.
도 17a 및 도17b는 각각 60℃에서 8시간 동안 리그닌과 LC 바이오매스와 반응할 때 PMA 환원에 대한 산소의 영향을 나타낸 것이다.Figures 17a and 17b respectively show the effect of oxygen on PMA reduction when reacting with lignin and LC biomass at 60°C for 8 hours.
도 18 및 도 19는 각각 선형주사전위법(Linear sweep voltammetry, LSV) 및 시간대전류법(chronoamperometry, CA) 커브를 나타낸 것이다.Figures 18 and 19 show linear sweep voltammetry (LSV) and chronoamperometry (CA) curves, respectively.
도 20은 0.8V vs. RHE에서 다양한 양극액 용액의 크로노암페로그램이다.Figure 20 shows 0.8V vs. Chronoamperograms of various anolyte solutions in RHE.
도 21는 페로브스카이트 기반 광음극의 세부 구조를 도시한 것이다.Figure 21 shows the detailed structure of a perovskite-based photocathode.
도 22a 내지 도 22f는 페로브스카이트 광음극를 나타낸 것이며, 도 23a 및 도23c는 Pt-Ti/FM/페로브스카이트 광음극 제조 방법을 나타낸 도면이다.Figures 22a to 22f show a perovskite photocathode, and Figures 23a and 23c show a method of manufacturing a Pt-Ti/FM/perovskite photocathode.
도 24는 Pt-Ti 호일의 원소 매핑 분석 결과로서, Pt 나노입자(20 nm) 증착 전후의 Ti 호일의 SEM 및 EDS 원소 매핑 분석 결과이다.Figure 24 shows the results of elemental mapping analysis of Pt-Ti foil, which shows the SEM and EDS elemental mapping analysis results of Ti foil before and after deposition of Pt nanoparticles (20 nm).
도 25는 수소 발생 반응을 위해 Pt 촉매가 있거나 없는 조건에서의 페로브스카이트 광음극의 편광 곡선을 도시한 것이다.Figure 25 shows the polarization curve of the perovskite photocathode with and without Pt catalyst for the hydrogen evolution reaction.
도 26a 및 26b는 태양광 수소 생산을 위한 광음극의 반쪽 전지 성능을 나타낸 것이다.Figures 26a and 26b show the half-cell performance of the photocathode for solar hydrogen production.
도 27은 태양광 수소 생산을 위한 페로브스카이트 광음극의 반쪽 전지 성능을 나타낸 것으로서 Ti 호일이 부가된 광전극을 나타낸 것이다.Figure 27 shows the half-cell performance of a perovskite photocathode for solar hydrogen production and shows a photoelectrode with Ti foil added.
도 28은 Pt-Ti/FM/페로브스카이트 광음극에 의해 생성된 태양광 H2의 분극 곡선과 양극에 의해 환원된 PMA로부터 전자 추출을 이용하여, 바이어스 프리 PEC 전지를 만들었을 때의 이론적인 최대 광전류 밀도 예상치를 나타낸 것이다.Figure 28 shows the polarization curve of solar light H 2 generated by the Pt-Ti/FM/perovskite photocathode and the theoretical diagram when a bias-free PEC cell is made using electron extraction from PMA reduced by the anode. This shows the estimated maximum photocurrent density.
도 29는 본 발명의 일 실시예에 따른 바이어스 프리 광전기화학 전지에서의 장기 안정성을 도시한 것이며, 도 30은 바이어스 프리, 즉, 비보조 PEC 시스템에서의 수소 생산 프로파일을 아나낸 것이며, 도 31은 비보조 태양광 수소 생산을 위한 2전극 전지를 도시한 사진이다.Figure 29 shows the long-term stability in a bias-free photoelectrochemical cell according to an embodiment of the present invention, Figure 30 shows the hydrogen production profile in a bias-free, i.e. unassisted PEC system, and Figure 31 shows This photo shows a two-electrode cell for unassisted solar hydrogen production.
도 32는 전자와 양성자의 대체 공급원로서 환원된 PMA의 역할을 보여주는 대조 실험을 나타낸 것이다.Figure 32 shows a control experiment demonstrating the role of reduced PMA as an alternative source of electrons and protons.
도 33은 20시간 안정성 테스트 전후의 바이어스 없는(bias-free) PEC 시스템의 IPCE 스펙트럼을 도시한 것이다.Figure 33 shows the IPCE spectrum of a bias-free PEC system before and after a 20-hour stability test.
도 34는 본 발명의 일 실시예에 따른 태양광 이용 수소 생산 장치와 종래 기술에 따른 태양광-화학 에너지 변환 장치의 STH 효율 비교한 그림이다.Figure 34 is a diagram comparing the STH efficiency of a hydrogen production device using solar energy according to an embodiment of the present invention and a solar-chemical energy conversion device according to the prior art.
하기의 용어가 당업자에 의해 잘 이해될 것으로 여겨지지만, 하기의 정의는 현재 개시된 발명 요지의 설명을 용이하게 하기 위해 기재된다.Although the following terms are believed to be well understood by those skilled in the art, the following definitions are set forth to facilitate description of the presently disclosed subject matter.
달리 정의되지 않는 한, 본 명세서에 사용되는 모든 기술적 및 과학적 용어는 현재 개시된 발명 요지가 속하는 기술 분야의 당업자가 통상적으로 이해하는 바와 동일한 의미를 갖는다. 본 명세서에 기술된 것과 유사하거나 동등한 임의의 방법, 장치, 및 재료가 현재 개시된 발명 요지의 실시 또는 검사에 사용될 수 있지만, 이제 대표적인 방법, 장치, 및 재료가 기술된다.Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by a person skilled in the art to which the presently disclosed subject matter pertains. Although any methods, devices, and materials similar or equivalent to those described herein can be used in the practice or testing of the presently disclosed subject matter, representative methods, devices, and materials are now described.
본 발명은 다양한 변경을 가할 수 있고 여러 가지 형태를 가질 수 있는 바, 특정 실시예들을 도면에 예시하고 본문에 상세하게 설명하고자 한다. 그러나, 이는 본 발명을 특정한 개시 형태에 대해 한정하려는 것이 아니며, 본 발명의 사상 및 기술 범위에 포함되는 모든 변경, 균등물 내지 대체물을 포함하는 것으로 이해되어야 한다.Since the present invention can be subject to various changes and have various forms, specific embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, and should be understood to include all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention.
이하, 첨부한 도면들을 참조하여 본 발명의 바람직한 실시예를 보다 상세하게 설명하고자 한다.Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the attached drawings.
본 발명은 바이오매스를 이용한 광전기화학 시스템(photoelectrochemical (PEC) system)에 관한 것으로서, 바이오매스를 이용한 광전기화학 수소 생성 장치에 관한 것이다. 좀더 구체적으로는 태양광을 이용하여 광전기화학적으로 수소를 생산하되 부가적인 전압의 인가없이 전자를 추출함으로써 용이하게 수소를 생산하는 수소 생성 장치, 즉, 바이어스 프리(bias free) 수소 생성 장치에 관한 것이다. 또한, 본 발명은 이러한 수소 생산을 위한 광전극 기반의 전극 및 이를 이용한 광전지 셀을 포함한다. 이에, 본 발명의 일 실시예에 따른 바이오매스 이용 광전기화학적 수소 생성 장치는 광전기화학 시스템, 수소 생성 시스템, 수소 생성 장치, 수소 생산 광전지 장치 등으로 이하에서 지칭될 수 있다.The present invention relates to a photoelectrochemical (PEC) system using biomass, and to a photoelectrochemical hydrogen generation device using biomass. More specifically, it relates to a hydrogen generation device that produces hydrogen photoelectrochemically using sunlight and easily produces hydrogen by extracting electrons without applying additional voltage, that is, a bias-free hydrogen generation device. . Additionally, the present invention includes a photoelectrode-based electrode for hydrogen production and a photovoltaic cell using the same. Accordingly, the photoelectrochemical hydrogen generation device using biomass according to an embodiment of the present invention may hereinafter be referred to as a photoelectrochemical system, a hydrogen generation system, a hydrogen generation device, a hydrogen production photovoltaic device, etc.
본 발명은 물의 산화 반응 시의 제공해야 하는 전압을 바이오매스의 분해 반응을 이용하여 효과적으로 낮출 수 있는 수소 생성 장치를 제공한다. 여기서, 본 발명은 바이오매스, 특히 리그노셀룰로오스를 물 대신 전자 공급체로 사용하였을 때, 산화 반응 전압을 효과적으로 낮출 수 있으며 이에 따른 추가적인 전압의 인가가 불필요할 수 있다.The present invention provides a hydrogen generation device that can effectively lower the voltage that must be provided during the oxidation reaction of water by using the decomposition reaction of biomass. Here, the present invention can effectively lower the oxidation reaction voltage when biomass, especially lignocellulose, is used as an electron supplier instead of water, and thus application of additional voltage may be unnecessary.
또한, 본 발명은 전극 재료로서 기존의 반도체 광전극이 아닌, 페로브스카이트 광전극을 제공함으로써 높은 전자 전달 효율 및 태양광에서의 넓은 파장 대역의 광 흡수가 가능하며, 이를 통해 바이어스 프리 광전기 화학적 수소 생산을 구현할 수 있게 한다. 여기서, 상기 페로브스카이트 광전극은 반도체 광전극과 달리 높은 환원 전류를 보인다.In addition, the present invention provides a perovskite photoelectrode, rather than a conventional semiconductor photoelectrode, as an electrode material, enabling high electron transfer efficiency and light absorption in a wide wavelength band from sunlight, thereby enabling bias-free photoelectrochemical It makes hydrogen production possible. Here, the perovskite photoelectrode shows a high reduction current, unlike the semiconductor photoelectrode.
본 발명은 또한, 바이오매스로부터 효과적으로 전자를 추출하기 위한 전자전달 매개체를 사용하며, 이에 더해 이를 효과적으로 추출하기 위한 촉매를 부가적으로 사용할 수 있다. 이러한 구성을 통해 저온에서 효과적으로 바이오매스로부터 전자를 추출하고 선택적으로 바이오매스를 분해하여 유용한 생성물을 얻을 수 있다. 특히 본 발명은 리그노셀룰로오스로부터 리그닌을 선택적으로 분해 후 남은 셀룰로오스와 헤미셀룰로오스와 같은 다당류는 바이오 리파이너리를 통해 다양한 화학물질을 생산하는데 활용할 수 있다.이러한 바이오매스로부터의 전자 추출 구조는 페로브스카이트의 광전극과 결합하여 무전압 광전기화학적 수소 생산이 효율적으로 가능하게 한다.The present invention also uses an electron transfer mediator to effectively extract electrons from biomass, and can additionally use a catalyst to effectively extract them. Through this configuration, it is possible to effectively extract electrons from biomass at low temperatures and selectively decompose biomass to obtain useful products. In particular, in the present invention, polysaccharides such as cellulose and hemicellulose remaining after selectively decomposing lignin from lignocellulose can be used to produce various chemicals through a biorefinery. The structure of electron extraction from biomass is that of perovskite. Combined with a photoelectrode, it enables efficient voltage-free photoelectrochemical hydrogen production.
도 1a은 상기한 내용을 구현하는 본 발명의 일 실시예에 따른 수소 생성 장치를 개념적으로 나타낸 도면이고, 도 1b는 도 1a에 도시된 수소 생성 장치에 있어서 제2 전극을 개념적으로 도시한 단면도이며, 도 1c는 도 1a에 도시된 수소 생성 장치를 예시적으로 구현한 것을 나타낸 도면이며, 도 1d는 도 1b의 리그노셀룰로오스를 설명하기 위한 도면이다.FIG. 1A is a diagram conceptually showing a hydrogen generation device according to an embodiment of the present invention that implements the above contents, and FIG. 1B is a cross-sectional view conceptually showing a second electrode in the hydrogen generation device shown in FIG. 1A. , FIG. 1C is a diagram showing an exemplary implementation of the hydrogen generation device shown in FIG. 1A, and FIG. 1D is a diagram for explaining the lignocellulose of FIG. 1B.
도 1a 내지 도 1d를 참조하면, 본 발명의 일 실시예에 따른 수소 생성 장치는, 바이오매스 중 리그노셀룰로오스(LCC)를 분해 또는 산화시켜 분해 생성물을 획득하고, 이때 획득한 전자를 통해 수소를 생산하는 시스템으로서, 전해질 내에 제공되며 서로 전기적으로 연결된 제1 전극(EL1) 및 제2 전극(EL2), 상기 제1 전극(EL1)과 상기 제2 전극(EL2)이 각각 제공된 제1 영역(R1)과 제2 영역(R2), 상기 제2 영역(R2)과 분리된 해중합부(DPP)를 포함하며, 전자전달 매개체(EM)는 제1 영역(R1)과 해중합부(DPP)에 제공된다. 제1 영역(R1)과 제2 영역(R2)은 반투과성 멤브레인(MM)에 의해 구분된다1A to 1D, the hydrogen generation device according to an embodiment of the present invention decomposes or oxidizes lignocellulose (LCC) in biomass to obtain decomposition products, and generates hydrogen through the electrons obtained at this time. A system for producing a first electrode (EL1) and a second electrode (EL2) provided in an electrolyte and electrically connected to each other, and a first region (R1) provided with the first electrode (EL1) and the second electrode (EL2), respectively. ) and a second region (R2), and a depolymerization portion (DPP) separated from the second region (R2), and an electron transfer mediator (EM) is provided to the first region (R1) and the depolymerization portion (DPP). . The first region (R1) and the second region (R2) are separated by a semi-permeable membrane (MM)
본 명세서에 기술된 제1 전극(EL1)은 전자전달 매개체(EM)가 산화하는 작동전극이다. 본 명세서에 기술된 제2 전극(EL2)은 수소가 발생할 수 있는 상대전극이다. 다시 말해, 제1 전극(EL1)은 상기 전자전달 매개체(EM)가 환원되는 애노드일 수 있다. 제1 전극(EL1)은 전자전달 매개체(EM)가 산화되는 캐소드일 수 있다. 본 발명의 일 실시예에 있어서, 설명의 편의를 위해 제1 전극(EL1)과 제2 전극(EL2)으로 이루어진, 작동전극과 상대전극으로 이루어진 2전극 구조를 설명하나, 이에 한정되는 것은 아니며, 기준 전극을 더 포함한 3 전극 구조를 가질 수 있음은 물론이다.The first electrode EL1 described herein is a working electrode in which an electron transport medium (EM) is oxidized. The second electrode EL2 described in this specification is a counter electrode capable of generating hydrogen. In other words, the first electrode EL1 may be an anode where the electron transfer medium (EM) is reduced. The first electrode EL1 may be a cathode where the electron transport medium (EM) is oxidized. In one embodiment of the present invention, for convenience of explanation, a two-electrode structure consisting of a first electrode (EL1) and a second electrode (EL2), a working electrode and a counter electrode is described, but is not limited thereto. Of course, it can have a three-electrode structure further including a reference electrode.
상기 제1 전극(EL1)은, 후술할 전자전달 매개체(EM)를 산화시켜 전자전달 매개체(EM)로부터 전자를 추출하기 위한 것이다.The first electrode EL1 is used to extract electrons from the electron transfer medium (EM) by oxidizing the electron transfer medium (EM), which will be described later.
상기 제1 전극(EL1)은 다양한 도전성 재료로 이루어질 수 있으며 예를 들어, 탄소계 물질을 포함할 수 있다. 상기 탄소계 물질은, 탄소 펠트(carbon felt), 카본지(carbon paper), 환원-산화그래핀 (reduced-graphene oxide, RGO) 적층체, 다공성 탄소물질, 그래핀 구조체, 탄소나노튜브(carbon nano tube) 구조체 등에서 선택된 1종 이상을 포함할 수 있다. 또는 상기 탄소계 물질은 카본 페이퍼(carbon paper), 글래시 카본(glassy carbon), FTO(fluorinetaed tin oxide), ITO(indium tin oxide) 등의 재료를 더 포함할 수도 있다.The first electrode EL1 may be made of various conductive materials and may include, for example, a carbon-based material. The carbon-based material includes carbon felt, carbon paper, reduced-graphene oxide (RGO) laminate, porous carbon material, graphene structure, and carbon nanotube. ) It may include one or more types selected from structures, etc. Alternatively, the carbon-based material may further include materials such as carbon paper, glassy carbon, fluorinetaed tin oxide (FTO), and indium tin oxide (ITO).
그러나 상기 제1 전극(EL1)의 재료는 이에 한정되는 것은 아니며, 다양한 다른 재료로 이루어질 수 있다. 본 발명의 일 실시예에 있어서, 제1 전극(EL1)은 백금 또는 백금을 포함된 전극일 수 있다. 백금과 같은 금속을 포함하지 않는 경우 전극의 제조시 제조 비용이 감소하는 이점이 있을 수 있으며, 백금의 사용시 다른 전극과 다른 전기화학적 이점이 있을 수 있다.However, the material of the first electrode EL1 is not limited to this and may be made of various other materials. In one embodiment of the present invention, the first electrode EL1 may be platinum or an electrode containing platinum. If a metal such as platinum is not included, there may be an advantage in reducing manufacturing costs when manufacturing an electrode, and the use of platinum may have electrochemical advantages that are different from other electrodes.
상기 제2 전극(EL2)은 전자전달 매개체(EM)로부터 추출한 전자를 이용하여 양성자를 환원시킴으로써 수소를 생산하기 위한 것이다.The second electrode EL2 is used to produce hydrogen by reducing protons using electrons extracted from an electron transfer medium (EM).
본 발명의 일 실시예에 있어서, 상기 제2 전극(EL2)은 광음극일 수 있다. 이에 따라, 상기 제2 전극(EL2)은 전극층과 광반응성 물질을 포함하는 광반응층을 포함할 수 있다.In one embodiment of the present invention, the second electrode EL2 may be a photocathode. Accordingly, the second electrode EL2 may include an electrode layer and a photoreactive layer containing a photoreactive material.
상세하게는 제2 전극(EL2)은 태양 전지와 유사한 형태를 갖는 광음극으로 제조될 수 있다. 즉, 제2 전극(EL2)는 태양전지부(SLC)와 이를 커버하는 봉지부를 포함할 수 있다.In detail, the second electrode EL2 may be manufactured as a photocathode having a shape similar to that of a solar cell. That is, the second electrode EL2 may include a solar cell unit SLC and an encapsulation unit covering the solar cell unit SLC.
태양 전지부는 제1 서브전극(SEL1), 광반응층(LAL), 제2 서브전극(SEL2)을 포함할 수 있다. 상기 제1 서브전극(SEL1)과 광반응층(LAL) 사이에는 정공 전달층(HTL)이 더 제공될 수 있으며, 광반응층(LAL)과 제2 서브전극(SEL2) 사이에는 전자 전달층(ETL)이 더 제공될 수 있다. 이에 더해, 광 반응층(LAL)과 전자 전달층(ETL) 사이에는 광반응층(LAL)을 안정화시키고 광반응층(LAL)의 정공과 전자 전달층(ETL) 사이의 계면 재결합을 차단하기 위한 패시베이션층(PSV)이 제공될 수 있다.The solar cell unit may include a first sub-electrode (SEL1), a light reaction layer (LAL), and a second sub-electrode (SEL2). A hole transport layer (HTL) may be further provided between the first sub-electrode (SEL1) and the photo-reactive layer (LAL), and an electron transport layer (HTL) may be provided between the photo-reactive layer (LAL) and the second sub-electrode (SEL2) ETL) may be further provided. In addition, between the light-reactive layer (LAL) and the electron transport layer (ETL), a device is installed to stabilize the photo-reactive layer (LAL) and block interfacial recombination between holes in the photo-reactive layer (LAL) and the electron transport layer (ETL). A passivation layer (PSV) may be provided.
상기 제2 전극(EL2)과 상기 태양전지부(SLC)의 가장자리에는 전해질로부터 제2 전극(EL2)의 내부 구성을 보호하면서도 산화 환원 반응을 최적화하기위한 봉지부가 제공된다. 봉지부는 상기 제2 서브전극(SEL2) 상에 제공된 제1 금속막(FM)과 제1 금속막(FM) 상에 제공된 외부 전극막(OEL)을 포함할 수 있다. 상기 제1 금속막(FM)와 외부 금속막(OEL)은 산성 조건에서 우수한 전기적 연결과 높은 안정성을 제공하는 금속 중에 선택될 수 있다. 본 발명의 일 실시예에 있어서, 상기 제1 금속막(FM)은 필즈 금속일 수 있으며, 외부 금속막은 Ti 또는 Ti-Pt일 수 있다. 상기 각 구성요소의 가장자리에는 상기 제2 전극의 외부를 감싸 보호하는 실런트(SLT)가 제공될 수 있으며, 상기 실런트(SLT)는 산성에 안정적인 절연재, 예를 들어 에폭시 수지 등으로 이루어질 수 있다.Encapsulation portions are provided at the edges of the second electrode EL2 and the solar cell unit SLC to optimize redox reactions while protecting the internal structure of the second electrode EL2 from electrolyte. The encapsulation part may include a first metal film (FM) provided on the second sub-electrode (SEL2) and an external electrode film (OEL) provided on the first metal film (FM). The first metal film (FM) and the outer metal film (OEL) may be selected from metals that provide excellent electrical connection and high stability in acidic conditions. In one embodiment of the present invention, the first metal film FM may be a fields metal, and the external metal film may be Ti or Ti-Pt. A sealant (SLT) may be provided at the edge of each component to protect the outside of the second electrode, and the sealant (SLT) may be made of an acid-stable insulating material, for example, epoxy resin.
여기서, 상기 제2 전극(EL2)은 광반응성 물질, 예를 들어 광촉매를 포함할 수 있다. 상기 광촉매는 상기 서브전극에 코팅의 형태로 제공될 수 있다. 상기 광촉매는 상기 전극층에 제공될 때 투명한 도체 기판 상에 제공될 수도 있다. 여기서 투명하다는 뜻은 가시광선 및/또는 자외선에 대해 투명하다는 것을 의미하며, 다양한 도전성 금속 산화물(예를 들어 ITO; indium tin oxide)로 이루어진 기판일 수도 있다. 상기 광촉매가 사용되는 경우 가시광선이나 자외선 파장 대역의 광에 반응하는 광촉매를 포함할 수 있다. 상기 가시광선은 약 400nm 내지 약 750nm 파장 대역의 광을 포함할 수 있으며, 상기 자외선은 약 10nm 내지 약 400nm 파장 대역의 광을 포함할 수 있다. 가시광선이나 자외선 파장 대역의 광에 반응하는 광촉매를 채용하는 경우, 태양광을 이용한 전기화학적 반응이 가능하다.Here, the second electrode EL2 may include a photoreactive material, for example, a photocatalyst. The photocatalyst may be provided in the form of a coating on the sub-electrode. The photocatalyst may also be provided on a transparent conductive substrate when provided in the electrode layer. Here, transparent means transparent to visible light and/or ultraviolet rays, and may be a substrate made of various conductive metal oxides (for example, ITO; indium tin oxide). When the photocatalyst is used, it may include a photocatalyst that reacts to light in the visible or ultraviolet wavelength range. The visible light may include light in a wavelength band of about 400 nm to about 750 nm, and the ultraviolet ray may include light in a wavelength band of about 10 nm to about 400 nm. If a photocatalyst that reacts to light in the visible or ultraviolet wavelength range is used, an electrochemical reaction using sunlight is possible.
본 발명의 일 실시예에 있어서, 상기 전극층, 예를 들어 제2 서브전극층(SEL2)은 백금족의 금속(백금, 루테늄, 로듐, 파라듐, 오스뮴, 이리듐), 금, 은, 크롬, 철, 납, 티타늄, 망간, 코벨트, 니켈, 몰리브덴, 텅스텐, 알루미늄, 규소, 아연, 주석 및 이들의 합금으로 이루어진 군에서 선택된 1종 이상을 포함할 수 있다.In one embodiment of the present invention, the electrode layer, for example, the second sub-electrode layer (SEL2), is made of a platinum group metal (platinum, ruthenium, rhodium, palladium, osmium, iridium), gold, silver, chromium, iron, and lead. , titanium, manganese, cobelt, nickel, molybdenum, tungsten, aluminum, silicon, zinc, tin, and alloys thereof.
상기 서브전극들과 상기 광반응층(LAL)을 이루는 물질의 선택은 제2 전극(EL2)의 역할에 따라 달리 선택될 수 있다. 본 발명의 일 실시예에 있어서, 상기 제2 전극(EL2)은 수소를 생성하기 위한 것으로서, 제2 전극(EL2)의 각 층은 양성자의 환원 포텐셜을 고려하되 태양광을 용이하게 효율적으로 흡수할 수 있도록 작은 밴드갭을 갖는 물질로 선택할 수 있다.Materials forming the sub-electrodes and the photoreactive layer LAL may be selected differently depending on the role of the second electrode EL2. In one embodiment of the present invention, the second electrode EL2 is for generating hydrogen, and each layer of the second electrode EL2 can easily and efficiently absorb sunlight while considering the reduction potential of protons. A material with a small band gap can be selected to allow for this.
본 발명의 일 실시예에 있어서, 상기 광반응층(LAL)은 페로브스카이트를 포함할 수 있다. 상기 페로브스카이트는 밴드갭이 작은 광흡수체로서, 태양광 플럭스를 보다 효과적으로 활용할 수 있으며 이후 후술할 바이오매스, 특히 리그노셀룰로오스(LCC)를 이용한 태양광의 수소 생산시 필요한 에너지 요구량을 낮추는 역할을 한다. 이를 통해 높은 태양광-수소생산 효율(solar-to-H2 (STH) conversion efficiency) 구현할 수 있다.In one embodiment of the present invention, the photoreactive layer (LAL) may include perovskite. The perovskite is a light absorber with a small band gap, which can utilize solar flux more effectively and plays a role in lowering the energy requirement required for solar hydrogen production using biomass, especially lignocellulose (LCC), which will be described later. . Through this, high solar-to- H2 (STH) conversion efficiency can be achieved.
상기 제1 전극(EL1)과 상기 제2 전극(EL2)은 각각 독립적으로 단일 개 또는 복수 개로 제공될 수 있다. 상기 제1 전극(EL1)과 제2 전극(EL2)은 각각 와이어, 시트나 박막 형태, 또는 메쉬 형태 등 다양한 형상으로 제조될 수 있다.The first electrode EL1 and the second electrode EL2 may be independently provided in single or plural pieces. The first electrode EL1 and the second electrode EL2 may each be manufactured in various shapes such as wire, sheet, thin film, or mesh.
상기 제1 전극(EL1)과 제2 전극(EL2)은 배선 등을 통해 서로 전기적으로 연결되며, 제1 전극(EL1)에서 추출된 전자는 상기 배선을 통해 제2 전극(EL2)으로 제공되며, 상기 제2 전극(EL2)으로 제공된 전자는 양성자와 결합하여 수소를 발생시킨다.The first electrode (EL1) and the second electrode (EL2) are electrically connected to each other through a wire, etc., and electrons extracted from the first electrode (EL1) are provided to the second electrode (EL2) through the wire, Electrons provided to the second electrode EL2 combine with protons to generate hydrogen.
상기 제1 전극(EL1)과 제2 전극(EL2)은 도시된 바와 같이 동일한 용기 내에, 또는 각각의 용기 내에 배치될 수 있다. 제1 전극(EL1)과 제2 전극(EL2)은 전해질 내에 배치된다. 여기서, 상기 전해질은 반투과성 멤브레인(MM)을 사이에 두고 제1 영역(R1)과 제2 영역(R2)으로 나누어질 수 있으며, 상기 제1 영역(R1)에는 제1 전극(EL1)이, 제2 영역(R2)에는 제2 전극(EL2)이 각각 제공된다.The first electrode EL1 and the second electrode EL2 may be disposed in the same container or in separate containers as shown. The first electrode EL1 and the second electrode EL2 are disposed in the electrolyte. Here, the electrolyte may be divided into a first region (R1) and a second region (R2) with a semi-permeable membrane (MM) in between, and the first region (R1) includes a first electrode (EL1), A second electrode EL2 is provided in each of the two regions R2.
상기 제1 전극(EL1)과 상기 제2 전극(EL2)이 제공된 용기에는 전해질이 제공된다. 상기 전해질은 수성 전해질일 수 있다. 상기 제1 전극(EL1)이 제공된 제1 영역(R1) 전자전달 매개체(EM)를 포함하는 전해질이 제공된다. 상기 전해질은 산성 전해질 또는 중성 전해질일 수 있다. 본 발명의 일 실시예에 있어서, 상기 전해질은 pH 2이하, 예를 들면, 2, 1,또는 0의 산성 전해질일 수 있다. 이때, 상기 산성 전해질은, 1 M 이상의 산 용액이며, 상기 산 용액은, HCl, H2SO4, H2SO3, HNO3, HNO2 및 H3PO4로 이루어진 군에서 선택된 1종 이상의 산을 포함할 수 있다.An electrolyte is provided in a container provided with the first electrode EL1 and the second electrode EL2. The electrolyte may be an aqueous electrolyte. An electrolyte including an electron transport medium (EM) in a first region (R1) provided with the first electrode (EL1) is provided. The electrolyte may be an acidic electrolyte or a neutral electrolyte. In one embodiment of the present invention, the electrolyte may be an acidic electrolyte with a pH of 2 or less, for example, 2, 1, or 0. At this time, the acidic electrolyte is an acid solution of 1 M or more, and the acid solution is one or more acids selected from the group consisting of HCl, H 2 SO 4 , H 2 SO 3 , HNO 3 , HNO 2 and H 3 PO 4 may include.
선택적으로, 전자전달 매개체(EM)는 중성 pH 또는 중성 pH부근에서 사용하기에 적절할 수 있다. 일실시형태에서 전해질은 약 3 내지 약 7의 범위의 pH를 가질 수 있다.Alternatively, an electron transfer mediator (EM) may be suitable for use at or near neutral pH. In one embodiment, the electrolyte may have a pH ranging from about 3 to about 7.
상기 반투과성 멤브레인(MM)은 제1 전극(EL1)이 제공된 제1 영역(R1)과 제2 전극(EL2)이 제공된 영역 사이에 전자전달 매개체(EM)가 서로 이동되지 않고 제1 영역(R1)에 머무르도록 전자전달 매개체(EM)의 움직임을 방지하며, 양성자와 같은 다른 이온의 움직임은 허용하는 역할을 한다.The semi-permeable membrane (MM) prevents the electron transfer medium (EM) from moving between the first region (R1) where the first electrode (EL1) is provided and the region where the second electrode (EL2) is provided. It prevents the movement of electron transport media (EM) and allows the movement of other ions such as protons.
본 발명의 일 실시예에 있어서, 반투과성 멤브레인(MM)은 양이온 투과성 멤브레인(MM)일 수 있으며, 예를 들어 양성자 투과성 멤브레인(MM)일 수 있다.In one embodiment of the invention, the semi-permeable membrane (MM) may be a cation-permeable membrane (MM), for example, a proton-permeable membrane (MM).
상기 반투과성 멤브레인(MM)은 상기 전자전달 매개체(EM)를 투과시키지 않을 정도의 불투과성을 가져야 하는 바, 예를 들어, 상기 반투과성 멤브레인(MM)은 분자량 200이상, 500이상 또는 100이상을 가지는 분자에 불투과성인 멤브레인(MM)일 수 있다.The semi-permeable membrane (MM) must have a level of impermeability that does not allow the electron transfer medium (EM) to pass through. For example, the semi-permeable membrane (MM) must contain molecules having a molecular weight of 200 or more, 500 or more, or 100 or more. It may be a membrane (MM) that is impermeable to.
본 발명의 일 실시예에 있어서, 상기 반투과성 멤브레인(MM)은 플루오로폴리머-공중합체계의 설퍼네이티드 테트라플루오로에틸렌를 포함하는 멤브레인(MM)일 수 있다. 본 발명의 일 실시예에 있어서, 상기 반투과성 멤브레인(MM)은 나피온 멤브레인(MM)일 수 있으며, 또는 기능기 치환된 셀룰로오스스 멤브레인(MM)일 수 있다.In one embodiment of the present invention, the semi-permeable membrane (MM) may be a membrane (MM) containing fluoropolymer-copolymer sulfurinated tetrafluoroethylene. In one embodiment of the present invention, the semi-permeable membrane (MM) may be a Nafion membrane (MM), or a functional group-substituted cellulose membrane (MM).
상기 전해질의 제1 영역(R1), 즉, 제1 전극(EL1)이 제공되는 영역과 해중합부(DPP)에는 전자 전달 매개체(EM)가 제공된다.An electron transfer medium (EM) is provided in the first region (R1) of the electrolyte, that is, the region where the first electrode (EL1) is provided and the depolymerization portion (DPP).
상기 전자전달 매개체(EM)는 산화와 환원을 거쳐, 리그노셀룰로오스(LCC)를 분해하고 부가 부산물(VAP)를 생성하며 제1 전극(EL1)에서 산화됨으로써, 제2 전극(EL2)측에 전자를 제공하는 역할을 하는 바, 해중합부(DPP)에서 리그노셀룰로오스(LCC)를 해중합하는 과정에서 환원되고 제1 영역(R1)의 제2 전극(EL2)에서 산화되는 과정을 거친다.The electron transfer medium (EM) goes through oxidation and reduction, decomposes lignocellulose (LCC), generates an addition by-product (VAP), and is oxidized at the first electrode (EL1), thereby transferring electrons to the second electrode (EL2). It serves to provide lignocellulose (LCC) in the depolymerization section (DPP) and is reduced in the process of depolymerizing lignocellulose (LCC) and oxidized in the second electrode (EL2) of the first region (R1).
본 발명의 일 실시예에 있어서, 상기 전자전달 매개체(EM)는 도시된 바와 같이 제1 영역(R1)과 해중합부(DPP)에 제공되며, 제1 영역(R1)과 해중합부(DPP)는 직간접적으로 서로 연결되어 해중합부(DPP)에서 환원된 전자전달 매개체(EM)가 제1 영역(R1)에 제공되며, 제1 영역(R1)에서 산화된 전자전달 매개체(EM)가 해중합부에 다시 제공되는 형태로 순환될 수 있다.In one embodiment of the present invention, the electron transfer mediator (EM) is provided in the first region (R1) and the depolymerization portion (DPP) as shown, and the first region (R1) and the depolymerization portion (DPP) are The electron transfer mediator (EM) reduced in the depolymerization unit (DPP) is directly or indirectly connected to the first region (R1), and the electron transfer mediator (EM) oxidized in the first region (R1) is provided to the depolymerization unit. It can be circulated in a form that provides it again.
본 발명의 일 실시예에 있어서, 전자전달 매개체(EM)는 전자를 받거나 줄 수 있거나 또는 전자 및 양성자를 받거나 줄 수 있다. 이에 따라, 전자전달 매개체(EM)는 환원과 산화 등을 통해 서로 다른 전하를 가지는 두 가지 형태로 표시될 수 있는 바, 환원된 형태의 제1 전자전달 매개체(EM1)와 산화된 형태의 제2 전자전달 매개체 (EM2)로 표시될 수 있다.In one embodiment of the present invention, an electron transfer medium (EM) is capable of receiving or donating electrons, or is capable of receiving or donating electrons and protons. Accordingly, the electron transfer medium (EM) can be expressed in two forms with different charges through reduction and oxidation, with the first electron transfer medium (EM1) in a reduced form and the second electron transfer medium (EM1) in an oxidized form. It can be labeled as an electron transfer medium (EM2).
상기 전자전달 매개체(EM)는 음이온일 수 있으며, 전자전달 매개체(EM)의 산화된 상태의 전하는 -1 보다 작은데, 예를 들면, -2, -3, -4일 수 있다. 본 발명의 일 실시예에 있어서, 산화된 상태는 -3의 전하를 가진다. 본 발명의 일 실시예에 있어서, 일 실시예에 있어서, 전자전달 매개체(EM)의 환원된 상태의 전하는 전자전달 매개체(EM)의 산화된 상태의 전하보다 1 이상 낮은데, 예를 들면 2이상 또는 3이상 낮다. 그러므로, 제2 전자전달 매개체(EM2)가 -3의 전하를 가질 때, 제1 전자전달 매개체(EM1)는 -5의 전하를 가질 수 있다.The electron transfer medium (EM) may be an anion, and the charge in the oxidized state of the electron transfer medium (EM) is less than -1, for example, -2, -3, or -4. In one embodiment of the invention, the oxidized state has a charge of -3. In one embodiment of the invention, in one embodiment, the charge in the reduced state of the electron transfer medium (EM) is at least 1 lower than the charge in the oxidized state of the electron transfer medium (EM), for example at least 2 or It is lower than 3. Therefore, when the second electron transfer medium (EM2) has a charge of -3, the first electron transfer medium (EM1) may have a charge of -5.
전자전달 매개체(EM)는 색깔을 가질 수 있으며 산화나 환원시 서로 다른 색깔을 가질 수 있다. 이 경우, 전자전달 매개체(EM)가 함유된 전해질의 색이 변화하므로, 반응의 진행 여부 및 전자전달 매개체(EM)의 변화 여부를 색깔의 변화로 확인할 수 있다.Electron transfer mediators (EMs) can be colored and can have different colors when oxidized or reduced. In this case, since the color of the electrolyte containing the electron transfer medium (EM) changes, it is possible to check whether the reaction is progressing and whether the electron transfer medium (EM) has changed by changing the color.
본 발명의 일 실시예에 있어서, 전자전달 매개체(EM)는 산화제 역할을 하는 것으로 알려진 금속이온 또는 폴리옥소메탈레이트가 사용될 수 있다. 상기 산화제 역할의 금속 이온으로는 안정한 산화수가 복수이고 강력한 산화제로 알려진 금속의 이온, 예를 들어, Fe나 Ce의 이온을 포함할 수 있다. 상기 금속 이온인 Fe3+나 Ce4+의 경우 바이오매스를 산화 분해시키는 과정에서 전자를 추출되어 Fe2+나 Ce3+로 환원될 수 있으며, 이러한 과정을 통해 중간 매개체로 사용될 수 있다.In one embodiment of the present invention, the electron transfer mediator (EM) may be a metal ion or polyoxometalate known to act as an oxidizing agent. The metal ion serving as the oxidizing agent may include metal ions that have multiple stable oxidation numbers and are known to be strong oxidizing agents, for example, Fe or Ce ions. In the case of the metal ions Fe 3+ or Ce 4+ , electrons are extracted during the oxidative decomposition of biomass and can be reduced to Fe 2+ or Ce 3+ , and through this process, they can be used as intermediate mediators.
상기 폴리옥소메탈레이트는 적어도 2, 3, 6, 7, 12, 18, 24, 30 또는 132개의 금속 원자를 포함할 수 있으며, 주된 금속원자 조성물 및 P, Si, S, Ge, W, V, Mo, Mn, Se, Te, As, Sb, Sn, 및 Ti에서 선택되는 하나 이상의 추가 이종원자 조성물을 포함할 수 있다. 본 발명의 일 실시예에 있어서, 폴리옥소메탈레이트는 주된 금속원자 조성물 및 W, V, Mo, Nb, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sn, Pb, Al, 및 Hg에서 선택되는 하나 이상의 추가 이종원자 조성물을 포함할 수 있다. 본 발명의 일 실시에에 있어서, 일 실시예에 있어서, 폴리옥소메탈레이트 중에 금속원자는 W, Mo, V 및 Nb,및 이의 조합으로 이루어진 군으로부터 선택될 수 있다. 본 발명의 일 실시예에 있어서, 폴리옥소메탈레이트 중에 금속원자는 Mo 및 V, 및 이의 조합으로 이루어진 군으로부터 선택될 수 있으며, 본 발명의 일 실시예에 있어서, 폴리옥소메탈레이트 중에 금속원자는 Mo 원자일 수 있으며, 이 경우 상기 폴리옥소메탈레이트는 포스포몰리브드산(PMA; Phosphomolybdic acid)일 수 있다.The polyoxometalate may contain at least 2, 3, 6, 7, 12, 18, 24, 30 or 132 metal atoms, and the main metal atom composition and P, Si, S, Ge, W, V, It may include one or more additional heteroatom compositions selected from Mo, Mn, Se, Te, As, Sb, Sn, and Ti. In one embodiment of the present invention, the polyoxometalate has a main metal atom composition and W, V, Mo, Nb, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sn, Pb, Al , and Hg. In one embodiment of the present invention, in one embodiment, the metal atom in the polyoxometalate may be selected from the group consisting of W, Mo, V, and Nb, and combinations thereof. In one embodiment of the present invention, the metal atom in the polyoxometalate may be selected from the group consisting of Mo, V, and combinations thereof, and in one embodiment of the present invention, the metal atom in the polyoxometalate is It may be a Mo atom, and in this case, the polyoxometalate may be phosphomolybdic acid (PMA).
본 발명의 일 실시예에 있어서, 존재하는 W, Mo, V 및/또는 Nb에 더하여, 폴리옥소메탈레이트는 추가로 Ti, V, Cr, Mn, Fe, Co, Ni, Cu, 및/또는 Zn를 포함할 수 있다. 존재하는 W, Mo, V 및/또는 Nb에 더하여, 폴리옥소메탈레이트는 추가로 Sn, Pb, Al, 및/또는 Hg를 포함할 수 있다.In one embodiment of the invention, in addition to W, Mo, V and/or Nb present, the polyoxometallate further comprises Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and/or Zn. may include. In addition to W, Mo, V, and/or Nb present, the polyoxometallate may additionally include Sn, Pb, Al, and/or Hg.
일 실시예에 있어서, 폴리옥소메탈레이트는 화학식 [M12O40X]n- 이며 M은 Mo, W 또는 V와 같은 금속, 또는 이의 혼합물이고 X는 P 또는 S이고, n은 적절하게는 3, 4, 5 또는 6이다. 일 실시예에 있어서, 폴리옥소메탈레이트는 화학식 HmM12O40X이고 m은 3, 4, 5 또는 6이고, M은 Mo, W 또는 V와 같은 금속, 또는 이의 혼합물이고 X는 P 또는 Si이다.In one embodiment, the polyoxometalate has the formula [M 12 O 40 , 4, 5 or 6. In one embodiment, the polyoxometallate has the formula H m M 12 O 40 It's Si.
폴리옥소메탈레이트 중에 금속 원자는 같거나 다를 수 있으며, 본 발명의 일실시예에 있어서, 금속원자는 같다.The metal atoms in the polyoxometalate may be the same or different, and in one embodiment of the present invention, the metal atoms are the same.
일 실시예에 있어서, 전자전달 매개체(EM)는 포스포몰리브드산(PMA)일 수 있다. 상기 PMA는 [Mo12PO40]3- 또는 [Mo12PO40]5-, 및 이의 산성 형태, 예를 들면, H3Mo12PO40 또는 H5Mo12PO40일 수 있다. [Mo12PO40]3- 또는 [Mo12PO40]5- , 및 이의 산성 형태, 예를 들면, H3Mo12PO40 또는 H5Mo12PO40는 산화환원 반응을 통해 서로 용이하게 전환가능하다.In one embodiment, the electron transfer mediator (EM) may be phosphomolybdic acid (PMA). The PMA may be [Mo 12 PO 40 ] 3- or [Mo 12 PO 40 ] 5- , and its acidic form, for example, H 3 Mo 12 PO 40 or H 5 Mo 12 PO 40 . [Mo 12 PO 40 ] 3- or [Mo 12 PO 40 ] 5- , and acidic forms thereof, such as H 3 Mo 12 PO 40 or H 5 Mo 12 PO 40 , are easily converted to each other through redox reactions. possible.
PMA는 환원 시 노란색(PMA3-)에서 짙은 녹색(PMA5-)으로의 독특한 색상 변화(특히 700nm에서 흡광도와 함께) 뿐만 아니라 높은 용해도 및 상대적으로 낮은 퍼텐셜에서 가역적 산화환원 거동을 보이기 때문에 바이오매스 해중합을 통한 전자 추출을 위해 적합하다.PMA is a biomass material because it exhibits a unique color change from yellow (PMA 3- ) to dark green (PMA 5- ) upon reduction (particularly with absorbance at 700 nm) as well as high solubility and reversible redox behavior at relatively low potentials. Suitable for electron extraction through depolymerization.
본 발명의 일 실시예에 있어서, 전자전달 매개체(EM)는 리그노셀룰로오스(LCC)를 분해함과 동시에 환원되어 제1 영역(R1)에 제공될 수 있다. 즉, 산화된 형태의 전자전달 매개체(EM)는 리그노셀룰로오스(LCC)의 해중합 반응을 통해 환원되어 제1 전자전달 매개체(EM1)로 변환되며, 이 과정에서 산물로 부가가치가 높은 바닐린, 아세토 바닐론 같은 방향족 화합물, 구아이아콜, 시린골, 시린질 알데하이드, 메틸 시린골, 페닐 아세톤 등과 같은 방향족 지방족 알코올, 및 유기산 등 과 같은 물질이 생성될 수 있다. 예를 들어, 리그노셀룰로오스(LCC)의 해중합 반응을 통해 발생하는 산물로는, 구체적으로, 바닐린(vanillin), 아세토바닐린(acetovanillone), 바닐린 아세톤(vanillyl acetone), 구아이아콜(guaiacol), 4-에틸구아이아콜(4-ethylguaiacol), 4-프로필구아이아콜(4-propyl guaiacol), 2,6-다이메톡시페놀 (2,6-dimethoxyphenol), 4-4-하이드록시-3,5-다이메톡시벤조알데하이드 (hydroxy-3,5-dimethoxybenzaldehyde), 1-(4-하이드록시-3,5-다이메톡시페닐)에탄-1-온)(1-(4-hydroxy-3,5-dimethoxyphenyl)ethan-1-one), 4-하이드록시-3,5-다이메톡시벤조산 (4-hydroxy-3,5-dimethoxybenzoic acid), 페놀(phenol), 1-(4-하이드록시-2-메틸페닐)에탄-1-온 (1-(4-hydroxy-2-methylphenyl)ethan-1-one), 4-하이드록시-3-프로필벤조산(4-hydroxy-3-propylbenzoicacid), 이소부틸 4-하이드록시벤조에이트 (isobutyl 4-hydroxybenzoate), 부틸 4-하이드록시벤조에이트 (butyl 4-hydroxybenzoate), 시링알데하이드 (syringaldehyde ), p-쿠마린산( p-coumaric acid), 3-하이드록시-4-메톡시페닐-에탄온 (3-hydroxy-4-methoxyphenyl-ethanone), 아세토시린원 (acetosyringone), 4-메톡시-3-메틸-페놀 (4-methoxy-3-methylphenol) 등이 있다.In one embodiment of the present invention, the electron transfer mediator (EM) may be reduced while decomposing lignocellulose (LCC) and provided to the first region (R1). In other words, the oxidized form of the electron transfer mediator (EM) is reduced through the depolymerization reaction of lignocellulose (LCC) and converted into the first electron transfer mediator (EM1), and in this process, vanillin and acetobar, which have high added value, are produced as products. Substances such as aromatic compounds such as nilone, aromatic aliphatic alcohols such as guaiacol, syringol, syringyl aldehyde, methyl syringol, phenylacetone, etc., and organic acids may be produced. For example, products generated through the depolymerization reaction of lignocellulose (LCC) include, specifically, vanillin, acetovanillone, vanillyl acetone, guaiacol, 4 -Ethylguaiacol, 4-propyl guaiacol, 2,6-dimethoxyphenol, 4-4-hydroxy-3,5 -Dimethoxybenzoaldehyde (hydroxy-3,5-dimethoxybenzaldehyde), 1-(4-hydroxy-3,5-dimethoxyphenyl)ethan-1-one)(1-(4-hydroxy-3,5 -dimethoxyphenyl)ethan-1-one), 4-hydroxy-3,5-dimethoxybenzoic acid, phenol, 1-(4-hydroxy-2 -methylphenyl)ethan-1-one (1-(4-hydroxy-2-methylphenyl)ethan-1-one), 4-hydroxy-3-propylbenzoic acid (4-hydroxy-3-propylbenzoicacid), isobutyl 4- Hydroxybenzoate (isobutyl 4-hydroxybenzoate), butyl 4-hydroxybenzoate (butyl 4-hydroxybenzoate), syringaldehyde, p-coumaric acid, 3-hydroxy-4-mer These include 3-hydroxy-4-methoxyphenyl-ethanone, acetosyringone, and 4-methoxy-3-methylphenol.
리그노셀룰로오스(LCC)는 바이오매스로서, 셀룰로오스, 헤미셀룰로오스, 리그닌을 포함하여 구성된다. 본 발명의 일 실시예에 있어서, 리그노셀룰로오스(LCC)는 리그닌, 셀룰로오스, 또는 헤미셀룰로오스 중 적어도 하나를 분리하거나 제거하는 공정 등의 전처리 공정이 수행되지 않은 것으로서, 리그닌, 셀룰로오스, 및 헤미셀룰로오스가 분리되지 않은 상태로 결합된 것이다.Lignocellulose (LCC) is a biomass composed of cellulose, hemicellulose, and lignin. In one embodiment of the present invention, lignocellulose (LCC) is one in which a pretreatment process such as a process for separating or removing at least one of lignin, cellulose, or hemicellulose has not been performed, and lignin, cellulose, and hemicellulose are not separated. It is combined in an unsettled state.
일반적으로, 리그노셀룰로오스(LCC)는 가수분해 전처리를 수행하며, 가수분해 전처리 과정에서, 셀룰로오스와 헤미셀룰로오스가 분해되어 당류를 생산하는 주요 탄소원으로 활용되고 있으며, 반면 리그닌은 가수분해를 방해하여 제거되는 물질로 여겨지고 있다.In general, lignocellulose (LCC) undergoes hydrolysis pretreatment, and during the hydrolysis pretreatment, cellulose and hemicellulose are decomposed and used as the main carbon source to produce sugars, while lignin is removed by interfering with hydrolysis. It is considered a substance.
본 발명의 일 실시예에서는, 리그닌, 셀룰로오스, 및 헤미셀룰로오스가 분리되지 않은 상태로 제공되되, 전자전달 매개체(EM)가 리그노셀룰로오스(LCC)의 해중합 과정에서 선택적으로 리그닌을 분해면서 환원되는 것을 특징으로 한다. 여기서, 리그닌의 선택적 분해는 리그닌의 방향족기가 셀룰로오스 및 헤미셀룰로오스의 방향족기 보다 더 높은 에너지를 갖고 더 쉽게 산화되기 때문으로서, 리그노셀룰로오스(LCC) 바이오매스에서 리그닌이 우선적으로 해중합되고, 이러한 과정을 통해 전자와 양성자를 전자전달 매개체(EM)에 전달한다.In one embodiment of the present invention, lignin, cellulose, and hemicellulose are provided in an unseparated state, but the electron transfer mediator (EM) is reduced by selectively decomposing lignin during the depolymerization of lignocellulose (LCC). Do it as Here, the selective decomposition of lignin occurs because the aromatic group of lignin has higher energy and is more easily oxidized than the aromatic group of cellulose and hemicellulose, so lignin is preferentially depolymerized in lignocellulose (LCC) biomass, and through this process Transfers electrons and protons to an electron transfer medium (EM).
본 발명의 일 실시예에 있어서, 본 발명에서는 처리되지 않은 날것의 리그노셀룰로오스(LCC) 바이오매스(예를 들어 참나무)와 그 고분자 성분(즉, 셀룰로오스와 헤미셀룰로오스 및 리그닌)으로부터 전자와 양성자를 추출한다. 리그닌의 방향족기는 셀룰로오스 및 헤미셀룰로오스의 방향족기 보다 더 높은 에너지를 갖고 더 쉽게 산화되기 때문에 리그노셀룰로오스(LCC) 바이오매스에서 리그닌이 우선적으로 해중합되고, 전자와 양성자를 전자전달 매개체, 예를 들어 PMA에 제공한다.In one embodiment of the present invention, electrons and protons are extracted from raw, untreated lignocellulosic (LCC) biomass (e.g., oak) and its polymer components (i.e., cellulose, hemicellulose, and lignin). do. Because the aromatic groups of lignin have higher energy and are more easily oxidized than the aromatic groups of cellulose and hemicellulose, lignin preferentially depolymerizes in lignocellulosic (LCC) biomass and transfers electrons and protons to electron transfer mediators, such as PMA. to provide.
본 발명의 일 실시예는 상술한 구조를 갖는 수소 생성 장치를 이용하여 수소를 생성하는 방법을 포함하며, 상기 수소 생성 방법은 제1 전극(EL1)에서 전자전달 매개체(EM)를 산화시켜 산화된 전자전달 매개체(EM)를 수득하는 단계, 상기 산화된 전자전달 매개체(EM)를 환원시키는 단계, 및 제2 전극(EL2)에서 상기 산화로부터 발생된 전자로 양성자를 환원시켜 수소를 수득하는 단계를 포함한다. 여기서,상기 전자전달 매개체(EM)를 환원시키는 단계는 리그노셀룰로오스(LCC) 바이오매스를 선택적으로 분해하는 과정에서 발생된 전자를 상기 전자전달 매개체(EM)로 전달하는 단계이다.One embodiment of the present invention includes a method of generating hydrogen using a hydrogen generating device having the above-described structure, wherein the hydrogen is generated by oxidizing the electron transport medium (EM) at the first electrode (EL1). Obtaining an electron transfer medium (EM), reducing the oxidized electron transfer medium (EM), and obtaining hydrogen by reducing a proton with an electron generated from the oxidation at a second electrode (EL2). Includes. Here, the step of reducing the electron transfer medium (EM) is a step of transferring electrons generated in the process of selectively decomposing lignocellulose (LCC) biomass to the electron transfer medium (EM).
좀더 상세히 설명하면, 전자전달 매개체(EM)는 리그노셀룰로오스(LCC) 바이오매스의 해중합 시키는 과정에서 환원되어 환원된 전자전달 매개체(EM)(즉, 제1 전자전달 매개체(EM1))로 변환된다. 리그노셀룰로오스(LCC)의 해중합 반응에 있어서, 주요 구성 성분 중 리그닌의 해중합 반응이 우선적으로 일어나며, 리그닌의 분해 반응을 통해 바닐린, 아세토 바닐론 같은 방향족 화합물, 구아이아콜, 시린골, 시린질 알데하이드, 메틸 시린골, 페닐 아세톤 등과 같은 방향족 지방족 알코올, 및 유기산 등과 같은 부가물질(VAP)이 생성될 수 있다.In more detail, the electron transfer medium (EM) is reduced during the depolymerization of lignocellulose (LCC) biomass and converted into the reduced electron transfer medium (EM) (i.e., the first electron transfer medium (EM1)). . In the depolymerization reaction of lignocellulose (LCC), among the main components, the depolymerization reaction of lignin occurs preferentially, and through the decomposition reaction of lignin, aromatic compounds such as vanillin, acetovanillon, guaiacol, syringol, and syringyl aldehyde are produced. , aromatic aliphatic alcohols such as methyl syringol, phenylacetone, etc., and adducts (VAPs) such as organic acids may be generated.
이러한 부가물질(VAP)의 구체적인 예로는, 상술한 바와 같이, 바닐린(vanillin), 아세토바닐린(acetovanillone), 바닐린 아세톤(vanillyl acetone), 구아이아콜(guaiacol), 4-에틸구아이아콜(4-ethylguaiacol), 4-프로필구아이아콜(4-propyl guaiacol), 2,6-다이메톡시페놀 (2,6-dimethoxyphenol), 4-4-하이드록시-3,5-다이메톡시벤조알데하이드 (hydroxy-3,5-dimethoxybenzaldehyde), 1-(4-하이드록시-3,5-다이메톡시페닐)에탄-1-온)(1-(4-hydroxy-3,5-dimethoxyphenyl)ethan-1-one), 4-하이드록시-3,5-다이메톡시벤조산 (4-hydroxy-3,5-dimethoxybenzoic acid), 페놀(phenol), 1-(4-하이드록시-2-메틸페닐)에탄-1-온 (1-(4-hydroxy-2-methylphenyl)ethan-1-one), 4-하이드록시-3-프로필벤조산(4-hydroxy-3-propylbenzoicacid), 이소부틸 4-하이드록시벤조에이트 (isobutyl 4-hydroxybenzoate), 부틸 4-하이드록시벤조에이트 (butyl 4-hydroxybenzoate), 시링알데하이드 (syringaldehyde ), p-쿠마린산( p-coumaric acid), 3-하이드록시-4-메톡시페닐-에탄온 (3-hydroxy-4-methoxyphenyl-ethanone), 아세토시린원(acetosyringone), 4-메톡시-3-메틸-페놀 (4-methoxy-3-methyl-phenol) 등을 들 수 있다.Specific examples of such adducts (VAP) include, as described above, vanillin, acetovanillone, vanillyl acetone, guaiacol, 4-ethylguaiacol (4- ethylguaiacol), 4-propyl guaiacol, 2,6-dimethoxyphenol (2,6-dimethoxyphenol), 4-4-hydroxy-3,5-dimethoxybenzoaldehyde (hydroxy) -3,5-dimethoxybenzaldehyde), 1-(4-hydroxy-3,5-dimethoxyphenyl)ethan-1-one)(1-(4-hydroxy-3,5-dimethoxyphenyl)ethan-1-one ), 4-hydroxy-3,5-dimethoxybenzoic acid, phenol, 1-(4-hydroxy-2-methylphenyl)ethan-1-one (1-(4-hydroxy-2-methylphenyl)ethan-1-one), 4-hydroxy-3-propylbenzoicacid, isobutyl 4-hydroxybenzoate (isobutyl 4- hydroxybenzoate), butyl 4-hydroxybenzoate, syringaldehyde, p-coumaric acid, 3-hydroxy-4-methoxyphenyl-ethanone (3- Examples include hydroxy-4-methoxyphenyl-ethanone, acetosyringone, and 4-methoxy-3-methyl-phenol.
환원된 전자전달 매개체(EM)는 수소 생성 장치내의 제1 영역(R1) 내에 제공되어, 제1 전극(EL1)에서 산화되며 전자를 제1 전극(EL1)에 제공한다.The reduced electron transfer medium (EM) is provided in the first region (R1) in the hydrogen generating device, is oxidized at the first electrode (EL1), and provides electrons to the first electrode (EL1).
제1 전극(EL1)에 제공된 전자는 제1 전극(EL1)과 제2 전극(EL2) 사이에 연결된 배선을 통해 제2 전극(EL2)에 제공되며, 제2 전극(EL2) 상에서 양성자를 환원시킴으로써 수소를 발생시킨다. 이때, 상기 제2 전극(EL2)은 페로브스카이트 기반 광음극으로서, 태양광을 흡수하여 수소의 발생에 필요한 전압을 제공할 수 있다.Electrons provided to the first electrode EL1 are provided to the second electrode EL2 through a wire connected between the first electrode EL1 and the second electrode EL2, and reduce protons on the second electrode EL2. generates hydrogen. At this time, the second electrode EL2 is a perovskite-based photocathode, and can absorb sunlight and provide the voltage necessary for hydrogen generation.
상술한 구조를 갖는 수소 생성 장치는 전처리되지 않는 바이오매스를 이용하면서도 매우 높은 STH 효율을 나타낸다. 이를 좀더 설명하면, 다음과 같다.The hydrogen generation device having the above-described structure exhibits very high STH efficiency while using biomass that is not pretreated. To explain this further, it is as follows.
바이오 매스의 산화로부터 발생된 전자로 양성자를 환원시켜 태양광을 이용하여 수소를 생산하는 기술은 탄소 중립적인 지속가능한 사회를 구현하는데 필요한 최상의 기술 중 하나이다. 하지만, 에너지 집약적인 물 산화 반쪽반응과 종래 무기 광촉매의 열악한 성능은 실제 태양광 수소 생산에 큰 장애물이었다. 그러나, 본 실시예에 따른 수소 생성 장치는 리그노셀룰로오스(LC) 바이오매스를 고성능 유기-무기 할로겐화물 페로브스카이트로 사용해서 태양광-H2 (STH) 변환 효율이 최고 24.4%를 보인 광전자화학 전지를 제시한다. 이에 더해 본 발명의 일 실시예에 따르면, 리그노셀룰로오스 바이오매스에서 리그닌의 선택적 해중합를 통해 바닐린, 아세토 바닐론 같은 방향족 화합물, 구아이아콜, 시린골, 시린질 알데하이드, 메틸 시린골, 페닐 아세톤 등과 같은 방향족 지방족 알코올, 및 유기산 등과 같은 부가가치 화합물을 생산할 수 있다.The technology to produce hydrogen using sunlight by reducing protons with electrons generated from the oxidation of biomass is one of the best technologies needed to realize a carbon-neutral sustainable society. However, the energy-intensive water oxidation half-reaction and the poor performance of conventional inorganic photocatalysts have been major obstacles to actual solar hydrogen production. However, the hydrogen generation device according to this embodiment uses lignocellulose (LC) biomass as a high-performance organic-inorganic halide perovskite and shows a solar-H 2 (STH) conversion efficiency of up to 24.4%. Present the battery. In addition, according to one embodiment of the present invention, aromatic compounds such as vanillin and aceto vanillon, guaiacol, syringol, syringyl aldehyde, methyl syringol, phenyl acetone, etc. are produced through selective depolymerization of lignin in lignocellulosic biomass. Value-added compounds such as aromatic aliphatic alcohols and organic acids can be produced.
특히, 본 발명의 일 실시예에 따르면, 리그닌, 셀룰로오스, 및 헤미셀룰로오스가 서로 결합되어 있는 상태의 리그노셀룰로오스를 사용함에도 불구하고, 전자전달 매개체가 별도의 전처리 등을 거쳐 분리된 리그닌과 상응하는 수준으로 리그노세룰로오스를 해중합시킴과 동시에 환원되는 것에 특징이 있다. 즉, 예를 들어, 동일 발명자의 특허 공개 번호 10-2021-0082686호의 발명에서도 리그닌을 사용한 수소 생산 시스템에 대해 개시하고 있으나, 상기 공지 발명에서의 리그닌은 리그노셀룰로오스로부터 전처리를 통해 별도로 분리한 리그닌을 의미하는 것이며, 전처리를 최소화한 형태, 즉 리그노셀룰로오스를 의미하는 것은 아니다. 또한, 기존 발명에 따르면, 이러한 리그노셀룰로오스는 산화분해 (oxidative depolymerization)하여 리그닌 제거 후 생성되는 당을 효소나 균을 이용하여 발효시켜 바이오연료(바이오 에탄올)로 전환하는 형태로 사용되는 경우가 일반적이기 때문에 별도의 전처리 없이 수소 생산에 이용하는 것은 사실상 어렵다. 이는 리그노셀룰로오스 바이오매스의 낮은 용해도와 분자의 복잡성으로 인해 낮은 리그노셀룰로오스 바이오매스 전환 수율과 낮은 선택성에 기인한 것이다. 이에 더해, 리그닌의 복잡한 구조로 인해 리그닌만 선택적으로 해중합하는 것은 더욱더 어려웠다. 이 때문에 리그노셀룰로오스를 직접적으로 이용하는 바이오 정제는 아직까지 실용성 및 경제성이 부족한 상태이다.In particular, according to one embodiment of the present invention, despite using lignocellulose in which lignin, cellulose, and hemicellulose are bonded to each other, the electron transfer mediator is at a level equivalent to that of lignin separated through separate pretreatment. It is characterized by depolymerizing lignocellulose and reducing it at the same time. That is, for example, the same inventor's patent publication number 10-2021-0082686 also discloses a hydrogen production system using lignin, but the lignin in the above-mentioned known invention is lignin separately separated from lignocellulose through pretreatment. It does not mean a form with minimal pretreatment, that is, lignocellulose. In addition, according to existing inventions, such lignocellulose is generally used in the form of converting the sugar produced after lignin removal through oxidative depolymerization into biofuel (bioethanol) by fermenting it using enzymes or bacteria. Therefore, it is virtually difficult to use it for hydrogen production without separate pretreatment. This is due to the low lignocellulosic biomass conversion yield and low selectivity due to the low solubility and molecular complexity of lignocellulosic biomass. In addition, due to the complex structure of lignin, it was even more difficult to selectively depolymerize only lignin. For this reason, biorefinement using lignocellulose directly is still lacking in practicality and economic feasibility.
이에 더해, 종래 기술에 따르면 비교적 높은 온도(>90 ℃)에서 고도로 처리된 바이오매스 유래 화학물질의 최대 해중합에 초점이 맞춰져 있었으며. 바이오리파이너리를 통해 보다 효율적으로 활용될 수 있는 셀룰로오스와 헤미셀룰로오스도 짧은 사슬지방족 분자로 거의 완전히 해중합되기는 하나 많은 CO2 배출이 이루어졌다.In addition, prior art has focused on maximum depolymerization of highly processed biomass-derived chemicals at relatively high temperatures (>90 °C). Cellulose and hemicellulose, which can be utilized more efficiently through biorefineries, are also almost completely depolymerized into short-chain aliphatic molecules, but produce a lot of CO2 emissions.
본 발명은 이러한 리그노셀룰로오스에 있어서, 리그노셀룰로오스로부터 특정 구성요소를 별도로 분리하거나 제거하지 않은 상태에서 효율적으로 리그닌의 우선적, 또는 선택적 해중합 반응을 이용한다. 즉, 본 발명은 셀룰로오스 및 헤미셀룰로오스의 본래 성질은 유지한채로, 리그노셀룰로오스로부터 리그닌만을 선택적으로 분해할 수 있는 저온/상압/안전한 기술을 제공한다. 리그노셀룰로오스는 식량자원과 충돌이 없는 2세대 바이오매스에로서, 화석연료대신 화학연료를 생산하기 위한 탄소중립적 원재료 활용하기 위한 소위 바이오 리파이너리 기술에 대한 연구가 이루어지고 있음에도, 2010년대 이전 바이오 리파이너리는 셀룰로오스와 헤미셀룰로오스와 같은 다당류로부터 알코올 및 플라스틱 단량체를 생산하는 연구에 한정되었으며, 다당류 유래 화합물질 생산의 낮은 경제성으로 인해 기존에 활용되지 못한 리그닌까지 활용할 수 있는 기술의 개발이 요구되고 있었다. 그러나, 현재까지 리그노셀룰로오스에서 리그닌을 선택적으로 분획 및 해중합 할 수 있는 기술은 환원촉매분획 (reductive catalytic fractionation)이 유일하며, 이 기술은 고온고압에서 폭발성의 수소가스를 활용해야하기 때문에, 스케일업(scale-up), 안정성, 경제성 측면에서 한계가 있다. 그러나, 본 발명에 따르면 리그닌의 추가적인 분획 및 해중합 없이 리그노셀룰로오스로부터 리그닌만을 선택적으로 분해할 수 있는 저온의 상압하에서 안전한 기술을 제공한다.The present invention efficiently uses preferential or selective depolymerization of lignin in lignocellulose without separately separating or removing specific components from lignocellulose. In other words, the present invention provides a low-temperature/normal-pressure/safe technology that can selectively decompose lignin from lignocellulose while maintaining the original properties of cellulose and hemicellulose. Lignocellulose is a second-generation biomass that does not conflict with food resources. Although research is being conducted on so-called biorefinery technology to utilize carbon-neutral raw materials to produce chemical fuels instead of fossil fuels, biorefineries before the 2010s were Research was limited to producing alcohol and plastic monomers from polysaccharides such as cellulose and hemicellulose, and due to the low economic efficiency of producing polysaccharide-derived compounds, there was a demand for the development of technology that could utilize lignin, which had not been utilized previously. However, to date, the only technology that can selectively fractionate and depolymerize lignin from lignocellulose is reductive catalytic fractionation, and because this technology requires the use of explosive hydrogen gas at high temperature and high pressure, scale-up is necessary. There are limitations in terms of scale-up, stability, and economic feasibility. However, according to the present invention, a safe technology is provided at low temperature and normal pressure that can selectively decompose only lignin from lignocellulose without additional fractionation and depolymerization of lignin.
이런 관점에서, 리그노셀룰로오스 바이오매스는 수소 생산에 있어서, 이상적이고 실용적인 대안이 될 수 있다.또한, 본 발명의 일 실시예에 따르면, 광촉매를 별도로 사용할 수 있으나, 기존의 무기 광촉매의 사용 없이 페로브스카이트 광음극을 사용함으로써 바이오매스를 이용한 수소 생산을 용이하게 구현한다. 광촉매, 특히 무기계 광촉매의 경우 광촉매의 낮은 성능은 실용적인 태양광 H2 생산에 있어 또다른 주요 장애물인 바, 기존의 무기 광촉매(예를 들어, TiO2, WO3, BiVO4)는 저렴하고 안정적이나 밴드갭이 비교적 크고(2.4~3.2 eV) 광전자 특성이 좋지 않다. 이러한 본질적인 문제는 태양광의 사용을 근본적으로 제한하고, 외부 바이어스(external bias)를 요구하며, 태양광-H2 (STH) 효율을 상용화 기준(~10%) 보다 훨씬 낮추는 문제가 있다.From this perspective, lignocellulosic biomass can be an ideal and practical alternative for hydrogen production. In addition, according to one embodiment of the present invention, a photocatalyst can be used separately, but the photocatalyst can be used separately without using a conventional inorganic photocatalyst. Hydrogen production using biomass is easily implemented by using a lobskite photocathode. In the case of photocatalysts, especially inorganic photocatalysts, the low performance of photocatalysts is another major obstacle to practical solar H 2 production. Conventional inorganic photocatalysts (e.g., TiO 2 , WO 3 , BiVO 4 ) are inexpensive and stable, but The band gap is relatively large (2.4-3.2 eV) and the optoelectronic properties are poor. These inherent problems fundamentally limit the use of solar power, require external bias, and lower solar-H 2 (STH) efficiency far below the commercialization standard (~10%).
이에 비해 본 발명의 일 실시예에 따르면 제2 전극(음극)으로 페로브스카이트(예를 들어, 할로겐화납 페로브스카이트)를 사용함으로써, 종래의 광촉매에 비해 많은 이점을 제공한다. 예를 들어, 페로브스카이트 전극은 조정 가능한 밴드갭과 에너지 준위, 높은 흡수 계수 및 우수한 전하 수송을 가진다. 그럼에도 불구하고 태양광 수소(H2) 생산을 위한 페로브스카이트 기반 광전극에 대한 보고는 소수에 불과하며 물에 대한 취약성으로 인해 바이오매스 산화와 관련된 보고는 전무하다. 본 발명에서는, 페로브스카이트 기반 광음극과 리그노셀룰로오스 바이오매스를 결합하여 STH 효율이 24.4%인 광전기화학전지를 개시한다.In contrast, according to one embodiment of the present invention, by using perovskite (eg, lead halide perovskite) as the second electrode (cathode), it provides many advantages compared to conventional photocatalysts. For example, perovskite electrodes have tunable bandgaps and energy levels, high absorption coefficients, and excellent charge transport. Nevertheless, there are only a few reports on perovskite-based photoelectrodes for solar hydrogen (H 2 ) production, and there are no reports related to biomass oxidation due to their vulnerability to water. In the present invention, a photoelectrochemical cell with an STH efficiency of 24.4% is disclosed by combining a perovskite-based photocathode and lignocellulose biomass.
본 발명의 일 실시예에서는 바이오매스 산화(<0.8V vs. RHE)를 통한 산화 반쪽 반응의 전위(potential)을 낮추고 페로브스카이트 기반 광음극으로 전체 가시광선 스펙트럼을 수확함으로써 추가적인 바이어스(bias) 및 문제를 일으키는 O2 방출 없이 극적으로 높은 태양광 H2 효율을 달성할 수 있다.In one embodiment of the present invention, additional bias is provided by lowering the potential of the oxidation half-reaction through biomass oxidation (<0.8V vs. RHE) and harvesting the entire visible spectrum with a perovskite-based photocathode. and dramatically higher solar H 2 efficiencies can be achieved without problematic O 2 emissions.
또한, 본 발명의 일 실시예에서는 PMA를 가용성 촉매 및 전자/양성자 매개체로 사용하여 고체 리그노셀룰로오스 바이오매스에서 전자와 양성자를 쉽게 추출하면서 부가 가치가 높은 바닐린, 아세토 바닐론 같은 방향족 화합물, 구아이아콜, 시린골, 시린질 알데하이드, 메틸 시린골, 페닐 아세톤 등과 같은 방향족 지방족 알코올, 유기산 등을 생산할 수 있다.In addition, in one embodiment of the present invention, PMA is used as a soluble catalyst and electron/proton mediator to easily extract electrons and protons from solid lignocellulosic biomass while producing aromatic compounds such as vanillin and aceto-vanillon, which have high added value, and guai. Aromatic aliphatic alcohols such as alcohol, syringol, syringyl aldehyde, methyl syringol, phenylacetone, etc., and organic acids can be produced.
본 발명의 일 실시예에 있어서, 이러한 태양광 수소 생산 장치 및 이를 포함하는 시스템은 눈에 띄는 성능의 저하없이 24 시간 동안 안정적으로 작동할 수 있다. 본 발명의 일 실시예에 따른 수소 생산 장치는 리그노셀룰로오스의 해중합 과정에서 얻은 전자전달 매개체를 통한 전자뿐만 아니라, 태양광의 존재시 태양광에 의한 수소 생산이 가능하기 때문에 바이어스 프리 수소 생산이 가능하며, 이에 더해, 태양광 여부에 따라 다양한 구동이 가능할 수 있다. 예를 들어, 본 발명의 일 실시예에 따른 수소 생성 장치는 태양광의 유무의 따라, 상기 리그노셀룰로오스를 분해하여 상기 전자전달 매개체가 환원되고, 상기 환원된 전자전달 매개체가 산화되며 수소를 생성하는 제1 모드와, 상기 태양광을 흡수하여 수소를 생성하는 제2 모드로 구동될 수 있으며, 제1 모드와 제2 모드 둘다 동시에 구동될 수도 있다. 여기서, 태양광을 비롯한 광 여부에 따라 달라질 수 있으나, 상기 제1 모드는 상기 태양광이 상기 제2 전극에 제공되는 밤에 해당될 수 있고, 상기 제2 모드는 상기 태양광이 상기 제2 전극에 제공되는 낮에 해당될 수 있다.In one embodiment of the present invention, such a solar hydrogen production device and a system including the same can operate stably for 24 hours without any noticeable deterioration in performance. The hydrogen production device according to an embodiment of the present invention is capable of producing hydrogen by solar light in the presence of solar light as well as electrons through an electron transfer mediator obtained during the depolymerization of lignocellulose, thereby enabling bias-free hydrogen production. , In addition, various operations may be possible depending on the availability of solar power. For example, the hydrogen generation device according to an embodiment of the present invention decomposes the lignocellulose, the electron transfer mediator is reduced, and the reduced electron transfer mediator is oxidized to generate hydrogen, depending on the presence or absence of sunlight. It can be driven in a first mode and a second mode that absorbs sunlight to generate hydrogen, and both the first mode and the second mode can be driven simultaneously. Here, it may vary depending on whether or not there is light including sunlight, but the first mode may correspond to a night when the sunlight is provided to the second electrode, and the second mode may correspond to a night when the sunlight is provided to the second electrode. This may apply during the day provided in .
본 발명의 일 실시예에 따른 수소 생산 장치는 상술한 바와 같이 전자전달 매개체를 이용하되 태양광을 이용한 양성자 환원 과정을 거치는 바, 다른 전극에서 산소 생성이 발생하지 않는 산소 발생 프리 반응으로 이루어진다. 이에 따라 산소가 발생함으로써 발생할 수 있는 문제점이 해결된다.As described above, the hydrogen production device according to an embodiment of the present invention uses an electron transfer mediator and undergoes a proton reduction process using sunlight, so that it is an oxygen generation-free reaction in which oxygen generation does not occur at the other electrode. Accordingly, problems that may occur due to oxygen generation are solved.
본 발명의 일 실시예에 따른 수소 생성 장치는 기존의 태양광 H2 생산 및 바이오매스 활용 시스템에 비해 많은 이점을 갖는다. 예를 들어, 우리 바이오매스 광전기화학 시스템은 밤에는 바이오매스 해중합을 통해, 낮에는 STH 전환을 통해 귀중한 화학 물질의 연속적인 생산을 가능하게 한다.The hydrogen generation device according to an embodiment of the present invention has many advantages over existing solar H 2 production and biomass utilization systems. For example, our biomass photoelectrochemical system enables continuous production of valuable chemicals via biomass depolymerization at night and STH conversion during the day.
도 2a는 본 발명의 일 실시예에 따른 바이오매스 광전기화학 시스템의 개념을 도시한 것이며, 도 2b는 본 발명의 일 실시예에 따른 바이어스 광전기화학시스템에 있어서, 낮과 밤의 STH와 PMA의 환원율을 도시한 그래프이다.Figure 2a shows the concept of a biomass photoelectrochemical system according to an embodiment of the present invention, and Figure 2b shows the reduction rates of STH and PMA during the day and night in the bias photoelectrochemical system according to an embodiment of the present invention. This is a graph showing.
도 2a와 도 2b를 참조하면, PMA는 야간에 리그노셀룰로오스 바이오매스의 해중합하며 환원됨으로써 높은 환원율을 나타내며, 낮 동안 H2를 효율적으로 생성하는 데 사용됨으로써, 낮이나 밤 모두 높은 효율로 수소를 생산하였다.Referring to Figures 2a and 2b, PMA exhibits a high reduction rate by depolymerizing and reducing lignocellulosic biomass at night, and is used to efficiently generate H 2 during the day, producing hydrogen with high efficiency both day and night. produced.
여기서, 바이오매스의 해중합은 약 60℃에서 12시간 동안 수행된 것이며, 낮에 해당하는 12시간 동안 모의 태양광의 조사로 수행되었다.Here, the depolymerization of biomass was carried out at about 60°C for 12 hours and irradiated with simulated sunlight for 12 hours, corresponding to daylight.
본 발명의 일 실시예에 따르면, 상기한 도면에서 확인할 수 있는 바와 같이, 본 발명의 경우 낮과 밤에 상관없이 수소를 생산하는 이점을 갖는다. 이에 비해, 기존의 광전기화학 시스템은 낮에만 H2를 생성할 수 있다. 전체 태양광 물분해 장치와 비교하여 본 발명의 바이오매스 광전기화학 장치는 높은 밴드갭 광전극의 엄격한 요구 사항을 완화하고 산화 반쪽 반응의 동역학을 개선하여 보다 효과적으로 STH 변환시킨다. 또한, 바이오매스 광전기화학 시스템은 산화 반쪽 반응을 위해 값비싼 촉매(예를 들어 Ru 및 Ir 기반 촉매)를 사용할 필요도 없고, 여러가지 문제를 유발하는 O2를 생성하지도 않는다.According to one embodiment of the present invention, as can be seen from the above drawing, the present invention has the advantage of producing hydrogen regardless of day or night. In comparison, existing photoelectrochemical systems can generate H 2 only during the day. Compared with the all-solar water splitting device, the biomass photoelectrochemical device of the present invention relaxes the stringent requirements of high bandgap photoelectrodes and improves the kinetics of the oxidation half-reaction, resulting in more effective STH conversion. Additionally, biomass photoelectrochemical systems do not require the use of expensive catalysts (e.g., Ru- and Ir-based catalysts) for the oxidation half-reaction, nor do they generate O 2 , which causes various problems.
더불어, 바이오매스로부터 PMA를 전자전달 매개체로 한 전자와 양성자의 추출은 전극 표면의 직접적인 바이오매스 산화에 비해 실제로 더 유용할 수 있는 데, 대부분의 고분자 바이오매스는 물에 불용성이며 직접 산화는 바이오매스를 비선택적으로 해중합할 수 있다.In addition, extraction of electrons and protons from biomass using PMA as an electron transfer medium may actually be more useful than direct biomass oxidation on the electrode surface. Most polymeric biomass is insoluble in water, and direct oxidation of biomass Can be depolymerized non-selectively.
결론적으로, 본 발명의 일 실시예에 따르면 작은 밴드갭을 갖는 페로브스카이트 기반 광음극과 PMA 매개 바이오매스 산화 반응을 이용함으로써, 태양광으로부터 H2 로의 매우 높은 STH 효율, 예를 들어 20% 이상의 STH 효율을 기록하였다. 이러한 최적화된 조건에서 PMA는 리그노셀룰로오스 바이오매스에서 리그닌을 우선적으로 해중합하고 전자와 양성자를 추출하고 저장할 수 있을 뿐만 아니라 부가가치 화학 물질(즉, 바닐린, 아세토 바닐론 같은 방향족 화합물, 구아이아콜, 시린골, 시린질 알데하이드, 메틸 시린골, 페닐 아세톤 등과 같은 방향족 지방족 알코올, 및 유기산 등)을 생산할 수 있다. 환원된 PMA는 상대적으로 낮은 전위에서 쉽게 재산화될 수 있으며, 따라서 태양광 H2 생산을 위한 전자 및 양성자의 공급원으로서 물을 효과적으로 대체할 수 있다. 바이오매스를 이용한 태양광 H2 생산을 위한 감소된 에너지 요구량은 페로브스카이트와 같은 밴드갭이 낮은 광흡수체가 태양광 플럭스(solar flux)를 보다 효과적으로 활용하고 기록적으로 높은 STH 효율을 얻을 수 있도록 한다.In conclusion, according to one embodiment of the present invention, by using a perovskite-based photocathode with a small bandgap and a PMA-mediated biomass oxidation reaction, very high STH efficiency from sunlight to H 2 , e.g., 20%, is achieved. The above STH efficiency was recorded. Under these optimized conditions, PMA can preferentially depolymerize lignin from lignocellulosic biomass, extract and store electrons and protons, as well as add value-added chemicals (i.e., aromatics such as vanillin, aceto-vanillon, guaiacol, and cyrene). Aromatic aliphatic alcohols such as bone, syringyl aldehyde, methyl syringol, phenylacetone, etc., and organic acids, etc.) can be produced. Reduced PMA can be easily reoxidized at relatively low potentials and can therefore effectively replace water as a source of electrons and protons for solar H 2 production. The reduced energy requirements for solar H2 production from biomass allow low-bandgap light absorbers, such as perovskites, to more effectively utilize solar flux and achieve record-high STH efficiencies. do.
실험예Experiment example
실험에 사용된 재료Materials used in the experiment
리그닌(알칼리계), 포스포몰리브드산(H3PMo12O40, PMA), 질산(≥65%), 황산(95.0% +), 무수 N,N-디메틸포름아미드(DMF), 디메틸 설폭사이드(DMSO), 클로로벤젠, 톨루엔, 메탄올, 에틸 아세테이트, 이소프로판올, 올레일아민 및 폴리(메틸메타크릴레이트)(PMMA)는 Sigma-Aldrich (USA)에서 구입했다. 리그노셀룰로오스(LC) 바이오매스로 전남대학교 이재원 교수팀에서 참나무(> 100 mesh)를 입수했다. 다중벽 탄소 나노튜브(MWCNT, > 95%, OD: 5-15 nm)는 US Research Nanomaterials, Inc 에서 구입했다. 티타늄(Ti) 호일(두께 0.25 um), 필즈 금속(FM; field metal), 요오드화 세슘(CsI) 및 바소쿠프로인(BCP; bathocuproin, 98%)은 Alfa Aesar(미국)에서 구입했다. PTAA(폴리[비스(4-페닐)(2,4,6-트리메틸페닐)아민]) 및 PFNBr(폴리(9,9-비스(3'-(N,N-디메틸)-N-에틸암모늄- 프로필-2,7-플루오렌)-alt-2,7-(9,9-디옥틸플루오렌))디브로마이드)는 각각 Xi'an Polymer Light Technology Corp(중국) 및 1-Material에서 구입했다. Formamidium iodide(FAI) 및 methylammonium bromide(MABr)는 Greatcell Solar Materials(호주)에서 구입했다. 납(II) 요오드화물(PbI2) 및 납(II) 브로마이드(PbBr2)는 Tokyo Chemical Industry(TCI, 일본)에서 구입했다. PC61BM은 EM Index에서 구입했다.Lignin (alkaline), phosphomolybdic acid (H 3 PMo 12 O 40 , PMA), nitric acid (≥65%), sulfuric acid (95.0% +), anhydrous N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), chlorobenzene, toluene, methanol, ethyl acetate, isopropanol, oleylamine, and poly(methyl methacrylate) (PMMA) were purchased from Sigma-Aldrich (USA). As lignocellulose (LC) biomass, oak trees (> 100 mesh) were obtained from Professor Jaewon Lee's team at Chonnam National University. Multi-walled carbon nanotubes (MWCNT, > 95%, OD: 5-15 nm) were purchased from US Research Nanomaterials, Inc. Titanium (Ti) foil (thickness 0.25 μm), field metal (FM), cesium iodide (CsI), and bathocuproin (BCP; bathocuproin, 98%) were purchased from Alfa Aesar (USA). PTAA (poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]) and PFNBr (poly(9,9-bis(3'-(N,N-dimethyl)-N-ethylammonium- Propyl-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene))dibromide) was purchased from Xi'an Polymer Light Technology Corp (China) and 1-Material, respectively. Formidium iodide (FAI) and methylammonium bromide (MABr) were purchased from Greatcell Solar Materials (Australia). Lead(II) iodide (PbI 2 ) and lead(II) bromide (PbBr 2 ) were purchased from Tokyo Chemical Industry (TCI, Japan). PC 61 BM was purchased from EM Index.
바이오매스 산화를 통한 PMA의 환원Reduction of PMA through biomass oxidation
PMA를 0.5M H2SO4 10mL에 0.25M로 용해시켰다. 10분 동안 초음파 처리한 후, 리그닌, 헤미셀룰로오스, 셀룰로오스 또는 리그노셀룰로오스 바이오매스(참나무) 0.375g을 PMA 용액에 첨가한 다음 오일 배스에서 일정한 온도로 인큐베이션하였다. 달리 명시되지 않는 한, PMA와 바이오매스의 혼합 용액을 60℃에서 8시간 동안 인큐베이션했다. 다음 식 1을 사용하여 PMA를 이용해 바이오매스에서 추출된 전자 및 양성자의 수를 계산했다.PMA was dissolved at 0.25M in 10mL of 0.5MH 2 SO 4 . After sonication for 10 min, 0.375 g of lignin, hemicellulose, cellulose, or lignocellulosic biomass (oak) was added to the PMA solution and then incubated at a constant temperature in an oil bath. Unless otherwise specified, the mixed solution of PMA and biomass was incubated at 60°C for 8 hours. The number of electrons and protons extracted from biomass using PMA was calculated using Equation 1 below.
[식 1][Equation 1]
리그닌 1g당 전자 및 양성자의 몰 = Moles of electrons and protons per gram of lignin =
Figure PCTKR2022016118-appb-img-000001
Figure PCTKR2022016118-appb-img-000001
여기서 n은 산화환원 반응에 참여하는 전자의 수(PMA3-에서 PMA5-로 환원시 2); C PMA는 PMA의 몰농도; V PMA 는 PMA 용액의 부피; f red 는 환원된 PMA의 비율; m lignin 은 전자 추출에 사용된 리그닌의 질량이다. f red 값은 Beer-Lambert 법칙을 사용하여 700 nm에서 흡광도를 측정하여 결정되었다. PMA (E a)에 의한 바이오매스 산화에 대한 활성화 에너지는 아레니우스 식에 따른 온도 의존 동역학(temperature-dependent kinetics)을 사용하여 결정되었다.where n is the number of electrons participating in the redox reaction (2 when reducing PMA 3- to PMA 5- ); C PMA is the molar concentration of PMA; V PMA is the volume of PMA solution; f red is the ratio of reduced PMA; m lignin is the mass of lignin used for electron extraction. The f red value was determined by measuring the absorbance at 700 nm using the Beer-Lambert law. The activation energy for biomass oxidation by PMA ( E a ) was determined using temperature-dependent kinetics according to the Arrhenius equation.
Figure PCTKR2022016118-appb-img-000002
Figure PCTKR2022016118-appb-img-000002
k는 일 반응에서의 비례상수; R은 기체상수; T는 반응온도; 그리고 A는 전-지수(pre-exponential) 인자이다. k is the proportionality constant in one reaction; R is the gas constant; T is reaction temperature; And A is a pre-exponential factor.
분석방법Analysis method
V-730 UV/vis 분광광도계(JASCO, 일본)를 사용하여 PMA 용액의 UV/가시광선 흡광도 스펙트럼을 측정했다. 리그닌, 헤미셀룰로오스, 셀룰로오스 및 리그노셀룰로오스 바이오매스의 분광 분석은 670/620 푸리에 변환 적외선(FT-IR) 분광기(Agilent, 미국) 및 VNMRS 600 핵자기공명(NMR) 분광기(Agilent, USA)를 사용하여 수행되었다. 페로브스카이트 태양 전지의 광전지 특성은 AM 1.5G(100mW cm-2) 조명 하에서 Keithley 2401 source 장치를 사용하여 Class AAA Oriel Sol3A 태양광 시뮬레이터(Newport, 미국)에 의해 기록되었다. 스펙트럼 불일치는 KG-5 필터로 덮인 모노실리콘 검출기를 사용하여 보정되었다. 페로브스카이트 태양전지의 광학적 특성은 440 nm의 여기 파장(excitation wavelength)에서 V-670 UV/vis spectrometer(JASCO, Japan)와 Varian Cary Eclipse Fluorescent spectrometer(Agilent, USA)를 사용하여 측정하였다. 에너지 분산형 X선 분광기가 장착된 NOVA Nano 주사전자현미경(SEM)(FEI, USA)을 이용하여 리그노셀룰로오스 바이오매스의 구조, 페로브스카이트 필름의 단면 이미지 및 Ti 호일 위의 백금 나노입자의 형태를 관찰하였다. ESCALAB 250XI UV 광전자 분광계(Thermo Fisher Scientific, USA)를 사용하여 페로브스카이트 박막의 UPS 스펙트럼을 얻었다. Ti 호일 위의 Pt 나노입자는 JEM 2100 투과전자현미경(JEOL, Japan)을 사용하여 분석하였다.The UV/visible absorbance spectrum of the PMA solution was measured using a V-730 UV/vis spectrophotometer (JASCO, Japan). Spectroscopic analysis of lignin, hemicellulose, cellulose and lignocellulosic biomass was performed using a 670/620 Fourier transform infrared (FT-IR) spectrometer (Agilent, USA) and a VNMRS 600 nuclear magnetic resonance (NMR) spectrometer (Agilent, USA). carried out. The photovoltaic properties of the perovskite solar cells were recorded by a Class AAA Oriel Sol3A solar simulator (Newport, USA) using a Keithley 2401 source device under AM 1.5 G (100 mW cm -2 ) illumination. Spectral discrepancies were corrected using a monosilicon detector covered with a KG-5 filter. The optical properties of the perovskite solar cell were measured using a V-670 UV/vis spectrometer (JASCO, Japan) and a Varian Cary Eclipse Fluorescent spectrometer (Agilent, USA) at an excitation wavelength of 440 nm. The structure of lignocellulosic biomass, cross-sectional images of perovskite films, and platinum nanoparticles on Ti foil were examined using a NOVA Nano scanning electron microscope (SEM) equipped with an energy-dispersive X-ray spectrometer (FEI, USA). The shape was observed. UPS spectra of perovskite thin films were obtained using an ESCALAB 250XI UV photoelectron spectrometer (Thermo Fisher Scientific, USA). Pt nanoparticles on Ti foil were analyzed using a JEM 2100 transmission electron microscope (JEOL, Japan).
바닐린 및 아세토바닐론의 추출 및 정량화Extraction and quantification of vanillin and acetovanillone
리그닌과 리그노셀룰로오스 바이오매스의 산화적 해중합으로 바닐린과 아세토바닐론이 생성되었다. PMA 용액을 60℃에서 리그닌 또는 리그노셀룰로오스 바이오매스와 함께 인큐베이션하고, 여과하여 불용성 응집체를 제거하고, 클로로포름과 1:1 부피비로 혼합하여 방향족 화합물을 추출하였다. 파지 분리(phage separation)가 발생하면 1μL의 n-데칸을 2mL의 클로로포름 용액에 가스 크로마토그래피-질량 분석법(GC-MS)의 내부 표준으로 추가하여 바닐린 및 아세토바닐론과 같은 방향족 화합물을 식별하고 정량화했다. GC-MS 스펙트럼은 450-GC 가스 크로마토그래프와 Rtx-5MS 모세관 컬럼(30 m Ｘ 0.25 mm Ｘ 0.25 mm; Restek)이 장착된 320-MS 질량분석기(Bruker, USA)로 측정하였다. 분할 주입(1μL)은 He을 운반 기체로 사용하여 25:1의 분할 비율로 GC Pal 자동 시료 주입기(CTC Analytics AG, Switzerland)로 수행되었다.Oxidative depolymerization of lignin and lignocellulosic biomass produced vanillin and acetovanillone. The PMA solution was incubated with lignin or lignocellulosic biomass at 60°C, filtered to remove insoluble aggregates, and mixed with chloroform at a 1:1 volume ratio to extract aromatic compounds. Once phage separation has occurred, add 1 μL of n-decane to 2 mL of chloroform solution as an internal standard for gas chromatography-mass spectrometry (GC-MS) to identify and quantify aromatic compounds such as vanillin and acetovanillon. did. GC-MS spectra were measured with a 320-MS mass spectrometer (Bruker, USA) equipped with a 450-GC gas chromatograph and an Rtx-5MS capillary column (30 m × 0.25 mm × 0.25 mm; Restek). Split injections (1 μL) were performed with a GC Pal autosampler (CTC Analytics AG, Switzerland) at a split ratio of 25:1 using He as the carrier gas.
페로브스카이트 태양전지 제작Perovskite solar cell production
패터닝된 ITO 기판을 각각 20분 동안 아세톤과 이소프로판올의 초음파 수조에서 세척하였다. 사전 세척된 기판을 오븐에서 건조하고 UV/오존으로 30분 동안 처리했다. 이어서, ITO 기판을 H2O 및 O2가 0.1ppm 미만으로 함유된 N2가 채워진 글로브 박스로 옮겼다. 정공수송층으로 PTAA 용액(2 mg mL-1 톨루엔 용액)을 6000rpm에서 30초 동안 스핀 캐스팅한 다음 100℃에서 15분 동안 가열했습니다. 실온으로 식힌 후, PFN-Br 용액(0.4 mg mL-1 메탄올 용액)을 PTAA/ITO 필름에 형성하였다. 삼중 양이온 페로브스카이트 전구체 용액은 DMF/DMSO(4/1, v/v) 혼합 용액 1mL에 CsI (0.06 M), FAI (1 M), MABr (0.2 M), PbI2 (1.1 M), 및 PbBr2 (0.2 M)를 녹여 준비했다. 페로브스카이트 층의 결정 배향을 증가시키기 위해 미량의 올레일아민(0.1wt%)을 전구체에 첨가하였다. 페로브스카이트 층을 형성하기 위해 1000rpm에서 10초, 5000rpm에서 30초 동안 2단계 스핀 코팅 절차가 채택되었다. 두 번째 단계에서 반용매(anti-solvent) 클로로벤젠 200μL를 회전 과정이 끝나기 15초 전에 중앙에 빠르게 떨어뜨렸다. 얻어진 연갈색 필름을 100℃에서 30분 동안 어닐링하였다. 표면 패시베이션 처리를 위해 PMMA(0.5mg mL-1 에틸 아세테이트)를 필름 위에 떨어뜨리고 5000rpm에서 스핀 코팅한 다음 100℃에서 5분 동안 가열했다. 전자수송층은 PC61BM 용액(25 mg mL-1 클로로벤젠을 1000 rpm에서 30초 동안, BCP를 이소프로필 알코올 용액(1 mg mL-1)에서 4000 rpm에서 30초 동안 스핀-캐스팅하여 형성되었다. 마지막으로, 150nm 두께의 Ag 전극은 < 10-6 Torr에서 열 증착을 통해 증착되었다.The patterned ITO substrate was washed in an ultrasonic bath of acetone and isopropanol for 20 minutes each. The pre-cleaned substrates were dried in an oven and treated with UV/ozone for 30 min. Then, the ITO substrate was transferred to a glove box filled with H 2 O and N 2 containing less than 0.1 ppm of O 2 . As the hole transport layer, PTAA solution (2 mg mL -1 toluene solution) was spin-cast at 6000 rpm for 30 s and then heated at 100 °C for 15 min. After cooling to room temperature, the PFN-Br solution (0.4 mg mL -1 methanol solution) was formed on the PTAA/ITO film. The triple cationic perovskite precursor solution consisted of CsI (0.06 M), FAI (1 M), MABr (0.2 M), PbI 2 (1.1 M), and 1 mL of DMF/DMSO (4/1, v/v) mixed solution. and PbBr 2 (0.2 M) were dissolved and prepared. A trace amount of oleylamine (0.1 wt%) was added to the precursor to increase the crystal orientation of the perovskite layer. A two-step spin coating procedure was adopted to form the perovskite layer, at 1000 rpm for 10 s and at 5000 rpm for 30 s. In the second step, 200 μL of anti-solvent chlorobenzene was quickly dropped into the center 15 seconds before the end of the rotation process. The obtained light brown film was annealed at 100°C for 30 minutes. For surface passivation treatment, PMMA (0.5 mg mL -1 ethyl acetate) was dropped on the film, spin-coated at 5000 rpm, and heated at 100 °C for 5 min. The electron transport layer was formed by spin-casting PC 61 BM solution (25 mg mL -1 chlorobenzene at 1000 rpm for 30 seconds and BCP in isopropyl alcohol solution (1 mg mL -1 ) at 4000 rpm for 30 seconds. Finally, 150 nm thick Ag electrodes were deposited via thermal evaporation at <10 -6 Torr.
태양광 수소 생산을 위한 페로브스카이트 광음극 제작Fabrication of perovskite photocathode for solar hydrogen production
페로브스카이트 광음극은 O2 <0.1 ppm, H2O <0.1 ppm이고, N2가 지속적으로 공급되는 글로브 박스 내부의 페로브스카이트 태양광 전지를 기반으로 제작되었다. 2.5 cm Ｘ 2.5 cm 페로브스카이트 태양 전지를 다이아몬드 커터 칼을 사용하여 4개의 전지로 절단하였다. 그런 다음 각 셀의 활성 영역을 0.3cm Ｘ 0.3cm의 FM 막대로 덮고 70℃에서 2분 동안 가열했다. 전자빔 증발에 의해 Ti 호일에 증착 된 20 nm의 Pt 나노입자로 제조된 Pt-Ti 호일은 FM이 녹으면 태양 전지 상에 부착되었다. 가장자리는 에폭시(J-B Weld, USA)로 밀봉되고(encapsulated), 구리선은 페로브스카이트 태양전지의 제2 전극에 부착되었다. 준비된 페로브스카이트 광음극을 실온에서 12시간 동안 둬서 에폭시 실런트(epoxy sealant)를 건조시켰다.The perovskite photocathode has O 2 <0.1 ppm, H 2 O <0.1 ppm, and was manufactured based on a perovskite solar cell inside a glove box where N 2 is continuously supplied. A 2.5 cm x 2.5 cm perovskite solar cell was cut into four cells using a diamond cutter knife. Then, the active area of each cell was covered with a 0.3 cm × 0.3 cm FM rod and heated at 70°C for 2 min. A Pt-Ti foil made of 20 nm Pt nanoparticles deposited on the Ti foil by electron beam evaporation was attached on the solar cell once FM was melted. The edges were encapsulated with epoxy (JB Weld, USA), and the copper wire was attached to the second electrode of the perovskite solar cell. The prepared perovskite photocathode was left at room temperature for 12 hours to dry the epoxy sealant.
전기화학적 특성Electrochemical properties
SP-150 Biologic potentiostat(BioLogic Science Instruments, France)를 사용하여 선형 스위프 전압전류법(LSV) 및 크로노암페로메트리(CA)를 수행했다. 미리 환원된 PMA의 산화는 MWCNT 페이퍼 (0.5 Ｘ 2 cm), Ag/AgCl 및 Pt 와이어를 각각 작동 전극, 기준 전극 및 상대 전극으로 사용하여 수행되었다. CA 및 가스 크로마토그래피(GC) 분석은 음극에서 재산화된 PMA의 환원을 방지하기 위해 나피온 멤브레인(반투과성 멤브레인에 해당)에 의해 분리된 2개의 구획 있는 H-Cell을 사용하여 수행되었다. 음극 및 양극 구획은 각각 0.5M H2SO4와 0.5M H2SO4의 바이오매스에 의해 미리 환원된 0.25M PMA로 채워졌다. 음극에서 양성자와 PMA 환원 간의 경쟁을 방지하기 위해 나피온 멤브레인은 양극 및 음극 반쪽 전지를 분리한다. 포텐셜(Potentials) vs. Ag/AgCl은 다음 식 2을 사용하여 포텐셜 vs. RHE로 변환되었다.Linear sweep voltammetry (LSV) and chronoamperometry (CA) were performed using a SP-150 Biologic potentiostat (BioLogic Science Instruments, France). Oxidation of pre-reduced PMA was performed using MWCNT paper (0.5 × 2 cm), Ag/AgCl, and Pt wire as working, reference, and counter electrodes, respectively. CA and gas chromatography (GC) analyzes were performed using an H-Cell with two compartments separated by a Nafion membrane (equivalent to a semipermeable membrane) to prevent reduction of reoxidized PMA at the cathode. The cathode and anode compartments were filled with 0.25M PMA pre-reduced by biomass of 0.5MH 2 SO 4 and 0.5MH 2 SO 4 , respectively. To prevent competition between protons and PMA reduction at the cathode, the Nafion membrane separates the anode and cathode half cells. Potentials vs . Ag/AgCl is calculated as potential vs . using Equation 2: Converted to RHE.
[식 2][Equation 2]
E (V vs. RHE) = E (V vs. Ag/AgCl) + 0.0592 Ｘ pH + 0.197E (V vs. RHE) = E (V vs. Ag/AgCl) + 0.0592
광전기화학적 특성Photoelectrochemical properties
광전기화학 분석은 광음극, Pt 와이어 및 Ag/AgCl(1M KCl)을 각각 작동전극, 상대전극 및 기준 전극으로 사용하는 3전극 구성에서 수행되었다. 바이어스가 없는(bias-free) 광전기화학 셀은 다음 조건에서 직접 제조한 2구획 셀(즉 제1 영역과 제2 영역을 갖는 셀)에서 테스트되었다. 제2 영역에 해당하는 음극 구획에서는 제2 전극으로 페로브스카이트 광음극이 제공되었으며 0.5M H2SO4로 채워졌고, 제1 영역에 해당하는 양극 구획에서는 제1 전극으로 MWCNT 페이퍼 전극이 제공되었으머 0.5M H2SO4의 바이오매스에 의해 미리 환원된 0.25M PMA로 채워졌다. 나피온 멤브레인은 제1 영역과 제2 영역의 두 구획을 분리했다. 태양광에 해당하는 광으로는 AM 1.5G 필터(100mW cm-2)가 장착된 300W Xe 램프를 가시광원으로 사용했다. GC 분석을 위한 샘플은 시린지를 사용하여 밀폐된 H-cell의 헤드스페이스로부터 수집되고 GC-2010 Plus 가스 크로마토그래프(Shimadzu Co., Japan)로 분석되었다. 페로브스카이트 광음극의 입사 광자-전자 변환(IPCE) 효율은 20nm 대역폭 모노크로메이터가 장착된 300W 크세논 램프를 사용하여 확인되었다.Photoelectrochemical analysis was performed in a three-electrode configuration using the photocathode, Pt wire, and Ag/AgCl (1 M KCl) as the working, counter, and reference electrodes, respectively. A bias-free photoelectrochemical cell was tested in a homemade two-compartment cell (i.e., a cell with a first region and a second region) under the following conditions: In the cathode compartment corresponding to the second region, a perovskite photocathode was provided as the second electrode and filled with 0.5MH 2 SO 4 , and in the anode compartment corresponding to the first region, a MWCNT paper electrode was provided as the first electrode. It was filled with 0.25M PMA pre-reduced by biomass of 0.5MH 2 SO 4 . The Nafion membrane separated two compartments, the first and second regions. For light equivalent to sunlight, a 300W Xe lamp equipped with an AM 1.5G filter (100mW cm -2 ) was used as a visible light source. Samples for GC analysis were collected from the headspace of the sealed H-cell using a syringe and analyzed with a GC-2010 Plus gas chromatograph (Shimadzu Co., Japan). The incident photon-electron conversion (IPCE) efficiency of the perovskite photocathode was confirmed using a 300 W xenon lamp equipped with a 20 nm bandwidth monochromator.
리그노셀룰로오스 바이오매스의 전자 추출 및 선택적 해중합Electron extraction and selective depolymerization of lignocellulosic biomass.
상술한 방법을 이용하여, 바이오매스 기반 태양광 H2 생산 시스템을 개발하기 위해 먼저 다양한 바이오매스로부터 전자와 양성자의 추출을 조사했다.Using the above-described method, the extraction of electrons and protons from various biomass was first investigated to develop a biomass-based solar H 2 production system.
도 3 및 도 4a 내지 도 4g는 전자전달 매개체로서 PMA가 존재할 때 25, 50, 60, 70 및 90℃의 다양한 온도에서 바이오매스가 인큐베이션되었을 때의 결과를 나타낸 도면들이다.Figures 3 and 4a to 4g are diagrams showing the results when biomass was incubated at various temperatures of 25, 50, 60, 70 and 90°C in the presence of PMA as an electron transfer mediator.
도 3은 60℃에서 8시간 동안 리그노셀룰로오스 바이오매스, 리그닌, 헤미셀룰로오스, 및 셀룰로오스의 각각의 산화를 통한 PMA 환원 UV/Vis 스펙트럼이다.Figure 3 is a UV/Vis spectrum of PMA reduction through respective oxidation of lignocellulosic biomass, lignin, hemicellulose, and cellulose at 60°C for 8 hours.
도 4a 내지 도 4g는 다양한 바이오매스의 산화를 이용하여 PMA3-에서 PMA5-로의 환원한 결과를 도시한 것으로서, 도 4a내지 도 4e는 각각 순서대로 25℃, 50℃, 60℃, 70℃, 90 ℃에서 LC 바이오매스, 리그닌, 헤미셀룰로오스 및 셀룰로오스 산화와 함께 인큐베이트된 PMA 용액의 UV/Vis 흡광도 스펙트럼이며, 도 4f는 700 nm에서 UV/Vis 흡광도를 기반으로 계산된 PMA 환원에 대한 바이오매스 유형 및 인큐베이션 온도의 영향을 나타낸 것이며, 도 4g는 다양한 온도에서 다양한 바이오매스와 함께 인큐베이트된 PMA 용액의 사진이다. 도 4f에 있어서, 100%보다 높은 환원도는 PMA가 2개 이상의 전자와 양성자로 환원을 겪었음을 의미하며, 도 4g에 있어서 PMA 용액은 명확한 차이를 나타내기 위해 0.05M으로 희석되었다.Figures 4a to 4g show the results of reduction from PMA 3- to PMA 5- using oxidation of various biomass, and Figures 4a to 4e show the results at 25°C, 50°C, 60°C, and 70°C in that order, respectively. , UV/Vis absorbance spectra of PMA solutions incubated with LC biomass, lignin, hemicellulose and cellulose oxidation at 90 °C, Figure 4f is the biomass for PMA reduction calculated based on UV/Vis absorbance at 700 nm. The effect of type and incubation temperature is shown, and Figure 4g is a photograph of PMA solutions incubated with various biomass at various temperatures. In Figure 4f, a reduction degree higher than 100% means that PMA underwent reduction to two or more electrons and a proton, and in Figure 4g, the PMA solution was diluted to 0.05M to show a clear difference.
도 3 및 도 4a 내지 도 4g에서 확인할 수 있는 바와 같이, 알칼리 리그닌과 리그노셀룰로오스 바이오매스는 이 전체 온도 범위(60℃ 이상에서 실질적으로 의미 있음)에서 쉽게 산화되어 PMA에게 전자와 양성자를 제공할 수 있는 반면, 셀룰로오스와 헤미셀룰로오스는 90℃ 이상에서만 산화될 수 있었다.As can be seen in Figures 3 and 4a-g, alkaline lignin and lignocellulosic biomass are readily oxidized over this entire temperature range (practically significant above 60°C), providing electrons and protons to PMA. On the other hand, cellulose and hemicellulose could only be oxidized above 90℃.
도 5는 본 발명의 일 실시예에 따른 리그노셀룰로오스 바이오매스, 리그닌, 헤미셀룰로오스 및 셀룰로오스에 의한 PMA 환원의 계산된 활성화 에너지를 나타낸 것이다. 여기서, 활성화 에너지는 아레니우스 식에 따라 계산된 것으로서, 도 5 및 아레니우스 식에 따르면, 리그닌, 셀룰로오스, 헤미셀룰로오스 및 리그노셀룰로오스 바이오매스의 산화에 의한 PMA 환원의 활성화 에너지는 각각 24, 102, 79, 47 kJ mol-1(0.249, 1.057, 0.819, and 0.487 eV)이었다.Figure 5 shows the calculated activation energy of PMA reduction by lignocellulosic biomass, lignin, hemicellulose, and cellulose according to an embodiment of the present invention. Here, the activation energy is calculated according to the Arrhenius equation. According to Figure 5 and the Arrhenius equation, the activation energy of PMA reduction by oxidation of lignin, cellulose, hemicellulose, and lignocellulose biomass is 24 and 102, respectively. , 79, 47 kJ mol -1 (0.249, 1.057, 0.819, and 0.487 eV).
도 6a 및 도 6b는 LC 바이오매스와 반응 시 PMA의 환원를 보여주는 프로파일로서, 도 6a는 LC 바이오매스 산화와 함께 사전 인큐베이트된(preincubated) PMA 용액의 UV/Vis 흡광도 스펙트럼이며, 도 6b는 LC 바이오매스에 의해 환원된 PMA양 및 전자 추출량이다. 도 6a에 있어서, PMA(0.25 M)와 바이오매스(37.5 mg mL-1)의 혼합 용액을 다양한 반응 시간 동안 60℃에서 인큐베이션했다.Figures 6A and 6B are profiles showing the reduction of PMA upon reaction with LC biomass, Figure 6A is a UV/Vis absorbance spectrum of a PMA solution preincubated with LC biomass oxidation, and Figure 6B is a UV/Vis absorbance spectrum of a PMA solution preincubated with LC biomass oxidation. This is the amount of PMA reduced by the mass and the amount of electrons extracted. In Figure 6a, a mixed solution of PMA (0.25 M) and biomass (37.5 mg mL -1 ) was incubated at 60 °C for various reaction times.
도 7a 및 도 7b는 60℃에서 PMA를 사용하여 다양한 바이오매스에서 전자의 추출을 도시한 것으로서, 도 7a는 60 ℃에서 리그닌, 헤미셀룰로오스, 셀룰로오스 산화에 의한 PMA 환원율(%)를 나타낸 것이며, 도 7b는 리그닌, 헤미셀룰로오스, 셀룰로오스 산화의 단위 질량당 추출된 전자의 양을 나타낸 것이다.Figures 7a and 7b show the extraction of electrons from various biomass using PMA at 60°C. Figure 7a shows the PMA reduction rate (%) by oxidation of lignin, hemicellulose, and cellulose at 60°C, and Figure 7b represents the amount of electrons extracted per unit mass of lignin, hemicellulose, and cellulose oxidation.
도 6a 및 도 6b, 그리고, 도 7a 및 도 7b를 참조하면, 60 ℃에서 리그닌과 리그노셀룰로오스 바이오매스에 의한 PMA 환원 정도는 최대 12시간의 인큐베이션 시간과 함께 선형적으로 증가했다. 8시간 후, PMA는 리그닌 및 리그노셀룰로오스 바이오매스에서 각각 7.9 및 6.9mmol/g의 전자(및 양성자)를 추출했다. 이러한 결과는 리그닌이 리그노셀룰로오스 바이오매스에서도 전자와 양성자의 주요 공급원이며 리그닌이 리그노셀룰로오스 바이오매스의 다른 고분자 구성요소(즉, 셀룰로오스 및 헤미셀룰로오스)보다 우선적으로 해중합될 수 있음을 나타낸 것이다.6A and 6B, and 7A and 7B, the extent of PMA reduction by lignin and lignocellulosic biomass at 60 °C increased linearly with incubation times up to 12 hours. After 8 hours, PMA extracted 7.9 and 6.9 mmol/g of electrons (and protons) from lignin and lignocellulosic biomass, respectively. These results indicate that lignin is a major source of electrons and protons in lignocellulosic biomass and that lignin can be depolymerized preferentially over other polymer components (i.e., cellulose and hemicellulose) of lignocellulosic biomass.
PMA에 의한 바이오매스의 완전하고 비선택적인 해중합의 가능성을 배제하기 위해 본 발명에서는 60℃에서 8시간 동안 PMA와 반응하기 전과 후에 다양한 분석 방법을 사용하여 각 바이오매스의 불용성 및 가용성 잔여물을 분석했다.In order to exclude the possibility of complete and non-selective depolymerization of biomass by PMA, the present invention analyzed the insoluble and soluble residues of each biomass using various analytical methods before and after reaction with PMA at 60°C for 8 hours. did.
도 8은 60℃에서 8시간 동안 PMA에 의한 산화 전후의 다양한 바이오매스의 FT-IR 스펙트럼을 나타낸 것이다.Figure 8 shows FT-IR spectra of various biomass before and after oxidation by PMA at 60°C for 8 hours.
도 8을 참조하면, PMA의 산화 후, 리그닌의 해중합으로 인해LC 바이오매스 및 리그닌의 1400-1800 cm-1에서 피크는 실질적으로 감소했다. 푸리에 변환 적외선분광법은 1400 ~ 1800 cm-1 사이의 리그닌 특성 피크가 PMA와의 반응 후에 약화되는 반면 셀룰로오스와 헤미셀룰로오스의 특성 피크는 ~1100 cm-1에서 유지됨을 보여주었다. 반면에 셀룰로오스와 헤미셀룰로오스에 해당하는 1100cm-1 부근의 피크는 무시할 수 있는 정도의 변화를 보여 60℃에서 거의 손상되지 않은 상태로 유지되었다.Referring to Figure 8, after oxidation of PMA, the peak at 1400-1800 cm -1 of LC biomass and lignin was substantially reduced due to depolymerization of lignin. Fourier transform infrared spectroscopy showed that the characteristic peak of lignin between 1400 and 1800 cm -1 was weakened after reaction with PMA, while the characteristic peak of cellulose and hemicellulose was maintained at ~1100 cm -1 . On the other hand, peaks around 1100 cm -1 corresponding to cellulose and hemicellulose showed negligible changes and remained almost undamaged at 60°C.
도 9는 LC 바이오매스 구조에 대한 PMA 처리의 효과를 나타낸 도면으로서, 60℃에서 8시간 동안 PMA와 반응하기 (a)전과 (b)후의 LC 바이오매스의 2D NMR 스펙트럼이다.Figure 9 is a diagram showing the effect of PMA treatment on the structure of LC biomass, and is a 2D NMR spectrum of LC biomass before (a) and (b) after reaction with PMA at 60°C for 8 hours.
도 9를 참조하면, 2D 13C-1H heteronuclear single-quantum correlation 핵자기공명을 이용한 리그노셀룰로오스 바이오매스 분석 결과, 반응 후 리그닌에 해당하는 피크의 현저한 강도 감소가 나타났다. 특히, 60℃에서 8시간 동안 LC 바이오매스 산화 후 G 피크의 강도는 감소한 반면 다른 피크는 변하지 않았다. G는 리그닌과 관련된다. 이 결과는 LC 바이오매스의 리그닌이 PMA의 존재 하에 선택적으로 해중합되었음을 뒷받침한다.Referring to Figure 9, the results of lignocellulose biomass analysis using 2D 13 C- 1 H heteronuclear single-quantum correlation nuclear magnetic resonance showed a significant decrease in the intensity of the peak corresponding to lignin after reaction. In particular, after LC biomass oxidation at 60°C for 8 h, the intensity of the G peak decreased, while other peaks did not change. G is related to lignin. These results support that lignin in LC biomass was selectively depolymerized in the presence of PMA.
도 10은 리그노셀룰로오스 바이오매스 및 리그닌 산화시에 생성된 바닐린 및 아세토바닐론의 양을 도시한 그래프이다.Figure 10 is a graph showing the amounts of vanillin and acetovanillone produced during oxidation of lignocellulosic biomass and lignin.
반응 후 각 바이오매스의 가용성 잔여물은 셀룰로오스와 헤미셀룰로오스의 경우 HPLC(high-performance liquid chromatography)로, 리그닌과 리그노셀룰로오스 바이오매스의 경우 GCMS(gas chromatography-mass spectrometry)로 분석했다. 1g의 리그노셀룰로오스 바이오매스는 34.1mg의 바닐린과 44.3mg의 아세토바닐론을 생산한 반면 크래프트 리그닌은 43.6mg의 바닐린을 생산했다.After reaction, the soluble residues of each biomass were analyzed by high-performance liquid chromatography (HPLC) for cellulose and hemicellulose, and gas chromatography-mass spectrometry (GCMS) for lignin and lignocellulosic biomass. One gram of lignocellulosic biomass produced 34.1 mg of vanillin and 44.3 mg of acetovanillone, while kraft lignin produced 43.6 mg of vanillin.
도 11a 내지 도 11d는 리그닌 및 LC 바이오매스의 산화로부터 생성된 방향족 화합물의 식별 및 정량화를 위한 GC-MS 분석 결과이다. 리그닌 및 LC 바이오매스로부터 가용성 방향족 화합물을 클로로포름을 사용하여 추출한 다음 60℃에서 8시간 동안 PMA와의 반응 (a, b)전과 (c, d)후에 GC-MS로 분석했다. 바닐린과 아세토바닐론은 각각 12.7분과 13.8분에 검출되었다. 8시간 동안 PMA와 반응 후 LC 바이오매스와 리그닌은 바이오매스 1g당 각각 34.1mg 및 43.6mg의 바닐린을 생성했다. 반응 전에 바닐린은 검출되지 않았다. LC바이오매스는 44.3mg의 아세토바닐론을 추가적으로 생성했다. 이러한 아세토바닐론의 추가적인 형성은 리그노셀룰로오스 바이오매스의 리그닌 분자 구조와 가혹한 화학 처리로 얻은 리그닌 간의 차이 때문일 수 있다.
Figure PCTKR2022016118-appb-img-000003
결합의 절단에서 기인한 것일 수 있다.Figures 11A to 11D are GC-MS analysis results for identification and quantification of aromatic compounds produced from oxidation of lignin and LC biomass. Soluble aromatic compounds from lignin and LC biomass were extracted using chloroform and then analyzed by GC-MS before (a, b) and after (c, d) reaction with PMA at 60°C for 8 h. Vanillin and acetovanillon were detected at 12.7 and 13.8 minutes, respectively. After reacting with PMA for 8 hours, LC biomass and lignin produced 34.1 mg and 43.6 mg of vanillin per gram of biomass, respectively. No vanillin was detected before the reaction. LC biomass produced an additional 44.3 mg of acetovanilone. This additional formation of acetovanillone may be due to differences between the molecular structure of lignin from lignocellulosic biomass and lignin obtained by harsh chemical treatment.
Figure PCTKR2022016118-appb-img-000003
It may be due to bond cleavage.
도 12는 PMA와의 반응 전후에 참나무에서 얻은 LC 바이오매스의 리그닌 함량을 나타낸 것이다. 리그닌의 함량은 클라슨법(Klason method)로 결정되었다. 자연 그대로의 오크나무(oak)는 23.7%의 리그닌을 함유하고 있었는데, 60℃ 에서 8시간 동안 PMA와 반응시킨 후 11.7%로 감소했다. 이를 통해 PMA와 산화 후 리그노셀룰로오스 바이오매스에서 original 리그닌의 50.6%가 해중합됨을 확인했다.Figure 12 shows the lignin content of LC biomass obtained from oak before and after reaction with PMA. The content of lignin was determined by the Klason method. Natural oak contained 23.7% lignin, which decreased to 11.7% after reacting with PMA at 60°C for 8 hours. Through this, it was confirmed that 50.6% of the original lignin was depolymerized in PMA and lignocellulose biomass after oxidation.
반면, 셀룰로오스 및 헤미셀룰로오스는 60℃ 에서 PMA와 반응할 때 무시할 수 있을 정도의 적은 양의 당(sugars)을 생성했다.On the other hand, cellulose and hemicellulose produced negligible amounts of sugars when reacted with PMA at 60°C.
도 13a 및 도 13b는 PMA와의 반응 후 헤미셀룰로오스와 셀룰로오스로부터 얻은 수용성 화합물의 LC 분석 결과이며, 도 13a는 헤미셀룰로오스를 8시간 동안 다른 온도에서 PMA와 반응시킨 후 얻은 부산물이며, 도 13b는 셀룰로오스를 8시간동안 다른 온도에서 PMA와 반응시킨 후 얻은 의 부산물을 나타낸다. 헤미셀룰로오스와 셀룰로오스는 C-OH, C-O-C 및 C-C 결합의 절단을 통해 90 ℃ 이상에서 실질적으로 해중합을 시작하였다.Figures 13a and 13b are LC analysis results of water-soluble compounds obtained from hemicellulose and cellulose after reaction with PMA, Figure 13a is a by-product obtained after reacting hemicellulose with PMA at different temperatures for 8 hours, and Figure 13b is a by-product obtained after reacting cellulose with PMA for 8 hours. The by-products obtained after reacting with PMA at different temperatures are shown. Hemicellulose and cellulose began to depolymerize substantially above 90°C through cleavage of C-OH, C-O-C, and C-C bonds.
도 14는 PMA와의 반응 후 LC 바이오매스, 리그닌, 헤미셀룰로오스 및 셀룰로오스에서 생성된 CO 및 CO2 기체의 GC 분석 결과 이다.Figure 14 shows the GC analysis results of CO and CO 2 gas generated from LC biomass, lignin, hemicellulose, and cellulose after reaction with PMA.
도 14를 참조하면, CO 및 CO2는 60 ℃와 90 ℃에서 8시간 동안 PMA를 사용하여 LC 바이오매스, 리그닌, 헤미셀룰로오스 및 셀룰로오스를 해중합하는 동안 생성되었다. 90 ℃ 에서 해중합으로 인해 헤미셀룰로오스와 셀룰로오스에서 CO 및 CO2의 양이 급격히 증가했다. 이러한 결과는 헤미셀룰로오스와 셀룰로오스가 60℃ 에서 해중합되지 않는다는 우리의 가설을 뒷받침했다. 결론적으로, 60℃ 에서 는 CO 및 CO2가 방출되지 않았거나 무시할 정도의 적은 양이 방출된 반면 90℃ 에서는 상당한 양이 방출되었다(보충자료 도 14).Referring to Figure 14, CO and CO 2 were produced during depolymerization of LC biomass, lignin, hemicellulose, and cellulose using PMA at 60°C and 90°C for 8 hours. At 90 °C, the amount of CO and CO2 increased rapidly in hemicellulose and cellulose due to depolymerization. These results supported our hypothesis that hemicellulose and cellulose do not depolymerize at 60°C. In conclusion, at 60°C, CO and CO2 were not released or were released in negligible amounts, whereas at 90°C, significant amounts were released (Supplementary Material Figure 14).
도 15a 및 15b는 LC 바이오매스의 미세구조에 대한 PMA 처리의 효과를 나타낸 SEM 이미지로, 도 15a 및 15b는 각각 8시간 동안 60℃ 에서 PMA와 반응하기 전과 후의 LC 바이오매스의 SEM 이미지이다. PMA와의 반응 후, LC 바이오매스에서 계층적 다공성 구조가 생성되었으며, 이는 LC 바이오매스에서 리그닌의 선택적 해중합으로 인해 셀룰로오스 성분이 거의 손상되지 않은 채로 남아 있음을 확인할 수 있다. 다시 말해, 상기 이미지는 해중합을 통한 리그닌의 선택적 제거로 인해 PMA와 반응 후 리그노셀룰로오스 바이오매스의 계층적 다공성 미세구조(hierarchical porous microstructure)가 생성됨을 보여주었다.Figures 15a and 15b are SEM images showing the effect of PMA treatment on the microstructure of LC biomass, and Figures 15a and 15b are SEM images of LC biomass before and after reaction with PMA at 60°C for 8 hours, respectively. After reaction with PMA, a hierarchical porous structure was generated in the LC biomass, which can be confirmed that the cellulose component remains almost intact due to the selective depolymerization of lignin in the LC biomass. In other words, the image showed that selective removal of lignin through depolymerization resulted in a hierarchical porous microstructure of lignocellulosic biomass after reaction with PMA.
상술한 바와 같이, 선택적 해중합을 통해 부산물이 생성되는 바, 도 16은 선택적 해중합을 통한 리그노셀룰로오스 바이오매스로부터의 전자/양성자 추출 및 부가 가치 화학 물질 생산을 나타낸 개략도이다. 도 16에 도시된 바와 같이, 리그닌은 선택적으로 해중합되어 바닐린 및 아세토바닐론과 같은 부가가치(valueadded) 화합물의 생산과 함께 전자와 양성자를 생성할 수 있다.As described above, by-products are generated through selective depolymerization, and Figure 16 is a schematic diagram showing electron/proton extraction and production of value-added chemicals from lignocellulosic biomass through selective depolymerization. As shown in Figure 16, lignin can selectively depolymerize to generate electrons and protons with the production of value-added compounds such as vanillin and acetovanillone.
탈리그닌화(delignification)는 바이오리파이너리(biofinery) 및 펄프 산업에서 가장 어렵고 에너지 집약적인 공정이라는 점을 고려할 때, 이러한 결과는 전기화학과 함께 리그노셀룰로오스 바이오매스의 활용과 관련이 있다.Considering that delignification is the most difficult and energy-intensive process in the biofinery and pulp industry, these results are relevant for the utilization of lignocellulosic biomass with electrochemistry.
리그노셀룰로오스 바이오매스에서 리그닌의 우선적 산화를 통한 전자와 양성자의 추출은 리그노셀룰로오스 바이오매스의 미세구조와 바이오매스 산화 및 PMA 환원, 두 개의 결합된 전기화학적 반쪽 반응과 관련된다. 전형적인 리그노셀룰로오스 바이오매스는 고결정성(highly crystalline) 셀룰로오스가 무정형의 헤미셀룰로오스와 리그닌으로 둘러싸여 있는 미세섬유로 구성되어 있다. 또한, 셀룰로오스 및 헤미셀룰로오스에 비해 리그닌의 더 큰 에너지 밀도(~30% 더 큼)를 고려하면 리그닌이 다른 것보다 더 큰 반응성을 가질 것으로 예상할 수 있다. 한편, 바이오매스 산화 시 전자와 양성자가 추출되는 방식은 두 개의 결합된 전기화학적 반쪽 반응으로 이해될 수 있다. 간단히 말해서, 열화학적 호기성 산화 반응(식 3)은 기질의 동시 산화(식 4)와 용존 O2의 환원 (ORR; oxygen reduction reaction) 식 5에 의해 활성화될 수 있다.The extraction of electrons and protons through preferential oxidation of lignin from lignocellulosic biomass is related to the microstructure of lignocellulosic biomass and biomass oxidation and PMA reduction, two coupled electrochemical half-reactions. Typical lignocellulosic biomass consists of microfibers of highly crystalline cellulose surrounded by amorphous hemicellulose and lignin. Additionally, considering the greater energy density of lignin (~30% greater) compared to cellulose and hemicellulose, one would expect lignin to have greater reactivity than the others. Meanwhile, the way electrons and protons are extracted during biomass oxidation can be understood as two coupled electrochemical half-reactions. Briefly, the thermochemical aerobic oxidation reaction (Equation 3) can be activated by simultaneous oxidation of the substrate (Equation 4) and reduction of dissolved O 2 (ORR; oxygen reduction reaction) Equation 5.
[식 3][Equation 3]
Figure PCTKR2022016118-appb-img-000004
Figure PCTKR2022016118-appb-img-000004
[식 4][Equation 4]
Figure PCTKR2022016118-appb-img-000005
Figure PCTKR2022016118-appb-img-000005
[식 5][Equation 5]
Figure PCTKR2022016118-appb-img-000006
Figure PCTKR2022016118-appb-img-000006
PMA가 ORR과 유사한 전위(potential) 범위에서 쉽게 가역적인 산화 환원 거동을 나타낸다는 점을 고려하면 다음 반응(식 6 내지 8)도 실현 가능하며 PMA 환원 반응(식 8))이 ORR과 경쟁할 것(식 5)이라는 것을 논리적으로 예상할 수 있다.Considering that PMA exhibits easily reversible redox behavior in a potential range similar to ORR, the following reactions (Equations 6 to 8) are also feasible and the PMA reduction reaction (Equation 8) will compete with ORR. (Equation 5) can be logically expected.
[식 6][Equation 6]
Figure PCTKR2022016118-appb-img-000007
Figure PCTKR2022016118-appb-img-000007
[식 7][Equation 7]
Figure PCTKR2022016118-appb-img-000008
Figure PCTKR2022016118-appb-img-000008
[식 8][Equation 8]
Figure PCTKR2022016118-appb-img-000009
Figure PCTKR2022016118-appb-img-000009
실제로, 반응 매질(medium)에 O2를 지속적으로 공급하면 바이오매스와 반응할 때 PMA 환원 정도가 현저히 낮아졌다.In fact, when O 2 was continuously supplied to the reaction medium, the degree of PMA reduction was significantly lowered when reacting with biomass.
도 17a 및 도17b는 각각 60℃ 에서 8시간 동안 리그닌과 LC 바이오매스와 반응할 때 PMA 환원에 대한 산소의 영향을 나타낸 것인 바, 60℃ 에서 8시간 동안 바이오매스와 반응할 때 PMA 환원에 대한 산소의 영향을 나타낸 스펙트럼이며, 지속적인 O2 퍼징(purging)은 공기 퍼지 조건과 비교하여 리그닌(70.1%에서 59.1%로) 및 LC 바이오매스(64.8%에서 45.2%로)에 의해 환원된 PMA 양의 상당한 감소로 이어졌다.Figures 17a and 17b respectively show the effect of oxygen on PMA reduction when reacting with lignin and LC biomass at 60°C for 8 hours, and show the effect of oxygen on PMA reduction when reacting with biomass at 60°C for 8 hours. This spectrum shows the effect of oxygen on oxygen, and continuous O 2 purging increases the amount of PMA reduced by lignin (from 70.1% to 59.1%) and LC biomass (from 64.8% to 45.2%) compared to air purge conditions. led to a significant decrease in
본 발명에 있어서, 리그노셀룰로오스 바이오매스의 산화로 환원된 PMA는 물을 대신하는 전자와 양성자의 효과적인 공급원으로 사용되었다.In the present invention, PMA reduced by oxidation of lignocellulosic biomass was used as an effective source of electrons and protons instead of water.
도 18 및 도 19는 각각 선형주사전위법(Linear sweep voltammetry, LSV) 및 시간대전류법(chronoamperometry, CA) 커브를 나타낸 것이다. 각 실험은 촉매 없이 탄소 나노튜브(CNT) 종이 전극을 사용하여 수행되었는 바, 도 18은 순수 0.5 M H2SO4의 LSV 곡선, 자연 그대로의 PMA3- LSV곡선, 리그노셀룰로오스 바이오매스에 의해 환원된 PMA5-의 LSV 곡선, 리그닌에 의해 환원된 PMA5-의 LSV 곡선을 나타낸 것이며, 도 19는 0.8 V vs. RHE 에서 리그노셀룰로오스 바이오매스와 리그닌에 의해 환원된 PMA5-의 CA 곡선이다. 여기서, 도 19는 리그노셀룰로오스 바이오매스와 리그닌에 의해 각각 환원된 PMA를 사용하여 0.8V vs. RHE에서 ~30 (리그닌)및 ~37mA cm-2(리그노셀룰로오스 바이오매스)의 전류 밀도를 관찰했다.Figures 18 and 19 show linear sweep voltammetry (LSV) and chronoamperometry (CA) curves, respectively. Each experiment was performed using a carbon nanotube (CNT) paper electrode without a catalyst, and Figure 18 shows the LSV curve of pure 0.5 MH 2 SO 4 , the LSV curve of pristine PMA 3- , and the reduction by lignocellulosic biomass. The LSV curve of PMA 5- and the LSV curve of PMA 5- reduced by lignin are shown, and Figure 19 shows 0.8 V vs. This is the CA curve of PMA 5- reduced by lignocellulosic biomass and lignin in RHE. Here, Figure 19 shows 0.8 V vs. 0.8 V using PMA reduced by lignocellulosic biomass and lignin, respectively. Current densities of ~30 (lignin) and ~37 mA cm -2 (lignocellulosic biomass) were observed in RHE.
도 18및 도 19를 참조하면, 종래의 전기촉매를 이용한 물 산화의 전위(즉, >1.5V vs. RHE) 보다도 훨씬 낮은 전위(<0.8 V vs. RHE)에서 O2를 생성하지 않고 환원된 PMA의 재산화를 통해 전자를 쉽게 추출할 수 있음을 확인할 수 있다.Referring to Figures 18 and 19, it was reduced without generating O 2 at a much lower potential (<0.8 V vs. RHE) than the potential of water oxidation using a conventional electrocatalyst (i.e., >1.5 V vs. RHE). It can be confirmed that electrons can be easily extracted through reoxidation of PMA.
반면 미반응(non-reacted) PMA 또는 처리되지 않은 날것의 바이오매스를 단독으로 사용할 때 전류 흐름이 관찰되지 않았는 바, 도 20은 0.8V vs. RHE에서 다양한 양극액 용액의 크로노암페로그램이다. 크로노암페로메트리를 위해 H 전지(H-cell)의 양극 구획은 60℃ 에서 8시간 동안 리그닌, 순수한 PMA(3가) 또는 리그닌에 의해 환원된 PMA(5가)로만 채워졌다.On the other hand, no current flow was observed when non-reacted PMA or raw, untreated biomass was used alone, and Figure 20 shows the 0.8V vs. Chronoamperograms of various anolyte solutions in RHE. For chronoamperometry, the anode compartment of the H-cell was filled only with lignin, pure PMA (trivalent), or PMA reduced by lignin (pentavalent) for 8 h at 60°C.
Figure PCTKR2022016118-appb-img-000010
생산을 위한 페로브스카이트 광음극 제작
Figure PCTKR2022016118-appb-img-000010
Fabrication of perovskite photocathode for production
환원된 PMA의 낮은 산화 전위는 태양 플럭스(solar flux)를 효율적으로 사용할 수 있는 낮은 밴드갭 광전극을 사용하여 H2 생산을 위한 바이어스 프리(bias-free) 광전기화학 전지를 제조하였다. 광전기화학 전지로는 가시광선에서 근적외선 스펙트럼까지의 높은 흡수성, 낮은 에너지 손실 및 내결함성 특성(defect tolerance characteristics)으로부터의 우수한 전하 수송(charge transfer stemming) 때문에 광활성 물질로 유/무기 할로겐화납 페로브스카이트(organicinorganic lead halide perovskite )를 사용하였다.The low oxidation potential of reduced PMA led to the fabrication of a bias-free photoelectrochemical cell for H 2 production using a low bandgap photoelectrode that can efficiently use solar flux. As a photoelectrochemical cell, organic/inorganic lead halide perovskites are used as photoactive materials due to their excellent charge transfer stemming, high absorption from visible to near-infrared spectrum, low energy loss, and defect tolerance characteristics. organicinorganic lead halide perovskite) was used.
도 21는 페로브스카이트 기반 광음극의 세부 구조를 도시한 것이다. 도시된 바와 같이, 광흡수층으로 1.61 eV의 밴드갭과 함께 Cs0.05(FA0.83MA0.17)0.95(PbI0.83Br0.17)3를 사용했다Figure 21 shows the detailed structure of a perovskite-based photocathode. As shown, Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 (PbI 0.83 Br 0.17 ) 3 with a band gap of 1.61 eV was used as the light absorption layer.
도 22a 내지 도 22f는 페로브스카이트 광음극를 나타낸 것이며, 도 23a 및 도23c는 Pt-Ti/FM/페로브스카이트 광음극 제조 방법을 나타낸 도면이다. 여기서,Figures 22a to 22f show a perovskite photocathode, and Figures 23a and 23c show a method of manufacturing a Pt-Ti/FM/perovskite photocathode. here,
도 22a는 페로브스카이트 광음극의 구조, 도 22b는 단면 주사 전자현미경 사진, 도 22c는 UV/Vis 흡광도 및 광발광 스펙트럼, 도 22d는 밴드 다이어그램 (band diagram), 도 22e는 전류 밀도-전압 곡선, 도 22f는 페로브스카이트 태양광 전지의 IPCE 스펙트럼이다. 도 23a는 열 증착, FM을 사용한 패시베이션, 조촉매 처리된 Pt-Ti 호일, 및 에폭시로 인캡슐레이션화를 통한 페로브스카이트 태양광 전지에 Ag 상대 전극을 증착하는 단계별 제조 과정을 도시한 것이며, 도 23b 및 도 23c는 각각 에폭시 수지로 봉지하기 전과 후의 Pt-Ti/FM/페로브스카이트 광음극 사진이다.Figure 22a shows the structure of the perovskite photocathode, Figure 22b shows a cross-sectional scanning electron microscope image, Figure 22c shows UV/Vis absorbance and photoluminescence spectrum, Figure 22d shows a band diagram, and Figure 22e shows current density-voltage. The curve, Figure 22f, is the IPCE spectrum of a perovskite solar cell. Figure 23a shows the step-by-step fabrication process for depositing Ag counter electrodes on perovskite solar cells through thermal evaporation, passivation using FM, cocatalyst treated Pt-Ti foil, and encapsulation with epoxy. , Figures 23b and 23c are photographs of the Pt-Ti/FM/perovskite photocathode before and after encapsulation with epoxy resin, respectively.
도 22a 내지 도 22f, 및 도 23a 및 도23c에 있어서, 가혹한 산성 조건에서 페로브스카이트 필름을 안정화시키기 위해 페로브스카이트 층의 벌크 및 상부 패시베이션(bulk and top passivation)을 채택하여 비복사 재결합을 줄이고 페로브스카이트 표면의 소수성을 증가시켰다. 벌크 변형(bulk modification)을 위해 페로브스카이트 전구체에 소량의 올레일아민(oleylamine) 리간드를 첨가하였다. 리간드로 덮인(ligand-capped) 결정 성장 프로세스는 결정 배향을 개선하고 커진 페로브스카이트의 소수성을 향상시켜 비방사성 재결합을 감소시키고 페로브스카이트 층의 물 침투를 차단했다. 상부 패시베이션(top passivation)을 위해 페로브스카이트 전지 표면을 낮은 농도의 PMMA 용액으로 추가 처리했다. 이 얇은 절연층은 페로브스카이트의 정공과 ETL의 전자 사이의 계면 재결합을 차단할 수 있으며 지속적인 조명 하에서 이온 이동을 억제할 수 있다. 두 기술을 모두 사용하여 개방 회로 전위는 1.17V에 도달했으며 평균값은 1.14±0.01V였다.22A to 22F and 23A and 23C, bulk and top passivation of the perovskite layer is adopted to stabilize the perovskite film in harsh acidic conditions, resulting in non-radiative recombination. and increased the hydrophobicity of the perovskite surface. For bulk modification, a small amount of oleylamine ligand was added to the perovskite precursor. The ligand-capped crystal growth process improved the crystal orientation and enhanced the hydrophobicity of the enlarged perovskite, reducing non-radiative recombination and blocking water penetration into the perovskite layer. For top passivation, the perovskite cell surface was further treated with a low concentration PMMA solution. This thin insulating layer can block interfacial recombination between holes in the perovskite and electrons in the ETL and suppress ion migration under continuous illumination. Using both techniques, the open circuit potential reached 1.17 V, with an average value of 1.14 ± 0.01 V.
또한 필즈 금속(Field's metal, FM)과 Ti 호일(0.25mm)은 산성 조건에서 각각 우수한 전기 연결과 높은 안정성을 제공하므로 사용됐다. Ti 호일은 H2 환원을 촉진하기 위해 Pt 나노 입자(20 nm)가 배치되었다.Additionally, Field's metal (FM) and Ti foil (0.25 mm) were used as they provide excellent electrical connection and high stability, respectively, in acidic conditions. The Ti foil was lined with Pt nanoparticles (20 nm) to promote H 2 reduction.
광음극에 있어서, 기포가 갇히거나 전해질이 침투하는 것을 방지하기 위해 정밀하게 가장자리의 인캡슐레이션화가 수행되었다. 광음극은 인듐 도핑된 산화주석(ITO)/PTAA:PFN-Br/Cs0.05(FA0.83MA0.17)0.95(PbI0.83Br0.17)3 perovskite/PMMAPCBM/BCP/Ag/FM/Ti-Pt 층으로 구성되었다.For the photocathode, precise edge encapsulation was performed to prevent air bubbles from being trapped or electrolyte from penetrating. The photocathode consists of indium-doped tin oxide (ITO)/PTAA:PFN-Br/Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 (PbI 0.83 Br 0.17 ) 3 perovskite/PMMAPCBM/BCP/Ag/FM/Ti-Pt layers. It has been done.
도 24는 Pt-Ti 호일의 원소 매핑 분석 결과로서, Pt 나노입자(20 nm) 증착 전후의 Ti 호일의 SEM 및 EDS 원소 매핑 분석 결과이다. EDS 매핑 이미지에서 파란색 및 녹색 점은 각각 Ti 및 Pt 원소를 나타내었다. 모든 스케일 바는 2μm 이다.Figure 24 shows the results of elemental mapping analysis of Pt-Ti foil, which shows the SEM and EDS elemental mapping analysis results of Ti foil before and after deposition of Pt nanoparticles (20 nm). Blue and green dots in the EDS mapping image represent Ti and Pt elements, respectively. All scale bars are 2μm.
도 25는 수소 발생 반응을 위해 Pt 촉매가 있거나 없는 조건에서의 페로브스카이트 광음극의 편광 곡선을 도시한 것이다. H2 생산을 위한 페로브스카이트 기반 광음극의 반쪽 전지 성능은 시뮬레이션된 태양광 조사(solar irradiation)하에 0.5M H2SO4(pH 0.65)에서 측정되었다. FM 변형 페로브스카이트(FM/perovskite), Ti 호일 변형 FM/페로브스카이트(Ti/FM/perovskite) 및 Pt 입자 증착 Ti/FM/페로브스카이트(Pt-Ti/FM/perovskite) 광전극의 성능을 비교했을 때, 태양광 H2 생성의 시작 전위(onset potentials)는 각각 0.49, 0.62, 1.14V vs. RHE였다.Figure 25 shows the polarization curve of the perovskite photocathode with and without Pt catalyst for the hydrogen evolution reaction. The half-cell performance of perovskite-based photocathode for H 2 production was measured at 0.5MH 2 SO 4 (pH 0.65) under simulated solar irradiation. FM modified perovskite (FM/perovskite), Ti foil modified FM/perovskite (Ti/FM/perovskite), and Pt particle deposited Ti/FM/perovskite (Pt-Ti/FM/perovskite) optical When comparing the performance of the electrodes, the onset potentials of solar H 2 generation were 0.49, 0.62, and 1.14 V vs. 0.49, 0.62, and 1.14 V, respectively. It was RHE.
도 26a 및 26b는 태양광 수소 생산을 위한 광음극의 반쪽 전지 성능을 나타낸 것으로서, 도 26a는 Ti 호일 부가 전후의 FM/페로브스카이트 광음극의 전류 밀도-전압 곡선을 나타낸 것이고, 도 26b는 Ti 호일이 없는 FM/페로브스카이트 광음극의 안정성을 나타낸 것이다. 도 26a에 있어서, 크로노암페로그램은 시뮬레이션된 태양광 조사 하에서 0.44V vs. RHE에서 측정되었으며, 도 26b는 Ti 호일이 없는 경우, 안정성의 급속한 저하를 보여주었다.Figures 26a and 26b show the half-cell performance of the photocathode for solar hydrogen production, with Figure 26a showing the current density-voltage curve of the FM/perovskite photocathode before and after adding Ti foil, and Figure 26b showing the current density-voltage curve of the photocathode for solar hydrogen production. This shows the stability of FM/perovskite photocathode without Ti foil. In Figure 26a, the chronoamperogram is 0.44V vs. 0.44V under simulated solar irradiation. Measured at RHE, Figure 26b showed a rapid decline in stability in the absence of Ti foil.
도 27은 태양광 수소 생산을 위한 페로브스카이트 광음극의 반쪽 전지 성능을 나타낸 것으로서 Ti 호일이 부가된 광전극을 나타낸 것이다. Ti 호일 보호가 없으면 FM/페로브스카이트 광전극은 30분 만에 성능을 빠르게 잃었지만 Pt-Ti/FM/페로브스카이트 광전극은 8시간 동안 성능을 유지했다.Figure 27 shows the half-cell performance of a perovskite photocathode for solar hydrogen production and shows a photoelectrode with Ti foil added. Without Ti foil protection, the FM/perovskite photoelectrode quickly lost its performance in 30 minutes, while the Pt-Ti/FM/perovskite photoelectrode maintained its performance for 8 hours.
바이오매스 시스템과 결합된 비보조(unassisted)
Figure PCTKR2022016118-appb-img-000011
생산 Unassisted combined with biomass systems
Figure PCTKR2022016118-appb-img-000011
production
바이어스 프리 태양광 H2 생산을 위한 바이오매스 기반 광전기화학전지는 페로브스카이트 기반 광음극과 CNT 종이 양극을 결합하여 제작되었다. 페로브스카이트 기반 광음극은 산성 매질(0.5 M H2SO4 in water)에 담그고, 양극은 전자 매개체로서 환원된 PMA를 포함하는 0.5M H2SO4에 담궜다.A biomass-based photoelectrochemical cell for bias-free solar H2 production was fabricated by combining a perovskite-based photocathode and a CNT paper anode. The perovskite-based photocathode was immersed in an acidic medium (0.5 MH 2 SO 4 in water), and the anode was immersed in 0.5 MH 2 SO 4 containing reduced PMA as an electron mediator.
도 28은 Pt-Ti/FM/페로브스카이트 광음극에 의해 생성된 태양광 H2의 분극 곡선과 양극에 의해 환원된 PMA로부터 전자 추출을 이용하여, 바이어스 프리 PEC 전지를 만들었을 때의 이론적인 최대 광전류 밀도 예상치를 나타낸 것이다.Figure 28 shows the polarization curve of solar light H 2 generated by the Pt-Ti/FM/perovskite photocathode and the theoretical diagram when a bias-free PEC cell is made using electron extraction from PMA reduced by the anode. This shows the estimated maximum photocurrent density.
도 28에 도시된 바와 같이, 20.4mA cm-2의 최대 이론적인 광전류 밀도(at 0.44V vs. RHE)는 빛 조건에서(for the H2 생산) 광음극과 어두운 조건(for PMA 재산화)에서 양극의 두 LSV 곡선의 교차점으로부터 예상되었다. 시뮬레이션된 AM 1.5G 단일 태양 조명 아래에서 19.8mA cm-2의 최대 전류 밀도(J)는 외부 바이어스(bias) 없이 거의 1패러데이 효율로 얻어졌다.As shown in Figure 28, the maximum theoretical photocurrent density of 20.4 mA cm -2 (at 0.44V vs. RHE) is obtained at the photocathode under light conditions (for the H 2 production) and under dark conditions (for PMA reoxidation). It was expected from the intersection of the two LSV curves of the anode. Under simulated AM 1.5G single solar illumination, a maximum current density (J) of 19.8 mA cm -2 was obtained with an efficiency of almost 1 Faraday without external bias.
도 29는 본 발명의 일 실시예에 따른 바이어스 프리 광전기화학 전지에서의 장기 안정성을 도시한 것이며, 도 30은 바이어스 프리, 즉, 비보조 PEC 시스템에서의 수소 생산 프로파일을 아나낸 것이며, 도 31은 비보조 태양광 수소 생산을 위한 2전극 전지를 도시한 사진이다.Figure 29 shows the long-term stability in a bias-free photoelectrochemical cell according to an embodiment of the present invention, Figure 30 shows the hydrogen production profile in a bias-free, i.e. unassisted PEC system, and Figure 31 shows This photo shows a two-electrode cell for unassisted solar hydrogen production.
도 29 내지 도 31을 참조하면, STH 효율은 24.4%로 측정되었다. 도 29에 있어서 바이어스가 없는(bias free) 광전기화학 전지는 다음 조건의 자체제작 2구획 전지에서 테스트되었는 바, 음극 구획의 페로브스카이트 광음극은 0.5M H2SO4로 채워졌고 양극 구획의 MWCNT 종이는 0.5M H2SO4에서 바이오매스에 의해 미리 환원된 0.25M PMA로 채워졌다. 나피온 멤브레인이 두 구획을 분리했다.Referring to Figures 29 to 31, STH efficiency was measured at 24.4%. In Figure 29, the bias free photoelectrochemical cell was tested in a self-made two-compartment cell with the following conditions, where the perovskite photocathode in the cathode compartment was filled with 0.5MH 2 SO 4 and the MWCNT in the anode compartment. The paper was filled with 0.25M PMA pre-reduced by biomass in 0.5MH 2 SO 4 . A Nafion membrane separated the two compartments.
도 32는 전자와 양성자의 대체 공급원로서 환원된 PMA의 역할을 보여주는 대조 실험을 나타낸 것으로, 상기한 것과 달리, 미반응 PMA3-를 사용하는 경우 광전류가 관찰되지 않았다. 이는 환원된 PMA(PMA5-)가 전자와 양성자의 대체 자원로서의 기능을 확인시켜준다. 여기서, 도 32의 2-전극 광전기화학 테스트(twoelectrode PEC test)에서 양극액으로 자연 그대로의 PMA3-를 사용할 때는 전류 흐름이 관찰되지 않은 반면 적용된 바이어스 없이 환원된 PMA5-를 사용할 때는 상당한 전류 흐름이 관찰되었다.Figure 32 shows a control experiment showing the role of reduced PMA as an alternative source of electrons and protons. Unlike the above, no photocurrent was observed when unreacted PMA 3- was used. This confirms the function of reduced PMA (PMA 5- ) as an alternative resource for electrons and protons. Here, in the two-electrode photoelectrochemical test (twoelectrode PEC test) of Figure 32, no current flow was observed when pristine PMA 3- was used as the anolyte, whereas significant current flow was observed when reduced PMA 5- was used without applied bias. This was observed.
도 33은 20시간 안정성 테스트 전후의 바이어스 없는(bias-free) PEC 시스템의 IPCE 스펙트럼을 도시한 것이며, 도 34와 표 1은 본 발명의 일 실시예에 따른 태양광 이용 수소 생산 장치와 종래 기술에 따른 태양광-화학 에너지 변환 장치의 STH 효율 비교한 그림이다.Figure 33 shows the IPCE spectrum of a bias-free PEC system before and after a 20-hour stability test, and Figure 34 and Table 1 show the solar-powered hydrogen production device according to an embodiment of the present invention and the prior art. This is a picture comparing the STH efficiency of solar-chemical energy conversion devices.
도 33을 참조하면, IPCE 스펙트럼은 광전기화학 전지가 전색(panchromatic) 태양광 H2 생산을 가능하게 함을 보여주었다. 게다가, 도 29에서 도시된 바와 같이 광전기화학 장치는 성능 저하 없이 20시간 이상 동안 단일 태양 조명에서 매우 안정적이었다. 무엇보다도 24.4% STH 효율은 단일 광전극을 사용한 태양광 H2 생산 시스템 중 광전기화학 및 광전지 보조 광전기화학/전기화학 장치와 같은 물 분해를 위한 장치 유형에 관계없이 지금까지 보고된 데이터 중 최고치에 해당하였다.Referring to Figure 33, the IPCE spectrum showed that the photoelectrochemical cell enables panchromatic solar H 2 production. Moreover, as shown in Figure 29, the photoelectrochemical device was very stable under single solar illumination for more than 20 hours without performance degradation. Above all, the 24.4% STH efficiency represents the highest data reported to date among solar H 2 production systems using a single photoelectrode, regardless of device type for water splitting, such as photoelectrochemical and photovoltaic-assisted photoelectrochemical/electrochemical devices. did.
Figure PCTKR2022016118-appb-img-000012
Figure PCTKR2022016118-appb-img-000012
Figure PCTKR2022016118-appb-img-000013
Figure PCTKR2022016118-appb-img-000013
이상에서는 본 발명의 바람직한 실시예를 참조하여 설명하였지만, 해당 기술 분야의 숙련된 당업자 또는 해당 기술 분야에 통상의 지식을 갖는 자라면, 후술될 특허청구범위에 기재된 본 발명의 사상 및 기술 영역으로부터 벗어나지 않는 범위 내에서 본 발명을 다양하게 수정 및 변경시킬 수 있음을 이해할 수 있을 것이다.Although the present invention has been described above with reference to preferred embodiments, those skilled in the art or have ordinary knowledge in the relevant technical field should not deviate from the spirit and technical scope of the present invention as set forth in the claims to be described later. It will be understood that the present invention can be modified and changed in various ways within the scope not permitted.
따라서, 본 발명의 기술적 범위는 명세서의 상세한 설명에 기재된 내용으로 한정되는 것이 아니라 특허청구범위에 의해 정하여져야만 할 것이다.Therefore, the technical scope of the present invention should not be limited to what is described in the detailed description of the specification, but should be defined by the scope of the patent claims.

Claims (26)

  1. 반투과성 멤브레인에 의해 구분된 제1 영역과 제2 영역;a first region and a second region separated by a semi-permeable membrane;
    상기 제1 영역에 제공된 제1 전극;a first electrode provided in the first area;
    상기 제1 전극에 전기적으로 연결되며 상기 제2 영역에 제공된 제2 전극;a second electrode electrically connected to the first electrode and provided in the second area;
    상기 제2 영역과 분리된 해중합부;a depolymerization section separated from the second region;
    상기 제1 영역과 상기 해중합부에 제공된 전자전달 매개체를 포함하고,Comprising an electron transfer mediator provided in the first region and the depolymerization section,
    상기 전자전달 매개체는 상기 해중합부에서 리그노셀룰로오스를 분해함과 동시에 환원되고 상기 제1 영역의 상기 제1 전극에서 산화되며,The electron transfer mediator decomposes lignocellulose in the depolymerization section and is simultaneously reduced and oxidized at the first electrode in the first region,
    상기 제2 전극에서 상기 산화로부터 발생된 전자로 양성자가 환원되는, 수소 생성 장치.A hydrogen generation device wherein protons are reduced with electrons generated from the oxidation at the second electrode.
  2. 제1 항에 있어서,According to claim 1,
    상기 리그노셀룰로오스는 셀룰로오스, 헤미셀룰로오스, 및 리그닌이 분리되지 않은 상태로 결합된 수소 생성 장치.The lignocellulose is a hydrogen generation device in which cellulose, hemicellulose, and lignin are combined without separation.
  3. 제2 항에 있어서,According to clause 2,
    상기 전자전달 매개체와 상기 셀룰로오스, 상기 헤미셀룰로오스, 및 상기 리그닌의 반응 시 상기 리그닌이 선택적으로 분해되는 수소 생성 장치.A hydrogen generation device in which the lignin is selectively decomposed upon reaction between the electron transfer mediator and the cellulose, hemicellulose, and lignin.
  4. 제3 항에 있어서,According to clause 3,
    상기 리그노셀룰로오스와 상기 전자전달 매개체의 반응 후 부산물로 바닐린, 아세토 바닐론, 구아이아콜, 시린골, 시린질 알데하이드, 메틸 시린골, 페닐 아세톤, 및 유기산 중 적어도 하나가 생성되는 수소 생성 장치.A hydrogen generation device in which at least one of vanillin, aceto vanillon, guaiacol, syringol, syringyl aldehyde, methyl syringol, phenyl acetone, and organic acid is produced as a by-product after the reaction of the lignocellulose and the electron transfer mediator.
  5. 제1 항에 있어서,According to claim 1,
    상기 제2 전극은 페로브스카이트계 광음극인 수소 생성 장치.The second electrode is a perovskite-based photocathode.
  6. 제5 항에 있어서,According to clause 5,
    상기 제2 전극은 태양 전지부를 포함하며, 상기 태양 전지부는:The second electrode includes a solar cell unit, wherein the solar cell unit:
    제1 서브전극;first sub-electrode;
    상기 제1 서브전극 상에 제공된 광반응층;a photoreactive layer provided on the first sub-electrode;
    상기 광반응층 상에 제공된 제2 서브전극을 포함하며It includes a second sub-electrode provided on the photoreactive layer,
    상기 광반응층은 페로브스카이트를 포함하는 수소 생성 장치.The photoreactive layer is a hydrogen generation device comprising perovskite.
  7. 제6 항에 있어서,According to clause 6,
    상기 제2 전극은,The second electrode is,
    상기 제1 서브전극과 상기 광흡수층 사이에 제공된 정공 수송층; 및a hole transport layer provided between the first sub-electrode and the light absorption layer; and
    상기 광흡수층과 제2 서브전극 사이에 제공된 전자 수송층 중 적어도 하나를 더 포함하는 수소 생성 장치.A hydrogen generation device further comprising at least one of an electron transport layer provided between the light absorption layer and the second sub-electrode.
  8. 제7 항에 있어서,According to clause 7,
    상기 광흡수층과 상기 전자 수송층 사이에 제공된 패시베이션층을 더 포함하는 수소 생성 장치.Hydrogen generation device further comprising a passivation layer provided between the light absorption layer and the electron transport layer.
  9. 제6 항에 있어서,According to clause 6,
    상기 태양 전지부의 외측에 제공되어 상기 태양 전지부를 보호하는 봉지부를 더 포함하며, 상기 봉지부는:It further includes an encapsulation part provided on the outside of the solar cell unit to protect the solar cell unit, wherein the encapsulation part:
    상기 제2 서브 전극 상에 제공된 제1 금속막; 및a first metal film provided on the second sub-electrode; and
    상기 제1 금속막 상에 제공된 외부 금속막을 포함하는 수소 생성 장치.A hydrogen generation device comprising an external metal film provided on the first metal film.
  10. 제9 항에 있어서,According to clause 9,
    상기 제1 금속막은 필즈 금속을 포함하며, 상기 외부 금속막은 Ti 또는 Ti-Pt를 포함하는 수소 생성 장치.The first metal film includes a fields metal, and the outer metal film includes Ti or Ti-Pt.
  11. 제10 항에 있어서,According to claim 10,
    상기 제2 전극의 적어도 일부의 외면을 감싸는 실런트를 포함하는 수소 생성 장치.A hydrogen generation device comprising a sealant surrounding at least a portion of the outer surface of the second electrode.
  12. 제1 항에 있어서,According to claim 1,
    상기 수소 생성 장치는 태양광의 유무의 따라, 상기 리그노셀룰로오스를 분해하여 상기 전자전달 매개체가 환원되고, 상기 환원된 전자전달 매개체가 산화되며 수소를 생성하는 제1 모드와, 상기 태양광을 흡수하여 수소를 생성하는 제2 모드 중 적어도 하나로 구동되는 수소 생성 장치.The hydrogen generation device has a first mode in which, depending on the presence or absence of sunlight, the lignocellulose is decomposed, the electron transfer mediator is reduced, the reduced electron transport mediator is oxidized and hydrogen is generated, and the solar light is absorbed. A hydrogen generation device driven in at least one of the second modes for generating hydrogen.
  13. 제12 항에 있어서,According to claim 12,
    상기 제1 모드는 상기 태양광이 상기 제2 전극에 제공되는 밤에 해당하고, 상기 제2 모드는 상기 태양광이 상기 제2 전극에 제공되는 낮에 해당하는 수소 생성 장치.The first mode corresponds to the night when the sunlight is provided to the second electrode, and the second mode corresponds to the day when the sunlight is provided to the second electrode.
  14. 제1 항에 있어서,According to claim 1,
    상기 수소 생성 장치는 바이어스 프리인 수소 생성 장치.The hydrogen generation device is a bias-free hydrogen generation device.
  15. 제1 항에 있어서,According to claim 1,
    상기 수소 생성 장치는 산소 발생 프리인 수소 생성 장치.The hydrogen generation device is a hydrogen generation device free of oxygen generation.
  16. 제1 항에 있어서,According to claim 1,
    상기 전자전달 매개체는 폴리옥소메탈레이트인 수소 생성 장치.The hydrogen generation device wherein the electron transfer medium is polyoxometalate.
  17. 제16 항에 있어서,According to claim 16,
    상기 전자전달 매개체는 포스포몰리브드산인 수소 생성 장치.A hydrogen generation device wherein the electron transfer medium is phosphomolybdic acid.
  18. 제1 전극에서 전자전달 매개체(mediator)를 산화시켜 산화된 전자전달 매개체를 수득하는 단계;oxidizing an electron transfer mediator at a first electrode to obtain an oxidized electron transfer mediator;
    상기 산화된 전자전달 매개체를 환원시키는 단계; 및reducing the oxidized electron transfer mediator; and
    제2 전극에서 상기 산화로부터 발생된 전자로 양성자를 환원시켜 수소를 수득하는 단계를 포함하고,Reducing a proton with an electron generated from the oxidation at a second electrode to obtain hydrogen,
    상기 전자전달 매개체를 환원시키는 단계는 리그노셀룰로오스 바이오매스를 선택적으로 분해하는 과정에서 발생된 전자를 상기 전자전달 매개체로 전달하는 단계인 수소 생성 방법.The step of reducing the electron transfer mediator is a hydrogen generation method in which electrons generated in the process of selectively decomposing lignocellulosic biomass are transferred to the electron transfer mediator.
  19. 제18 항에 있어서,According to clause 18,
    상기 리그노셀룰로오스는 셀룰로오스, 헤미셀룰로오스, 및 리그닌이 분리되지 않은 상태로 결합된 수소 생성 방법.The lignocellulose is a hydrogen production method in which cellulose, hemicellulose, and lignin are combined in a non-separated state.
  20. 제19 항에 있어서,According to clause 19,
    상기 전자전달 매개체와 상기 셀룰로오스, 상기 헤미셀룰로오스, 및 상기 리그닌의 반응 시 상기 리그닌을 선택적으로 분해하는 수소 생성 방법.A method for generating hydrogen that selectively decomposes the lignin during reaction of the electron transfer mediator with the cellulose, hemicellulose, and lignin.
  21. 제18 항에 있어서,According to clause 18,
    상기 수소 생성 장치는 태양광의 유무의 따라, 상기 리그노셀룰로오스를 분해하여 상기 전자전달 매개체가 환원되고, 상기 환원된 전자전달 매개체가 산화되며 수소를 생성하는 제1 모드와,The hydrogen generation device has a first mode in which, depending on the presence or absence of sunlight, the lignocellulose is decomposed, the electron transfer mediator is reduced, and the reduced electron transfer mediator is oxidized to generate hydrogen;
    상기 태양광을 흡수하여 수소를 생성하는 제2 모드 중 적어도 하나로 구동되는 수소 생성 방법.A hydrogen generation method driven in at least one of the second modes for generating hydrogen by absorbing sunlight.
  22. 제21 항에 있어서,According to claim 21,
    상기 제1 모드는 상기 태양광이 상기 제2 전극에 제공되는 밤에 해당하고, 상기 제2 모드는 상기 태양광이 상기 제2 전극에 제공되는 낮에 해당하는 수소 생성 장치.The first mode corresponds to the night when the sunlight is provided to the second electrode, and the second mode corresponds to the day when the sunlight is provided to the second electrode.
  23. 제1 서브 전극;first sub-electrode;
    제1 서브 전극 상에 제공된 광반응층;A photoreactive layer provided on the first sub-electrode;
    상기 광반응층 상에 제공된 패시베이션층;A passivation layer provided on the photoreactive layer;
    상기 패시베이션층 상에 제공된 전자수송층; 및An electron transport layer provided on the passivation layer; and
    상기 전자수송층 상에 제공된 제2 서브 전극을 포함하며,It includes a second sub-electrode provided on the electron transport layer,
    상기 광반응층은 페로브스카이트를 포함하는 태양 전지.A solar cell in which the photoreactive layer includes perovskite.
  24. 청구항 23항의 태양 전지; 및The solar cell of claim 23; and
    상기 태양 전지의 외측에 제공되어 상기 태양 전지를 보호하는 봉지부를 포함하며, 상기 봉지부는:It includes an encapsulation part provided on the outside of the solar cell to protect the solar cell, wherein the encapsulation part:
    상기 제2 서브 전극 상에 제공된 제1 금속막; 및a first metal film provided on the second sub-electrode; and
    상기 제1 금속막 상에 제공된 외부 금속막을 포함하는 광음극.A photocathode including an external metal film provided on the first metal film.
  25. 제24 항에 있어서,According to clause 24,
    상기 제1 금속막은 필즈 금속을 포함하며, 상기 외부 금속막은 Ti 또는 Ti-Pt를 포함하는 광음극.The first metal film includes a fields metal, and the outer metal film includes Ti or Ti-Pt.
  26. 제24 항에 있어서,According to clause 24,
    상기 태양 전지 및 봉지부의 적어도 일부의 외면을 감싸는 실런트를 포함하는 광음극.A photocathode comprising a sealant surrounding at least a portion of the outer surface of the solar cell and the encapsulation part.
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