KR20210092503A - Photoelectrochemical(PEC) device Comprising CIGS Photovoltaic-Photoelectrode Tandem Configuration - Google Patents

Abstract

The present invention relates to a photoelectrochemical (PEC) device comprising a photoanode, a photocell, and a cathode and, more specifically, to a PEC device comprising a photoanode, a Cu(In,Ga)Se_2 (CIGS) photocell, and a cathode, and a cofactor regeneration method, an artificial photosynthesis method, and a hydrogen production method using the PEC device. Powerful photocell cells are essential for long-term redox biotransformation in biocatalytic PEC platforms. In accordance with the present invention, a photoanode/CIGS/cathode tandem assembly comprising a single CIGS photocell for a bias-free photo-biocatalytic reduction reaction can induce a cofactor-dependent biocatalytic reaction under visible light with high efficiency for a long time so that the PEC device is useful as a powerful PEC-PV device for realizing long-term artificial photosynthesis.

Description

Photoelectrochemical (PEC) device Comprising CIGS Photovoltaic-Photoelectrode Tandem Configuration

The present invention relates to a photoelectrochemical (PEC) device comprising a photoanode, a photovoltaic and a cathode, and more particularly, a photoanode, CIGS (Cu(In,Ga)Se ₂ ) photovoltaic cell and a photoelectrochemical (PEC) device including a cathode, a cofactor regeneration method using the device, an artificial photosynthesis method, and a hydrogen production method.

Solar-powered biocatalysis in a photoelectrochemical (PEC) platform promotes a sustainable solar-chemical conversion using water as an electron donor. Mechanically, for the production of value-added chemicals, photoelectrodes require light and electricity to transfer photoexcited charge carriers to a redox biocatalytic reaction. Most prior biocatalytic PEC studies required a high external bias of 1.2 V to promote NADH-dependent enzymatic reactions (SK et al. , Angew. Chem. Int. Ed. 2017, 56 , 3827-3832).

To use solar energy as the sole energy source (ie no external bias), organic-inorganic halogen perovskite solar cells in PEC-photovoltaic (PEC-PV) tandem devices were used. cell; PSC) to simultaneously drive NADH-dependent biocatalytic reaction and H ₂ O oxidation (YW Lee, et al. , Nat. Commun. 2018, 9 , 4208). However, deterioration of PSCs is caused by the complex interaction of many factors, such as moisture, light, O ₂ , and electrical bias, and the low stability of these PSC platforms is a major obstacle (R. Wang, et al. , Adv. Funct. Mater. 2019, 0 , 1808843). For example, water molecules dissolve organic cations in organometallic perovskite and alter the structure of PSCs. Irradiation of UV or blue light itself leads to the decomposition of PSCs by the photocatalytic effect of _{mesoporous TiO 2 .} Even in the _{presence of O 2 , photoexcited PSCs generate O 2} ⁻ radicals to destroy organic components of PSCs.

Therefore, the present inventors have found that copper indium gallium selenium [Cu(In,Ga)Se ₂ ; CIGS] (Q. Cao, et al. , Adv. Energy Mater. 2011, 1 , 845-853) thought that inorganic photovoltaic cells would be more suitable for biocatalytic PEC systems. In particular, CIGS solar cells have been commercialized in thin-film PV technology due to their photophysical advantages such as direct bandgap (1.12 eV), high absorption coefficient (10 ⁵ cm ^{-1 ), high radiation resistance, and excellent operating durability.} Leading the way (J. Ramanujam, UP Singh, Energ. Environ. Sci. 2017, 10 , 1306-1319).

Accordingly, the inventors of the present inventors made diligent efforts to develop a PEC device that induces a biocatalytic reaction using solar energy as a sole energy source. As a result, a PEC device in which a photoanode/CIGS photocell/cathode has a tandem structure was developed. It was confirmed that the transmitted light provided a photovoltage high enough to activate the CIGS photocell and drive the bias-free coupling of water oxidation and regeneration of cofactors such as NADH, thereby completing the present invention.

The information described in the background section is only for improving the understanding of the background of the present invention, and it does not include information forming prior art known to those of ordinary skill in the art to which the present invention pertains. may not be

An object of the present invention is to provide a photoelectrochemical device that induces a biocatalytic reaction using solar energy as a sole energy source.

Another object of the present invention is to provide a cofactor regeneration method, artificial photosynthesis method, and hydrogen production method using the photoelectrochemical device.

In order to achieve the above object, the present invention provides _{a photoelectrochemical (PEC) device including a photoanode, CIGS (Cu(In,Ga)Se 2} ) photovoltaic and a cathode (cathode).

The present invention also comprises the steps of adding a solution containing an oxidation-type cofactor, an electron transport mediator and an electron donor to the photoelectrochemical (PEC) device; and irradiating a light source to regenerate the oxidized cofactor into a reduced cofactor.

The present invention also comprises the steps of adding a solution containing an oxidation-type cofactor, an electron transfer mediator and an electron donor to the photoelectrochemical (PEC) device, and then irradiating a light source to regenerate the cofactor; and using the regenerated cofactor in a redox reaction of a substrate of an oxidoreductase to prepare a useful material.

The present invention also provides a hydrogen production method comprising adding an electrolyte solution to the photoelectrochemical (PEC) device and then irradiating a light source.

A powerful photovoltaic cell is essential for long-term redox biotransformations in a biocatalytic photoelectrochemical platform, and a photoanode/CIGS/cathode tandem assembly comprising a single CIGS photocell for a bias-free photo-biocatalytic reduction reaction according to the present invention It is useful as a powerful PEC-PV device for realizing long-term artificial photosynthesis because it can induce a cofactor-dependent biocatalytic reaction with high efficiency for a long time under visible light.

1 shows a tandem structure based on a single Cu(In,Ga)Se ₂ solar cell and a water-oxidation photoanode developed for photo-biocatalytic CO ₂ reduction without bias. The hybrid energy conversion platform is based on solar energy. Provides sufficient photovoltage for formate dehydrogenase-induced _{conversion of CO 2 to formate.}
2 shows a schematic diagram of a CIGS-based PEC-PV tandem apparatus for bias-free biocatalytic CO _{2 -formate conversion.} The fully tandem device consists of a FeOOH/BiVO ₄ photoelectrode (for H ₂ O oxidation), a single CIGS photocell (to supply additional bias to the photoelectrode), and a meso ITO electrode (for NADH regeneration). This tandem cell provides a photovoltage large enough to gain electrons from _{H 2} O oxidation, transfer electrons to meso- ITO, and reduce organometallic electron mediators (M ) for site-specific regeneration of NADH from ^NAD+. . At the active site of Ts FDH, NADH returns to its oxidized form after transferring the hydride from the nicotinamide moiety to the CO _{2 molecule.} SLG stands for soda-lime glass, i-ZnO stands for intrinsic ZnO, FTO stands for fluorine-doped tin oxide, and ITO stands for indium tin oxide.
3A is FeOOH / BiVO _4-under including a filtered light or one trillion people that do not include / J of the CIGS and perovskite solar cell - will showing a V curve, Figure 3B is irradiated (xenon lamp, λ> 400nm, P: 100mW cm - ² ) shows the J - V profiles of BiVO ₄ and FeOOH/BiVO _{4 under 2).} Figure 3C shows the J - V curves of FeOOH/BiVO ₄ , FeOOH/BiVO ₄ /CIGS and FeOOH/BiVO ₄ /Perovskite under illumination (xenon lamp, λ>400nm, P : 100mW cm ^-2 ), the counter electrode is It is stainless steel. 3D shows the bias-free CPPE of two different tandem devices in a two-electrode configuration. 3B, C and D, _{the geometric surface areas of FeOOH/BiVO 4} , CIGS and perovskite are 0.45, 0.45 and 4 cm ² , respectively, the electrolyte solution is sodium phosphate buffer (100 mM, pH 7.0), and the scan rate is 50 mV s ^-1 .
4 is box-and-whisker plots of photovoltaic parameters (eg, J sc, V oc, FF and PCE) for 20 CIGS solar cells.
Figure 5 shows the external quantum efficiency and integrated photocurrent density of a CIGS photovoltaic cell, with applied bias being 0V.
_{6 shows the effect of BiOI deposition time on the photocurrent of BiVO 4} for _{500 mM Na 2} SO ₃ oxidation under front illumination, and the photocurrent was optimized by changing the thickness of the BiOI film. As the deposition time of BiOI increased, the photocurrent of _{BiVO 4 increased, and the thickness of BiVO 4} decreased (see FIGS. 7A and 7B). However, _{the nanostructure morphology and crystallinity of BiVO 4} did not change (see FIGS. 7C, 7D, and 8). These results imply that _{the thin thickness of the BiVO 4} photoanode is advantageous for increasing the photoanode current (under front illumination) because of the short migration path of photoexcited electrons from _{BiVO 4 to FTO.}
7 is a plan view and cross-sectional scanning electron microscope (SEM) image of the BiVO ₄ electrode. In FIGS. 7A and 7C, the deposition time of BiOI is 1 minute, and in FIGS. 7B and 7D, the deposition time of BiOI is 3 minutes. The scale bars in FIGS. 7A, B, C and D are 2000, 2000, 800 and 800 nm, respectively.
_{8 shows the X-ray diffraction (XRD) pattern of BiVO 4} with deposition times of 1 minute and 3 minutes, and the standard diffraction pattern of JCPDS #01-083-1699 is presented for comparison, and an asterisk (*) denotes the XRD peak of FTO.
Figure 9 shows the I - V profile overlap of FeOOH/BiVO ₄ , CIGS photocells and PSCs, where the y-values at the intersections are _{the estimated photocurrents of the tandem devices (i.e., FeOOH/BiVO 4} /CIGS and FeOOH/BiVO ₄ /Perovskite). indicates. The geometric surface areas of FeOOH/BiVO ₄ , CIGS and perovskite are 4, 0.45 and 0.45 cm ^{2 ,} respectively.
Figure 10A shows the electrochemical formation of NADH by meso- ITO cathode, M is Cp*Rh(bpy)H ₂ O ²⁺ . 10B is a scanning electron microscope image of a meso ITO electrode (top view, scale bar: 100 nm). Figure 10C shows the dependence of cyclic voltammograms of meso- ITO and ITO electrodes on the scan rate. 10D shows the change of linear sweep voltammograms of the meso- ITO negative electrode according to the sequential addition of redox biocatalyst components (ie, M and NAD ^{+ ) at pH 7.0, and the scan rate is 20 mV s -1} . Figure 10E is a shows an initial velocity comparison result of the electrochemical formation of NADH which is driven by a meso ITO and ITO cathode does not contain include M or / and the reaction conditions were 250μM M and 1mM NAD ^+, meso ITO, and the ITO electrode The geometric surface area is 1 cm ² , the electrolyte solution is sodium phosphate buffer (100 mM, pH 7.0), the counter electrode is stainless steel, and ND means not detected.
11 is a cross-sectional SEM image of meso ITO, and the scale bar is 10 μm.
12 shows the XRD pattern of meso- ITO, below is the corresponding XRD peak of the ITO standard card (JCPDS #01-083-3350).
13 shows linear sweep voltammograms of a meso ITO electrode (geometric surface area: 1 cm ^-2 ) in the presence and absence of ^{NAD +} , the scan rate is 20 mV s ^-1 , the counter electrode is stainless steel, and the solvent is sodium phosphate buffer (100 mM , pH 7.0).
14 shows a chronoamperogram of meso- ITO and planar ITO electrodes for M reduction, with a geometric surface area of 1 cm ² , and an applied bias of -0.28V vs. It is RHE. The unit of the y-axis is ampere, the counter electrode is stainless steel, and the reaction conditions are 250 μM M in a sodium phosphate buffer (100 mM, pH 7.0) with stirring.
15 is a view of FeOOH/BiVO ₄ /CIGS device and meso- ITO electrode _{for H 2 O oxidation and NADH regeneration, respectively.} I |- showing the overlap of the V plots, the | of the meso ITO. I |- V curves were obtained as follows: (i) | of meso ITO without M and NAD ⁺ I |- V curves and (ii) of meso ITO with 0.5 mM M and 1 mM NAD ^{+ under stirring |} I |- V curves were obtained. Then, the curve of the former is subtracted from the curve of the latter to obtain the Faraday current by the M reduction reaction in the presence of ^{NAD + .} The geometric surface areas of FeOOH/BiVO ₄ , CIGS and meso- ITO are 4, 0.45 and 1 cm ² , respectively, and the light source is a xenon lamp (λ>400 nm, P : 100 mW cm ^-2 ).
_{16A is a series of control experimental results for bias-free photoelectrochemical production of NADH by FeOOH/BiVO 4} /CIGS/ meso ITO during 3 h reaction, and FIG. 16B is CIGS- and perovskite-based full tandem apparatus under different RH. The comparative results of NADH formation driven by 16C shows a possible mechanism of NADH regeneration without bias by a CIGS-based full tandem cell, where OC is an ohmic contact, CB is a conduction band, VB is a valence band, E _F,n is a quasi-Fermi level of electrons, E _F,h means quasi-Fermi level of holes. FIG. 16D shows the _{biocatalytic production of formate using FeOOH/BiVO 4} /CIGS/ meso ITO, and FIG. 16E shows enzymatic formate driven by CIGS- and perovskite-based full tandem cells for 72 h reaction under different RH. As a result of comparison of production, ND means not detected.
17 shows the effect ^{of the NAD +} concentration on the NADH regeneration rate at the time of 1 hour reaction and the NADH concentration at the reaction time of 3 hours. Reaction condition: 0.5mM M and NAD ⁺ dissolved in a sodium phosphate buffer (100mM, pH 7.0). Working electrode: FeOOH/BiVO ₄ /CIGS. Counter electrode: meso ITO. Applied bias: 0V. Light source: xenon lamp ( P : 100mW cm ^-2 , λ>400nm).
18 is a control experiment for _{photo-biocatalytic CO 2} -formate conversion without bias in the absence of light, CIGS, FeOOH or BiVO ₄ (A) and in the absence of M , NAD ⁺ , CO ₂ or Ts FDH (B). It is the result. Experimental group reaction conditions: 0.5mM M and 0.5mM NAD ₊ in a sodium phosphate buffer (100mM, pH 7.0). Working electrode: FeOOH/BiVO ₄ /CIGS. Counter electrode: meso ITO. Light source: xenon lamp ( P : 100mW cm ^-2 , λ>400nm). Applied bias: 0V. Reaction time: 4 h. ND: not detected.
19 shows the dependence of formate production rate on Ts FDH concentration (A) and NAD ^{+ concentration (B).} 19A reaction conditions: 0.5 mM M, 0.5 mM NAD ⁺ , and Ts FDH in a sodium phosphate buffer (100 mM, pH 7.0). 19B reaction conditions: 0.5 mM M, NAD ⁺ , and 10U ml ^-1 Ts FDH in a sodium phosphate buffer (100 mM, pH 7.0). _{Gas CO 2} (99.999%) was continuously removed before or during the experiment. Working electrode: FeOOH/BiVO ₄ /CIGS. Counter electrode: meso ITO. Applied bias: 0V. Light source: xenon lamp(λ>400 nm, P : 100mW cm ^-2 ).
Figure 20A shows the bias-controlled potential photoelectrolysis (CPPE) of a CIGS-based fully tandem device in the first and second cycles, and Figure 20B shows the form in a 12 h biocatalytic photoelectrochemical reaction of the first and second cycles. It indicates the acid concentration. After the first cycle (72 h), the reaction solution was changed and a second CPPE was performed ( FIG. 16D shows the overall I - t curve of the first cycle). Reaction condition: 0.5mM M, 0.5mM NAD ⁺ , and 10U ml ^-1 Ts FDH in a sodium phosphate buffer (100mM, pH 7.0). Working electrode: FeOOH/BiVO ₄ /CIGS. Counter electrode: meso ITO. Light source: xenon lamp(λ>400nm, P : 100mW cm ^-2 ).

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In general, the nomenclature used herein is those well known and commonly used in the art.

In the present invention, a first example of using a single CIGS photocell in a photoelectrochemical (PEC)-photovoltaic (PV) tandem device and a bias-free biocatalytic CO ₂ reduction using water as an electron donor of the device presents the application of

As shown in FIG. 2 , the tandem absorber is composed of an FeOOH/BiVO ₄ upper cell (photoelectrode) and a single CIGS lower cell (PV), and is connected to an anode, a mesoporous indium tin oxide ( meso ITO) electrode. do. Among n-type semiconductors _{, the BiVO 4} photoelectrode, a material that exhibits the best performance in _{H 2} O oxidation, functions as an electron extractor from _{H 2} O for electron transfer to the meso-ITO cathode. Light transmitted through the photoanode activates the CIGS solar cell, which provides a photovoltage high enough to drive the bias-free coupling of NADH regeneration and water oxidation. The PEC-PV tandem system according to the present invention can be used with previously reported double or multi-junction PVs (e.g., double-junction Si solar cells (FF Abdi, et al. , Nat. Commun. 2013, 4 , 2195) and triple It is much simpler and more economical than systems using bonded Si PVs (SY Reece, et al. , Science 2011, 334, 645-648).

The electrocatalytic meso- ITO electrode uses electrons to reduce the Rh-based electron transport mediator [Cp ^* Rh(bpy)H ₂ O ²⁺ , M ] for ^{the site-specific regeneration of 1,4-NADH from NAD + .} Then, Thiobacillus sp. KNK65MA-derived formate dehydrogenase ( Ts _{FDH) converts CO 2} into formate by receiving hydride ions from 1,4-NADH. The Ts FDH biocatalyst driven by the tandem device according to the present invention lasted more than 72 hours and produced 5.6 mM formate. These are the highest recorded reaction times and concentrations, respectively, among mediated electron transfer-type biocatalysts using the PEC platform.

In the present invention, in order to reproduce NADH based on a photoelectrochemical cell (PEC cell) capable of converting solar energy and water into useful chemicals by mimicking natural photosynthesis, a CIGS-based fully tandem photoelectrochemical device (i.e., FeOOH/BiVO ₄ /CIGS/ meso ITO) was prepared.

Accordingly, the present invention, in one aspect, relates to a photoelectrochemical (PEC) device comprising a photoanode, a CIGS (Cu(In,Ga)Se _{2 ) photovoltaic and a cathode.}

As used herein, the term "photoelectrochemical (PEC) device" means an electrochemical device that converts light energy into electrochemical energy, and "Photoelectrochemical (PEC)-photovoltaic (PV) tandem ( "tandem) device" means a photoelectrochemical device comprising a photocell, comprising: a photoanode; It refers to a device in which a photovoltaic cell and a negative electrode form a tandem structure.

In the present invention, the photoanode, the CIGS photocell, and the cathode may be characterized in that they form a tandem structure.

In the present invention, the term “tandem structure” refers to a structure in which two or more light absorbers complementary to each other are stacked in series. There are advantages in that all of the sunlight can be used and that since two or more light absorbers are connected in series, the photo voltage increases and high efficiency can be obtained.

In the present invention, the photoanode is any one selected from the group consisting _{of FeOOH/BiVO 4} , NiOOH/BiVO ₄ , NiOOH/FeOOH/BiVO ₄ , α-Fe ₂ O ₃ and WO _{3 It may be characterized in that it is} , but is not limited thereto. Preferably, it may be characterized as FeOOH/BiVO _{4 .}

As used herein, the term “photovoltaic” is used in the same sense as “solar cell” and refers to a device capable of converting solar energy into electrical energy.

In the present invention, "CIGS (Cu(In,Ga)Se ₂ ) photovoltaic cell" is a compound of copper (Copper; Cu), indium (In), gallium (Ga), selenium (Selenide; Se) A photovoltaic cell used as a light absorption layer.

In the present invention, the negative electrode is ITO (indium tin oxide), FTO (fluorine-doped tin oxide), stainless steel (stainless steel), TiO ₂ , Pt, glassy carbon electrode (glassy carbon electrode), carbon cloth (carbon cloth) ), carbon felt (carbon felt) and carbon nanotube buckypaper (carbon nanotube buckypaper) may be characterized in that any one or more selected from the group consisting of, but is not limited thereto.

In the present invention, the ITO may be characterized in that porous indium tin oxide (mesoporous indium tin oxide; meso ITO). Therefore, preferably, the negative electrode may be characterized as meso ITO, but is not limited thereto.

In the present invention, the photoelectrochemical device may be a device for cofactor regeneration or hydrogen production.

Powerful photovoltaic cells are essential for long-term redox biotransformation in biocatalytic photoelectrochemical platforms. In one embodiment of the present invention, the photoanode/CIGS/cathode tandem assembly _{induces a cofactor-dependent biocatalytic CO 2} reduction under visible light, with a long reaction time of 72 hours and a maximum conversion frequency of cofactors (0.236). h ⁻¹ ) and a total number of conversions (11.2). The excellent photoelectrochemical stability of the CIGS component contributes to this performance. It was confirmed that when CIGS was replaced with a perovskite solar cell (PSC), unstable photocurrent and low concentration of formate were generated in a humid environment due to moisture-induced decomposition of PSC.

In an embodiment of the present invention, a water decomposition reaction (oxygen gas and hydrogen gas generation) was induced under visible light using a photoanode/CIGS/cathode tandem assembly, and this was confirmed through a current density-time graph. This means that hydrogen can be effectively produced using the PEC device according to the present invention.

In the present invention, a single CIGS photovoltaic cell in a PEC-PV tandem configuration for bias-free photo-biocatalytic CO _{2 reduction is presented.} We combined a CIGS photovoltaic cell with a water-oxidized FeOOH/BiVO ₄ photoanode and meso ITO cathode that induces NADH regeneration and _{enzymatic conversion of CO 2 to formate.} The synergistic effect of photovoltages generated by both CIGS and FeOOH/BiVO ₄ enabled meso- ITO electrodes to achieve a photo-excited electron transfer cascade to Ts ^{FDH via Rh-based electron mediators and NAD + cofactors.} A CIGS-based fully tandem device (i.e., FeOOH/BiVO ₄ /CIGS/ meso- ITO) was tested for the baseline performance of a biocatalytic PEC system with cofactor regeneration (formate concentration: 5.6 mM, TOF _NAD+ : 0.236h ^-1 , TTN _NAD+). : 11.2) was achieved. The excellent photoelectrochemical stability of CIGS photovoltaic cells served as a new reference point. The photovoltaic cells in which CIGS was replaced with perovskite showed lower enzymatic productivity under 40, 60 and 80% RH due to water-induced degradation of PSCs. Consequently, in the present invention, CIGS photovoltaic cells have been established as a suitable energy material for realizing long-term artificial photosynthesis.

In this specification, the terms 'unbiased' or 'bias-free' are used in the same sense and refer to using solar energy as a sole energy source.

Accordingly, the present invention, in another aspect, (a) adding a solution containing an oxidation-type cofactor, an electron transport mediator and an electron donor to the photoelectrochemical (PEC) device; and (b) irradiating a light source to the photoelectrochemical (PEC) device to regenerate the oxidized cofactor into a reduced cofactor.

In the present invention, the electron donor is water (H ₂ O), triethanolamine (TEOA, triethanolamine), ethylenediaminetetraacetic acid (EDTA, Ethylenediaminetetraacetic acid), citric acid (Citric acid), ascorbic acid (Ascorbic acid) and oxalic acid (Oxalic acid) may be characterized as selected from the group consisting of, but is not limited thereto, and may preferably be characterized as water.

When an organic compound such as triethanolamine or ethylenediaminetetraacetic acid is used as an electron donor, organic compounds remain in the by-product, but when water is used as an electron donor, there is an environmentally friendly advantage.

"Cofactor" means a factor that helps the action of a protein or the like in an organism.

In the present invention, the oxidized cofactor to be photochemically reduced is a nicotinamide cofactor NAD ⁺ (nicotinamide adenine dinucleotide), NADP ⁺ (nicotinamide adenine dinucleotide phosphate), a flavin cofactor FAD ⁺ (flavin adenine dinucleotide) and It may be characterized in that it is selected from the group consisting of FMN ^{+ (flavin monoucleotide), but is not limited thereto.}

In the present invention, The reduction cofactor to be reproduced by irradiating the light source to the opto-electronic device, chemical NADH, NADPH, FADH and FMNH _2, but can be characterized as being selected from the group consisting of _2, without being limited thereto.

In the present invention, the electron transport mediator may be selected from the group consisting of methylviologen, ruthenium (II) complex, and rhodium (III) complex, but is not limited thereto.

In the present invention, the electron transport mediator is used as a primary mediator for transferring the photoinduced electrons to the oxidation-type cofactor. In general, direct electron transfer, in which electrons are transferred directly to a cofactor without passing through an electron mediator, results in the formation of isomers and dimers of the cofactor. It does not have enzyme activity, so the final product cannot be obtained in the oxidoreductase reaction.

In the present invention, the rhodium(III) complex is preferably (pentamethylcyclopentadienyl-2,2'-bipyridinechloro)rhodium(III):[Cp ^* Rh(bpy)H ₂ O] ²⁺ It can be characterized as In the present specification, the [Cp ^* Rh(bpy)H ₂ O ²⁺ ] is represented by M , Cp* is C ₅ Me ₅ , and bpy means 2,2'-bipyridine.

A rhodium-based organometallic compound having high regio-selectivity is used as a major medium for producing enzymatically active NADH.

In another aspect, the present invention provides a method comprising: (a) adding a solution containing an oxidation-type cofactor, an electron transport mediator and an electron donor to the photoelectrochemical (PEC) device, and then irradiating a light source to regenerate the cofactor; and (b) using the regenerated cofactor in a redox reaction of a substrate of an oxidoreductase to prepare a useful substance.

The artificial photosynthesis of the present invention mimics the light reaction of natural photosynthesis to regenerate cofactors using a photoelectrochemical (PEC) device including a photoanode, CIGS photocell, and anode, and mimics the dark reaction to mimic the dark reaction and enzymatic reaction using all oxidoreductases. It refers to the process of manufacturing useful substances.

In the present invention, useful substances produced by artificial photosynthesis are formic acid, glutamate, aspartate, lactate, unnatural amino acid, ibuprofen, pravastatin New drug raw materials including (Pravastatin) and Texol, high value-added fine chemicals such as optical isomers, as well as chemical fuels such as methanol, functional seasonings, etc. can be exemplified, but produced by oxidoreductase reaction includes all substances.

In the present invention, the electron donor is water (H ₂ O), triethanolamine (TEOA, triethanolamine), ethylenediaminetetraacetic acid (EDTA, Ethylenediaminetetraacetic acid), citric acid (Citric acid), ascorbic acid (Ascorbic acid) and oxalic acid (Oxalic acid) may be characterized as selected from the group consisting of, but is not limited thereto, and may preferably be characterized as water.

In the present invention, the oxidation-type cofactor is selected from the group consisting of ^{NAD +} (nicotinamide adenine dinucleotide), NADP ⁺ (nicotinamide adenine dinucleotide phosphate), FAD ⁺ (flavin adenine dinucleotide) and FMN ^{+ (flavin monoucleotide).} can, but is not limited thereto.

In the present invention, the electron transport mediator may be selected from the group consisting of methylviologen, ruthenium (II) complex, and rhodium (III) complex, but is not limited thereto.

In the present invention, the rhodium(III) complex is (pentamethylcyclopentadienyl-2,2'-bipyridinechloro)rhodium(III):[Cp ^* Rh(bpy)H ₂ O] ²⁺ can be done with

In the present invention, the oxidoreductase is FDH (formate dehydrogenase), GDH (glutamate dehydrogenase), ADH (Alcohol dehydrogenase), G6PDH (glucose-6-phosphate dehydrogenase), LDH (lactic dehydrogenase), MDH (malate dehydrogenase) and It may be characterized in that it is selected from the group consisting of succinic dehydrogenase (SDH), but is not limited thereto.

In one embodiment of the present invention, FDH used for the biocatalytic reaction of formic acid is an oxidoreductase that simultaneously activates formate oxidation and carbon dioxide reduction. There are several types of NADH-dependent FDH, such as CsFDH, AaFDH, PsFDH, and TsFDH, including commercially available CbFDH, depending on the expression species. In general, FDH has the preference for the formate oxidation reaction, but the preference for the carbon dioxide reduction reaction. Because of the larger size, it was difficult to realize the carbon dioxide immobilization reaction by FDH. However, according to a recent study, Thiobacillus sp. It has been reported that derived FDH (TsFDH) has superior catalytic activity for carbon dioxide reduction reaction compared to other FDHs (H, Choe et al., PlosONE, 9:e103111, 2014). Therefore, in an embodiment of the present invention, CO ₂ immobilization reaction was performed using TsFDH as a biocatalyst.

In the present invention, the regenerated cofactor may be oxidized after the redox reaction in step (b) and re-added in step (a).

In another aspect, the present invention relates to a hydrogen production method comprising adding an electrolyte solution to the photoelectrochemical (PEC) device and then irradiating a light source.

In the present invention, the electrolyte solution includes water (H ₂ O) and an ionizing compound, and the ionizing compound is lithium chloride, potassium chloride, sodium chloride, calcium chloride, potassium nitrate, sodium nitrate, potassium sulfate, sodium sulfate, and mixtures thereof. It may be characterized in that it is selected from the group consisting of, but is not limited thereto.

As used herein, the term “electrolyte solution” refers to a solution in which an electrolyte, which is a material that ionizes when dissolved in a solvent such as water, is dissolved.

In an embodiment of the present invention, as a _{result of adding an electrolyte solution to FeOOH/BiVO 4} /CIGS and stainless steel and then irradiating a light source, protons are reduced to _{generate hydrogen gas (H 2} ) (FIG. 3D).

Hereinafter, the present invention will be described in more detail through examples. These examples are only for illustrating the present invention, and it will be apparent to those of ordinary skill in the art that the scope of the present invention is not to be construed as being limited by these examples.

Example 1: Materials and Methods

Example 1-1: Chemicals

Potassium hydride, ethanol, bismuth(III) nitrate pentahydrate, potassium iodide, ethanol, nitric acid, p -benzoquinone, vanadyl acetylacetonate, dimethyl sulfoxide (DMSO), indium tin oxide nanopowder, acetic acid, β-NAD ⁺ hydrate (NAD ⁺ ) and sodium formate were purchased from Sigma-Aldrich (St. Louis, MO, USA). These chemicals were used without further purification. To prepare a buffer solution, type 1 ultrapure water (18 MΩ cm) of Direct-Q® 5 UV ultrapure water purification system (Millipore Corp., USA) was used. Organometallic mediators and Ts FDH were produced according to literature (YW Lee, et al. , Nat. Commun. 2018, 9 , 4208; H. Choe, et al., PLoS One 2014, 9 , e103111).

Example 1-2: Photovoltaic Cell Fabrication

CIGS photovoltaic cells in Mo/CIGS/CdS/i-ZnO/ZnO:Al/Al-grid architecture with minor modifications to the literature procedure (ST Kim, et al. , Sustain. Energ. Fuels 2019, 3, 709-716). was synthesized A CIGS absorber layer was deposited on Mo-coated soda-lime glass through co-evaporation of Cu, In, Ga and Se from elemental effusion cells in a vacuum evaporator at an atmospheric pressure of ^{2.7Х10 -4 Pa.} The averages [Cu]/([Ga]+[In]) and [Ga]/([Ga]+[In]) were 0.80-0.90 and 0.30-0.35, respectively, and the thickness of the CIGS layer was 1.8-2.0 μm. After deposition, the CIGS film was immersed in 0.15M KCN solution for 1-min etching, washed with deionized water, and annealed at 473K, Se. In order to deposit a CdS buffer layer (40-50 nm) on the synthesized CIGS film, a chemical bath deposition process was performed for 6 minutes using _{CdSO 4} as a Cd ion source, thiourea as a sulfur source, and NH _{3 as a complexing agent.} carried out. Then, a bilayer consisting of an i-ZnO layer (50 nm) and an Al-doped ZnO layer (ZnO:Al, 350 nm) was deposited using radio frequency magnetron sputtering. Finally, Al electrodes were deposited through thermal evaporation of Al through an aperture mask. As a control, PSCs with light absorbers containing triple cations (ie, Cs, methylammonium and formamidinium) were prepared according to previously reported literature procedures.

Example 1-3: Characteristics analysis of solar cells

J - V characteristics were measured under one-sun illumination (AM 1.5G, 100mW cm ^-2 ) using K3000 Solar Simulator (McScience Inc., Korea) and calibrated with a silicon reference cell. The power conversion efficiency (PCE) was calculated using Equation (1).

반응식 (1)

Scheme (1)

where J sc is the short-circuit current density (mA cm ^-2 ), Voc is the open-circuit voltage (V), FF is the fill factor, and P is the incident illumination power density ( incident illumination power density, mW cm ^-2 ). The external quantum efficiency was obtained using a QEX7 solar cell spectral response/QE/IPCE measurement system (PV Measurement Inc., USA).

Example 1-4: photoanode fabrication

Commercially available FTO glass (TEC-7, Pilkington) was thoroughly rinsed with 1.0M KOH aqueous solution, deionized water and ethanol. Electrodeposition of BiOI film on FTO was performed using potentiostat/galvanostat (WMPG 1000, WonATech Co., Korea); The FTO substrate was immersed in the BiOI precursor solution, and an external bias of -0.1 V (vs. Ag/AgCl) was applied to the substrate. The three-electrode configuration consists of a working electrode, a reference electrode (Ag/AgCl, 3M NaCl) and a counter electrode (stainless steel). The precursor solution was prepared by dissolving Bi(NO ₃ ) ₃ ·5H ₂ O (40 mM), HNO ₃ (3 μl ml ^-1 ) and KI (40M) in deionized water (100 ml), and containing p- benzoquinone (115.6 mM). It was prepared by adding 40 ml ethanolic solution. In order to convert BiOI to BiVO ₄ , a solution containing V was dropped on the BiOI electrode and heated in a Lindberg/Blue M muffle furnace (Fisher Scientific Corp., USA), 723 K, for 2 hours at a ramping rate of 1 K min ⁻¹ . A precursor solution was prepared by dissolving _{VO(acac) 2} (51.2 mg) in anhydrous DMSO (1 ml). After the reaction, the brown V ₂ O _{5 crust on the BiVO 4} surface was immersed in 1M NaOH solution and removed while gently stirring. Light of BiVO ₄ electrode FeOOH cocatalyst (cocatalyst) of the - for the secondary electro-deposition, dipping, while vigorously stirring the BiVO ₄ to FeSO ₄ aqueous solution (100mM), the white LED light (2mW cm ^-2) 0.3V (vs under investigation. Ag/AgCl) was applied.

Example 1-5: Fabrication of photoanode/photovoltaic tandem cells

A FeOOH/BiVO ₄ /CIGS tandem cell was fabricated by connecting the FeOOH/BiVO _{4 photoanode to the CIGS solar cell.} The CIGS solar cell was covered with a transparent waterproof epoxy. Then, to further connect the negative electrode, the Al grid was covered with Ag paste and Cu tape was attached to the side. Meanwhile, Cu tape was attached to the Mo side of CIGS and connected to the FTO side of _{FeOOH/BiVO 4 .} Finally, to block the incident light and avoid direct contact between the electrolyte solution and the conductive part of the tandem cell, an opaque epoxy resin was used on _{the other side of the FeOOH/BiVO 4} /CIGS device (Cu tape in Ag paste and FeOOH/BiVO ₄ except for the front side). When assembling the FeOOH/BiVO ₄ /Pervoskite tandem device, Cu tape was attached to the Au contact point of the hole collector (PSC) connected to the FTO side of the photoanode. In order to additionally connect the negative electrode, another Cu tape was attached to the FTO side of the PSC (electron collector). The other side of the PSC was covered with an epoxy resin to protect the solar cell from the environment.

Examples 1-6: meso Preparation of ITO electrodes

The meso ITO electrode synthesis method according to the literature (J. Odrobina, et al. , ACS Catal. 2017, 7 , 2116-2125) was modified. (i) 40 mg of ITO nanoparticles (diameter <50 nm) were dissolved in 193 μl of acetic acid/ethanol (300:748 v/v) mixture, (ii) sonicated for at least 60 min, and (iii) homogenized for 30 min. An ITO suspension (20 wt%) was prepared through the following steps. Then, the ITO suspension (20 μl) was drop-cast onto the ^{FTO substrate (shape surface area: 1 cm 2 ).} The electrode ^{was annealed at 673K at a rate of 4K min −1} for 1 hour. Another area not covered with ITO nanoparticles was covered with epoxy resin. As a control, planar ITO glass was obtained from Taewon Scientific Corp. (Korea).

Example 1-7: (Photo)electrochemical measurement

The (photo)electrochemical experiment was controlled using a potentiostat/galvanostat (WMPG 1000, WonATech Co., Korea). In the three-electrode configuration, the working electrode, reference electrode (Ag/AgCl, 3M NaCl) and counter electrode (stainless steel) were located in the same compartment. The electrolyte solution consisted of sodium phosphate buffer (100 mM, pH 7.0). When CPPE was performed ( FIGS. 3D and 16D ), the light source was a xenon lamp (λ>400 nm, P : 100 mW cm ⁻² ). All potentials were quoted for RHE using Scheme (2).

반응식 (2)

Scheme (2)

Example 1-8: Biocatalyst photoelectrochemical reaction

Cofactor regeneration reaction and water oxidation reaction were performed in two separate reactors connected by salt bridge. FeOOH/BiVO ₄ /CIGS tandem cells were immersed in phosphate buffer (100 mM, pH 7.0), and meso- ITO negative electrode was immersed in phosphate buffer (100 mM, pH 7.0) containing 0.5 mM M and 1 mM NAD ^+; The cathode was connected to the tandem cell (via a potentiostat) in a two-electrode configuration. The geometrical surface areas of CIGS, FeOOH/BiVO ₄ and meso ITO were 0.45, 4 and 1 cm ^{2 ,} respectively. When the CIGS solar cell was replaced with PSC (geometric surface area: 0.45 cm ² ), the PSC was placed outside the reaction chamber to avoid direct contact with the aqueous solution. ca. from PSC. The photoanode was immersed in the solution at a distance of 3 cm. Also, the meso- ITO cathode was connected to the tandem cell through a potentiostat. Except for the meso- ITO cathode, these tandem absorbers were irradiated with a xenon lamp (Newport Co., USA; λ>400 nm; P : 100 mW cm ^{2 ).} The NADH concentration was monitored using a V-650 UV-Vis absorption spectrophotometer (JASCO Inc., Japan); The absorption peak position and molar extinction coefficient of NADH were 340 nm and 6220M ^-1 cm ^{-1 ,} respectively. For _{biocatalytic conversion of CO 2} to formate, 0.5 mM M , 0.5 mM NAD ⁺ , 10U ml ^-1 Ts FDH and CO ₂ A phosphate buffer (100 mM, pH 7.0) was prepared; Before and during the redox reaction, the phosphate buffer _{was removed with CO 2} gas (99.999%). Formate was quantified using LC-20A prominence (Shimadzu Corp., Japan). The instrument was equipped with a refractive index detector and an Aminex HPX-87H ion exclusion column (Bio-Rad Laboratories Inc., USA). TOF _NAD+ and TTN _NAD+ were calculated according to the following equations [Schemes (3) and (4)].

반응식 (3)

Scheme (3)

반응식 (4)

Scheme (4)

Example 2: Photovoltaics and photoanodes

CIGS solar cells were synthesized through a vacuum-based-co-evaporation process. The current density-voltage ( JV ) characteristics of the CIGS solar cell are shown in FIG. 3A. Performance statistics were obtained for 20 0.45 cm ² CIGS devices ( FIG. 4 ): short-circuit current density ( J _SC ^{) of 35.68±1.20 mA cm −2} , open-circuit current density of 0.64±0.02 V circuit) voltage ( V _OC ), a fill factor (FF) of 0.65±0.03, and a power conversion efficiency (PCE) of 15.01±0.77%. The estimated J _SC is related to the integrated photocurrent density obtained from the external quantum efficiency (Fig. 5). As a control of the solar cell, an organometallic PSC (active area: 0.45 cm ² ) was prepared and the stability of PV in a long-term redox biocatalyst was investigated. PSC showed J _SC of 19.53±1.37 mA cm ⁻² , V _OC of 1.11±0.01V , FF of 56.13±2.16 and PCE of 11.41±0.92%. A JV plot of PSC is shown in Figure 3A.

To provide electrons extracted from the H ₂ O oxidation to the cathode, the nanoscale through electrodeposition of a BiOI film on a fluorine-doped tin oxide (FTO) substrate and _{thermal conversion of BiOI to BiVO 4 .} A structured BiVO ₄ photoanode was synthesized. Since the high photocurrent is advantageous for improving the target redox reaction rate in the series connection of the tandem device, _{the thickness of BiVO 4} is controlled (see the detailed results in the legend of Fig. 6, Fig. 7 and Fig. 8; Fig. 10), and BiVO _By applying an FeOOH adsorption layer (ad-layer) to ₄ (Fig. 3B), the photoanode current of FeOOH/BiVO 4 was optimized. Optical band gap of FeOOH / BiVO ₄ photoelectrode (2.4-2.5eV) (SK Kuk, et al., Adv. Energy Mater. 2019, 9, 1900029) The optical band gap (~ 1.1eV) of the single CIGS photovoltaic (B Koo, et al. , ACS Appl. Mater. Interfaces 2017, 9 , 5279-5287), we _{expected that light transmitted through FeOOH/BiVO 4} would photoactivate the CIGS layer. When a single CIGS photocell _{was exposed to FeOOH/BiVO 4} filtered light, J _SC and V _OC decreased to 20 mA cm ^-2 and 0.63 V, respectively (Fig. 3A). This means that the reduced V _OC is FeOOH / ₄ is higher than the start potential of the oxidation induced by BiVO, FeOOH / BiVO ₄ / CIGS tandem structure can lead to the H ₂ O oxidation unbiased (Figure 3A and Figure 3B). In addition, under filtered irradiation, the J _SC and V _OC of PSCs decreased to 2.01 mA cm ^-2 and 1.08 V, respectively (Fig. 3A).

Example 3: CIGS-based PEC-PV tandem structure

A single CIGS photocell and FeOOH/BiVO ₄ photoanode were electrically connected in series. Because the photovoltaic cell and the photoanode absorb photons in different regions of the solar spectrum, the PEC-PV tandem device enables a wide range of light acquisition. It was confirmed whether the photovoltage of CIGS was exhibited in FeOOH/BiVO _{4 .} Linear sweep voltammetry (linear sweep voltammetric; LSV) According to the analysis, it CIGS solar cells and similar ca. CIGS of V _OC The JV _{profile of FeOOH/BiVO 4} was shifted to the cathode by 0.62V (FIG. 3C) (FIG. 3A). In addition, the tandem device generated a photocurrent of 1.18 mA without external bias (Fig. 3D). This value is consistent with the operating current (1.20 mA) estimated from the intersection of the JV _{curve of the FeOOH/BiVO 4} photoelectrode and the CIGS solar cell (Fig. 9). The similarity of the actual and estimated photocurrents indicates that the FeOOH/BiVO ₄ photoanode and CIGS solar cells are well connected to a single tandem device without significant electrical resistance. When using a perovskite in photovoltaic components, JV curve of FeOOH / BiVO ₄ is similar ca. V _OC and the value of the PSC moved to the cathode by 1.00V (Fig. 3C) (Fig. 3A). However, due to the low photocurrent PSC (Fig. 3A and Fig. 9), the photocurrent of FeOOH / BiVO ₄ / Perovskite is lower than that of the photoelectric current FeOOH / BiVO ₄ / CIGS (Fig. 3D).

Example 4: Stability Study

_{Photoelectrochemical analysis of FeOOH/BiVO 4} /CIGS devices in different relative humidity (RH) environments by performing controlled potential photoelectrolysis (CPPE) at 0 V, a two-electrode configuration (counter electrode: a stainless steel). stability was investigated. As shown in Fig. 3D, _{the photocurrent of FeOOH/BiVO 4} /CIGS was kept constant at 40, 60 or 80% RH for 24 hours, indicating strong stability of _{FeOOH/BiVO 4 and CIGS components with respect to humidity.} In contrast, CPPE showed a deleterious effect of humidity on the photocurrent of _{FeOOH/BiVO 4 /Perovskite;} The photocurrent decay rate was ca. 7-fold higher, with a sudden drop in photocurrent at 0.3 h under 80% RH (Fig. 3D). We believe that the unstable photocurrent generation is due to the poor stability of PSCs to humidity, which has been widely reported in the PV community. Consequently, CIGS photovoltaic cells are more suitable for the practical application of redox bioconversion of solar energy.

Example 5: Cathodes

As a cathode material for NADH regeneration, meso- ITO electrodes were synthesized by accumulating ITO nanoparticles (diameter <50 nm) on FTO-coated glass and annealing at 673 K (Fig. 10A). The reason for preparing meso- ITO is to increase the electrochemically active surface area (ECSA) to improve the electron transport rate to M. The meso- ITO film exhibited a mesostructure of a nanoparticulate ITO film having a thickness of 15.4 μm ( FIGS. 10B and 11 ). In addition, the X-ray diffraction pattern of meso- ITO was consistent with the X-ray diffraction pattern of cubic ITO (JCPDS: #01-083-3350), indicating a composition without contamination of the electrode (Fig. 12). Cyclic voltammetry (CV) was used to verify the large ECSA of meso-ITO electrodes. According to the literature (Y. Wang, et al ., Chem. Soc. Rev. 2016, 45 , 5925-5950), an electrode with a large ECSA exhibits a large integral area of the CV curve due to the high capacitance of the electrode. . As shown in Fig. 10C, the area enclosed within the JV curve of the meso ITO electrode was much larger than that of the planar ITO electrode at various scan rates.

Analysis using LSV demonstrated the ability of the meso- ITO anode to reduce M in a three-electrode configuration ( meso ITO cathode as working electrode, Ag/AgCl as reference electrode, and stainless steel as counter electrode). M regio-specifically converts NAD ⁺ to enzymatically active 1,4-NADH (J. Kim, et al. , Angew. Chem. Int. Ed. 2018, 57 , 13825-13828), and M Reduction requires ^{-0.13V (vs. reversible hydrogen electrode, RHE), which is a weaker potential than NAD +} (-ca. -0.54V vs. RHE, considering overpotential) (J. Kim, CB Park, Curr. Opin) (Chem. Biol. 2019, 49 , 122-129). As shown in Fig. 10D, the presence of M in the electrolyte solution increases the cathode current at about −0.18 V (vs. RHE), indicating an electrochemical reduction of M. The cathode current increased with the addition ^{of NAD +} , which means sequential transfer of electrons from meso- ITO to NAD ⁺ through M . On the other hand, the meso- ITO electrode showed a slight change in the cathode current after adding NAD ⁺ without M ( FIG. 13 ). In addition, according to analysis using UV-Vis spectroscopy, the meso- ITO cathode successfully regenerated NADH. At an applied potential of −0.28 V (vs. RHE) , the NADH regeneration rate by meso- ITO cathode was 101.0±6.1 μM h ⁻¹ , whereas the regeneration rate by planar ITO in the presence of M ^{was 5.2±6.2 μM h −1} was only (Fig. 10E). superior performance of the meso ITO is due to the reduction of the M by meso faster than planar ITO ITO (Fig. 14). The meso- ITO and planar ITO electrodes did not produce NADH in the absence of M (Fig. 10E).

Example 6: Bias-free photoelectrochemical regeneration of NADH

Each FeOOH / BiVO ₄ / CIGS and complete tandem structure for NADH regeneration using light and refine the H ₂ O oxidized and NADH regeneration by meso ITO, as the sole energy source (i.e., FeOOH / BiVO ₄ / CIGS / meso ITO) was created. Overlaid of FeOOH/BiVO ₄ /CIGS and meso ITO shown in FIG. 15 | The unbiased redox reaction by the complete tandem apparatus was predicted according to the I |- V plot. As shown in Figure 16A, exposure to light in the tandem device (λ>400 nm, P : 100 mW cm ⁻² ) induced NADH regeneration. In control experiments in the absence of light, CIGS module, FeOOH cocatalyst or M, NADH was regenerated to a negligible extent. The photoelectrochemical performance of NADH regeneration ^{increased with increasing NAD +} concentration ( FIG. 17 ). The NADH regeneration rate of 1.21 mM h ^-1 was the highest among reports on NADH regeneration in the FDH-coupled PEC platform (Table 1).

Comparison of biocatalytic conversion efficiency of _{CO 2} to formate with cofactor regeneration in PEC platform (Photo) anode FeOOH/BiVO ₄ Co-Pi/α-Fe ₂ O ₃ Co-Pi/α-Fe ₂ O ₃ 3-jn-Si/ITO/Co-Pi No
Information (Photo) cathode meso ITO BiFeO ₃ ITO H-SiNW InP Light λ > 400 nm λ > 420 nm λ > 420 nm λ > 420 nm λ > 300 nm applied bias Electrical bias [V] 0 ^a) 0.8 ^a) 1.2 ^a) 1.8 ^a) 0.451
(vs. RHE) ^b) Chemical bias [V] 0 0.295 0.354 0.012 0 Cofactor
regeneration Cofactor type NADH NADH NADH NADH MV ^+・ Initial rate of cofactor regeneration [mM h ^-One ] 1.21 0.34 ^c) Not Available Not Available Not Available Biocatalytic CO ₂ -to-format conversion Total formate formation [mM] 5.60 2.03 0.55 0.26 0.60 TOF _cofactor [h] ^-One ] 0.236 0.04 ^c) 0.01 ^c) 0.01 ^c) Not Available TTN _cofactor 11.2 0.406 ^c) 0.55 ^c) 0.26 ^c) 0.3 ^c) Ref the present invention SK Kuk, et al. , Angew. Chem. Int. Ed. 2017, 56 , 3827-3832 D.H. Nam, et al. , Green Chem. 2016, 18 , 5989-5993 EJ Son, et al. , Chem. Commun. 2016, 52 , 9723-9726 B. A. Parkinson, P. F. Weaver, Nature 1984, 309, 148-149

In the above table, photoelectrodes are underlined, and those without underline are metal electrodes. Also, ^a) two-electrode configuration; ^b) three-electrode configuration; ^{c) means} approximate estimation according to data corroborated by the corresponding reference.

Bias-free NADH regeneration experiments in a humid environment showed lower performance _{of FeOOH/BiVO 4} /Perovskite/ meso-ITO. At below 40 and 60% RH, CIGS- and PSC-based tandem cells ^{generated NADH from NAD +} ( FIG. 16B ). However, below 80% RH, only CIGS-based devices formed NADH. The insignificant formation of NADH by perovskite tandem cells is due to the extreme lack of PSC photoactivity at high RH (Fig. 3D), and water influx into organometallic PSCs is due to the hydrolysis of organic species and the ratio of perovskite material It induces reverse decomposition (Z. Song, et al. , Adv. Energy Mater. 2016, 6 , 1600846).

Based on the widely accepted mechanism of photoelectrochemistry (C. Jiang, et al. , Chem. Soc. Rev. 2017, 46 , 4645-4660), we show that unbiased NADH regeneration from H ₂ O to NAD ⁺ electrons was considered to belong to the light-induced movement of (Fig. 16C). Solar excitation of electrons and holes occurs in the double absorber (ie FeOOH/BiVO ₄ and CIGS photoelectrode). The photoexcited holes of CIGS are annihilated through recombination with photoexcited electrons _{of FeOOH/BiVO 4 .} The excited electrons in the conduction band of CIGS have a more negative energy level than the reduction potential of M , which is a thermodynamic driving force that reduces M and regenerates NADH at the meso-ITO cathode. At the same time, FeOOH/BiVO ₄ restores the photoanode to its initial state by extracting electrons from the H _{2 O oxidation.} In terms of quasi-Fermi levels ( E F), light generates a photovoltage (V _ph = | E _F,n - E _F,h |) through the reproliferation of a few carriers at the photoelectrode. _{The total V ph} of the FeOOH/BiVO ₄ /CIGS tandem structure (~1.64 V = ~1.0 V(JH Kim, JS Lee, Adv. Mater. 2019, 31 , 1806938)+0.64 V) resulted in M reduction and H ₂ O oxidation. greater than the thermodynamic voltage (~1.34 V) for the bias-free NADH regeneration.

Example 7: Redox biocatalyst reaction of solar energy power

Based on the successful results of the above examples, the present inventors compared other FDHs (eg, FDH derived from Ancylobacter aquaticus KNK607M, Ceriporiopsis subvermispora , Moraxella sp. C-1, Paracoccus sp. 12-A or Candida boidinii ). Bias-free NADH regeneration was applied to formate conversion from _{biocatalyst CO 2} using Ts FDH showing good specificity constant (k _red /K _M ) for CO _{2 reduction.} The complete tandem structure achieved biocatalytic production of formate only under light irradiation (Fig. 18A). If CIGS, FeOOH, or BiVO ₄ is omitted in the entire device, formate is not formed, resulting in very little NADH formation (FIG. 16A). In addition, both photosynthetic components (eg, M, NAD ⁺ and Ts FDH) and CO ₂ substrate were essential for the biocatalyst formation of formate ( FIG. 18B ). These results highlight the thermodynamically favorable pathway of _{enzymatic CO 2} reduction via NADH regeneration as opposed to direct electrochemical CO _{2 reduction.}

We sought to determine the dependence of the initial rate of photo-biocatalytic CO ₂ reduction on the concentrations of Ts FDH and NAD ^{+ .} The initial reaction rate was saturated at Ts FDH concentrations above 10 ^{U ml −1} ( FIG. 19A ), indicating that the biocatalytic reaction step is the overall rate limiting. On the other hand, the initial rate of the photo-biocatalyst ^{reached a maximum at 0.5 mM NAD +} at various co-cofactor concentrations (0 to 2 mM) (Fig. 19B). Deviation from Michaelis-Menten-type behavior is due to the inhibitory effect of NADH on Ts FDH at high concentrations of cofactors (S. Kim, et al. , J. Mol. Catal. B Enzym. 2014, 102 , 9- 15). The regeneration rate of NADH in the CIGS-based tandem platform ^{increased with increasing NAD +} concentration ( FIG. 17 ).

The present inventors ^{performed a long-term photo-biocatalytic reaction using 0.5 mM NAD +} and 10 Uml ^-1 Ts FDH, which was an optimized condition from the experiment for rate-determining factors (FIG. 19). Bias-free CPPE showed the stability of a single CIGS-based fully tandem device, which achieved 72 h catalysis with 5.6 mM formate production (Fig. 16D). Total conversion rate of ^{NAD + (total turnover frequency; TOF} NAD +) and the total number of conversions _{(total turnover number; TTN NAD +} ) was estimated to be the respectively 0.236h ^-1 and 11.2. When the reaction solution was replaced at the cathode site, the photocurrent was restored in the next cycle (FIG. 20). The formate concentration was almost the same after 12 hours of reaction in the first and second cycles. According to recent studies in the field of protein engineering, it is expected that the stability problem can be solved through enzyme immobilization (SH Lee, et al. , Angew. Chem. Int. Ed. 2018, 57 , 7958-7985). For example, polymeric materials (e.g., chitosan nanoparticles ( K.-M. Yeon, et al. , Biomacromolecules 2019, 20 , 2477-2485) and polyaniline nanofibers (J. Lee, et al. , ACS Appl. Mater) Interfaces 2017, 9 , 15424-15432), cross-linking of precipitating enzymes significantly improves the stability of enzymes for 60 days because multi-point covalent bonds between enzymes inhibit their denaturation.

In addition, in the case of the PSC-based tandem structure, low photoenzyme performance was confirmed under humid conditions. _{FeOOH/BiVO 4} /perovskite/ meso- ITO at 40, 60, and 80% RH produced 4.3, 3.9, and 0 mM formate, respectively, after 72 hours of light irradiation (λ > 400 nm, P : 100 mW cm ^{-2 ) (FIG. 16E)} . On the other hand, FeOOH/BiVO ₄ /CIGS/ meso- ITO consistently produced 5.6 mM regardless of RH. These results are consistent with bias-free CPPE (Fig. 3D). Long-term exposure of PSCs to humid conditions leads to gradual functional degradation of PSCs, resulting in a decline in their photoelectrocatalytic capacity.

The FeOOH/BiVO ₄ /CIGS/ meso- ITO tandem apparatus is comparable to a state-of-the-art formate-producing biocatalytic PEC system using cofactor regeneration (Table 1). _{The three PEC cells are photoanode (eg, α-Fe 2} O ₃ , multi-junction Si) and (photo)cathode (eg, BiFeO ₃ , ITO) to regenerate NADH at a minimum 1.0 V applied bias. , composed of hydrogen-terminated Si nanowires). Another system used a p-type InP photocathode at 0.451 V (vs. RHE) ^{to regenerate the reduced form of toxic methyl viologen (MV +·} ) (BA Parkinson, PF Weaver, Nature 1984, 309 , 148-149). ). Solar-fuel conversion by FeOOH/BiVO ₄ /CIGS/ meso ITO tandem device was the most efficient in _{terms of TOF cofactor} and TTN _cofactor even under bias-free conditions.

The CIGS-based tandem device exhibited baseline efficiencies in the biocatalytic PEC systems reported so far. The present inventors have considered several directions for achieving higher photo-biocatalyst productivity. As shown in Fig. 15, the meso- ITO was maintained as a current-limiting electrode in a tandem structure. Since the strong π–π interaction between the heteroaromatic moiety of M and the electrode promotes interfacial charge transfer, the functionalization of the electrode with graphitic carbon materials (e.g., graphene hydrogel and carbon nanotube film) is M reduction rate can be improved. Also, increasing the photovoltage of a CIGS photovoltaic cell can produce a higher operating current. For example, an increase in photovoltage of 0.2V can almost double the tandem current (FIG. 15). Recent studies have focused on increasing the photovoltage (~0.8 V) of CIGS through the use of a Cd-free window layer with a large bandgap and Ga incorporation rate in the CIGS layer, Na incorporation in the Mo layer. R. Carron, et al. , Adv. Energy Mater. 2019, 9 , 1900408)

FDH protein engineering to improve stability and catalytic activity can further improve biocatalytic tandem performance. The CO ₂ -reducing activity of Ts FDH is the highest among the various FDHs, but the specific constant for _{CO 2} reduction ( k _red / K _M )[(Scheme (5)] is the constant for formate oxidation)[(Scheme (6)) ] is 3.2 times lower.

반응식 (5)

Scheme (5)

반응식 (6)

Scheme (6)

Random mutation or amino acid sequence alignment approaches have been demonstrated to improve the stability and catalytic activity of FDH (VI Tishkov, VO Popov, Biomol. Eng. 2006, 23 , 89-110). In addition to structural modification of enzymes, FDH immobilization in porous materials can preserve the intrinsic structure of enzymes and improve enzyme stability under harsh conditions (Y. Chen, et al. , Angewandte Chemie 2019, 131 , 7764-7768).

Example 8: Confirmation of hydrogen production

FeOOH/BiVO ₄ /CIGS (working electrode) and stainless steel (counter electrode) were placed in the same compartment, and then an electrolyte solution (sodium phosphate buffer, 100 mM, pH 7.0) was put into the compartment. To measure the current value, the working electrode and the counter electrode were connected to a potentiostat/galvanostat (WMPG 1000, WonATech Co., Korea), and the voltage between the two electrodes was set to 0V. The light source used at this time was a xenon lamp (λ>400nm, P : 100mW cm ^-2 ).

The CIGS-based tandem structure exhibited 1.18mA photocurrent regardless of relative humidity in the absence of bias. This means that water was oxidized to produce oxygen gas, and protons were reduced to produce hydrogen gas (FIG. 3D). On the other hand, when CIGS was changed to PSC, the photocurrent gradually decreased, with a higher rate of decrease as the relative humidity increased. This is because the structure of PSC is decomposed by water.

As described above in detail a specific part of the content of the present invention, for those of ordinary skill in the art, it is clear that this specific description is only a preferred embodiment, and the scope of the present invention is not limited thereby. will be. Accordingly, it is intended that the substantial scope of the present invention be defined by the appended claims and their equivalents.

Claims (20)

A photoelectrochemical (PEC) device comprising a photoanode, Cu(In,Ga)Se _{2 ) photovoltaic (CIGS) and a cathode.}
The photoelectrochemical (PEC) device according to claim 1, wherein the photoanode, the CIGS photovoltaic cell and the cathode form a tandem structure.
According to claim 1, wherein the photoanode is FeOOH/BiVO ₄ , NiOOH/BiVO ₄ , NiOOH/FeOOH/BiVO ₄ , α-Fe ₂ O ₃ and WO ₃ Photoelectricity, characterized in that any one selected from the group consisting of Chemical (PEC) devices.
According to claim 1, wherein the negative electrode is ITO (indium tin oxide), FTO (fluorine-doped tin oxide), stainless steel (stainless steel), TiO ₂ , Pt, glassy carbon electrode (glassy carbon electrode), carbon fabric (carbon) cloth), a photoelectrochemical (PEC) device, characterized in that at least one selected from the group consisting of carbon felt and carbon nanotube buckypaper.
5. The photoelectrochemical (PEC) device according to claim 4, wherein the ITO is mesoporous indium tin oxide ( meso ITO).
The photoelectrochemical (PEC) device according to claim 1, characterized in that it is a device for cofactor regeneration or hydrogen production.
A method of regenerating a cofactor comprising the steps of:
(a) adding a solution comprising an oxidation-type cofactor, an electron transport mediator and an electron donor to the photoelectrochemical (PEC) device of claim 1 ; and
(b) regenerating the oxidized cofactor into a reduced cofactor by irradiating the photoelectrochemical (PEC) device with a light source.
The method of claim 7, wherein the electron donor is water (H ₂ O), triethanolamine (TEOA, triethanolamine), ethylenediaminetetraacetic acid (EDTA, Ethylenediaminetetraacetic acid), citric acid (Citric acid), ascorbic acid (Ascorbic acid) and A method for regenerating a cofactor, characterized in that it is selected from the group consisting of oxalic acid.
The method according to claim 7, wherein the oxidative cofactor is selected from the group consisting of ^{NAD +} (nicotinamide adenine dinucleotide), NADP ⁺ (nicotinamide adenine dinucleotide phosphate), FAD ⁺ (flavin adenine dinucleotide) and FMN ^{+ (flavin monoucleotide).} A method of regenerating cofactors using
The method according to claim 7, wherein the electron transport mediator is selected from the group consisting of methylviologen, ruthenium(II) complex, and rhodium(III) complex.
11. The method of claim 10, wherein the rhodium (III) complex is (pentamethylcyclopentadienyl-2,2'-bipyridinechloro) rhodium (III): [Cp ^* Rh (bpy) H ₂ O] ²⁺ A method of regenerating a cofactor characterized by its characteristics.
A method of artificial photosynthesis comprising the steps of:
(a) adding a solution containing an oxidation-type cofactor, an electron transfer mediator, and an electron donor to the photoelectrochemical (PEC) device of claims 1 to 6, and then irradiating a light source to regenerate the cofactor; and
(b) preparing a useful substance by using the regenerated cofactor in a redox reaction of a substrate of an oxidoreductase.
The method of claim 12, wherein the electron donor is water (H ₂ O), triethanolamine (TEOA, triethanolamine), ethylenediaminetetraacetic acid (EDTA, Ethylenediaminetetraacetic acid), citric acid (Citric acid), ascorbic acid (Ascorbic acid) and Artificial photosynthesis method, characterized in that selected from the group consisting of oxalic acid.
The method according to claim 12, wherein the oxidative cofactor is selected from the group consisting of ^{NAD +} (nicotinamide adenine dinucleotide), NADP ⁺ (nicotinamide adenine dinucleotide phosphate), FAD ⁺ (flavin adenine dinucleotide) and FMN ^{+ (flavin monoucleotide).} artificial photosynthesis method.
13. The method of claim 12, wherein the electron transport mediator is selected from the group consisting of methylviologen, ruthenium(II) complex, and rhodium(III) complex.
The method of claim 15, wherein the rhodium (III) complex is (pentamethylcyclopentadienyl-2,2'-bipyridinechloro) rhodium (III): [Cp ^* Rh(bpy)H ₂ O] ²⁺ Artificial photosynthesis method characterized.
The method according to claim 12, wherein the oxidoreductase is formate dehydrogenase (FDH), glutamate dehydrogenase (GDH), alcohol dehydrogenase (ADH), glucose-6-phosphate dehydrogenase (G6PDH), lactic dehydrogenase (LDH), malate dehydrogenase (MDH). And SDH (succinic dehydrogenase) Artificial photosynthesis method, characterized in that selected from the group consisting of.
The method according to claim 12, wherein the regenerated cofactor is oxidized after the redox reaction in step (b) and re-added in step (a).
A method for producing hydrogen comprising adding an electrolyte solution to the photoelectrochemical (PEC) device of claim 1 , and then irradiating a light source.
20. The method of claim 19, wherein the electrolyte solution comprises water (H ₂ O) and an ionizing compound, wherein the ionizing compound is lithium chloride, potassium chloride, sodium chloride, calcium chloride, potassium nitrate, sodium nitrate, potassium sulfate, sodium sulfate and mixtures thereof. Hydrogen production method, characterized in that selected from the group consisting of.

Images