WO2023065519A1 - Bismuth vanadate-metal organic complex composite photoelectrode, and preparation method therefor and use thereof - Google Patents

Bismuth vanadate-metal organic complex composite photoelectrode, and preparation method therefor and use thereof Download PDF

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WO2023065519A1
WO2023065519A1 PCT/CN2021/139397 CN2021139397W WO2023065519A1 WO 2023065519 A1 WO2023065519 A1 WO 2023065519A1 CN 2021139397 W CN2021139397 W CN 2021139397W WO 2023065519 A1 WO2023065519 A1 WO 2023065519A1
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organic complex
bivo
photoelectrode
metal organic
metal
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French (fr)
Chinese (zh)
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熊贤强
艾成浩
梅优阳
张晓�
韩得满
李江山
程高飞
武承林
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台州学院
台州市生物医化产业研究院有限公司
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    • 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
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • 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
    • C25B11/091—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of at least one catalytic element and at least one catalytic compound; consisting of two or more catalytic elements or catalytic compounds
    • C25B11/095—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of at least one catalytic element and at least one catalytic compound; consisting of two or more catalytic elements or catalytic compounds at least one of the compounds being organic
    • 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
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C25B1/02—Hydrogen or oxygen
    • C25B1/04—Hydrogen or oxygen by electrolysis of water
    • 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
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/50—Processes
    • C25B1/55—Photoelectrolysis
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/36—Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/10—Process efficiency
    • Y02P20/133—Renewable energy sources, e.g. sunlight

Definitions

  • the invention belongs to the technical field of photoelectrodes, in particular to a bismuth vanadate-metal organic complex composite photoelectrode, a preparation method and application thereof.
  • Semiconductor photocatalytic water oxidation can combine the advantages of photocatalysis and electrocatalysis, and can split water into H 2 and O 2 under the condition of small bias voltage and sunlight irradiation.
  • semiconductor photoanodes such as ZnO, Fe2O3 , TiO2 , WO3 , CuWO4 , or BiVO4 .
  • BiVO4 bismuth vanadate
  • the loading of inorganic electrocatalysts can reduce The direct contact between the bismuth vanadate electrode and the solution reduces chemical corrosion; at the same time, the introduction of inorganic electrocatalyst can reduce the activation energy of water oxidation, increase the interface charge transfer rate, and then improve the activity of water splitting.
  • inorganic electrocatalyst technology solutions such as Shi Y, Yu Y, Yu Y, et al.
  • the object of the present invention is to provide a bismuth vanadate-metal organic complex composite photoelectrode and a preparation method thereof, the bismuth vanadate-metal organic complex composite photoelectrode provided by the invention has high structural stability, photoelectric Excellent chemical properties and high stability.
  • the invention provides a bismuth vanadate-metal organic complex composite photoelectrode, comprising a substrate and a BiVO 4 -metal organic complex composite film loaded on the surface of the substrate, the BiVO 4 -metal organic complex composite film is composed of BiVO 4 -organic metal complex particles; the BiVO 4 -organic metal complex particles include a BiVO inner core and an outer shell formed by a metal organic complex covering the inner core of BiVO ;
  • the metal-organic complex is Fe 2+ -2,5-dihydroxyterephthalic acid complex.
  • the metal organic complex has an amorphous structure.
  • the particle diameter of the BiVO 4 inner core is 100-200 nm; the thickness of the outer shell is 3-100 nm.
  • the thickness of the BiVO 4 -metal organic complex composite thin film is 1-50 ⁇ m.
  • the present invention also provides a method for preparing a bismuth vanadate-metal organic complex composite photoelectrode described in the above technical solution, comprising the following steps:
  • a BiVO4 photoelectrode is provided, the BiVO4 photoelectrode includes a substrate and a BiVO4 thin film supported on the surface of the substrate, the BiVO4 thin film is formed by BiVO4 particles;
  • the inorganic metal salt includes an inorganic ferrous salt
  • the organic ligand is 2,5-dihydroxyterephthalic acid
  • the BiVO 4 photoelectrode is immersed in the inorganic metal salt-ligand mixed solution, and the hydrothermal reaction is carried out to obtain the bismuth vanadate-metal organic complex composite photoelectrode.
  • the thickness of the BiVO 4 thin film is 500-1000 nm.
  • the particle size of the BiVO 4 particles is 100-200 nm.
  • the preparation method of the BiVO photoelectrode comprises the following steps:
  • the potassium iodide-bismuth nitrate mixed solution is mixed with the ethanol solution of p-benzoquinone to obtain electrolyte solution;
  • the substrate is used as the working electrode, the Ag/AgCl electrode is used as the reference electrode, and the platinum mesh is used as the counter electrode, and constant potential deposition is performed to obtain a BiOI photoelectrode;
  • Vanadium acetylacetonate is mixed with dimethyl sulfoxide to obtain a vanadium acetylacetonate solution;
  • the vanadium acetylacetonate solution is drop-coated on the surface of the BiOI electrode and calcined to obtain the BiVO 4 photoelectrode.
  • the inorganic ferrous salt includes ferrous chloride, ferrous sulfate or ferrous nitrate.
  • the molar ratio of the inorganic metal metal ion and the organic ligand in the inorganic metal salt-ligand mixed solution is 1:(2-3).
  • the solvent is ethanol, water and N,N-dimethylformamide; the volume ratio of ethanol, water and N,N-dimethylformamide in the solvent is 1:1:(10 ⁇ 20 ).
  • the concentration of the inorganic metal salt in the inorganic metal salt-ligand mixed solution is 8-50 mmol/L.
  • the temperature of the hydrothermal reaction is 130-150° C., and the time is 10-16 hours.
  • the present invention also provides the bismuth vanadate-metal organic complex composite photoelectrode described in the above technical scheme or the bismuth vanadate-metal organic complex composite photoelectrode obtained by the preparation method described in the above technical scheme as a catalytic electrode in photoelectric catalytic water oxidation React application.
  • the invention provides a bismuth vanadate-metal organic complex composite photoelectrode, comprising a substrate and a BiVO 4 -metal organic complex composite film loaded on the surface of the substrate, the BiVO 4 -metal organic complex composite film is composed of BiVO 4 -organic metal complex particles; the BiVO 4 -organic metal complex particles include a BiVO 4 core and a shell formed by a metal organic complex covering the BiVO 4 core; the metal organic complex is Fe 2 + -2,5-dihydroxyterephthalic acid complex.
  • the BiVO 4 -metal organic complex composite thin film is composed of BiVO 4 -metal organic complex particles
  • the BiVO 4 -metal organic complex particles include a BiVO 4 core and a BiVO 4 core coating
  • the shell formed by the metal-organic complex, the core-shell structure of the BiVO 4 -metal-organic complex particles makes the binding force of the BiVO 4 core and the shell formed by the metal-organic complex high, ensuring the formation of the BiVO 4 core and the metal-organic complex
  • the interface integrity of the shell formed by the BiVO 4 core and the metal-organic complex is improved, which is beneficial to the synchronization and uniformity of the distribution of bismuth vanadate and the metal-organic complex, and reduces the bismuth vanadate.
  • Corrosion loss improves the structural stability; at the same time, it also avoids the gap between the BiVO 4 core and the shell formed by the metal-organic complex, reduces the transfer resistance of photo-generated holes and the recombination speed of photo-generated carriers, thereby achieving a reduction The overpotential of water splitting, the effect of increasing the photocurrent density and improving the photostability.
  • metal-organic complexes can passivate the surface states on the surface of the bismuth vanadate inner core, reduce the surface recombination rate of bismuth vanadate carriers, thereby increasing the concentration of photogenerated holes at the interface between the composite photoelectrode and the electrolyte, and accelerating the composite photoelectrode and electrolyte.
  • the obtained BiVO 4 -metal organic complex composite photoelectrode has excellent photoelectric catalytic water oxidation performance.
  • the metal-organic complexes with an amorphous structure can significantly passivate the surface states on the surface of the bismuth vanadate core, reduce the surface recombination rate of the bismuth vanadate carriers, and thus improve the density of photogenerated holes at the interface between the composite photoelectrode and the electrolyte. Concentration, accelerate the composite photoelectrode and electrolyte interface water oxidation rate.
  • test results of the embodiments show that the photocurrent density of the bismuth vanadate-metal organic complex composite photoelectrode provided by the present invention is greatly improved compared with bismuth vanadate, has high structural stability, excellent photoelectrochemical performance and high chemical stability, and can effectively Improves water oxidation activity.
  • Fig. 1 is the XRD figure of BiVO4 photoelectrode and bismuth vanadate-metal organic complex compound photoelectrode in embodiment 1;
  • Fig. 2 is the XRD figure of metal organic complex in embodiment 1;
  • Fig. 3 is the XPS figure of the Fe2p element of bismuth vanadate-metal organic complex compound photoelectrode in embodiment 1;
  • Fig. 4 is the XPS figure of the Cls element of BiVO photoelectrode and bismuth vanadate-metal organic complex compound photoelectrode in embodiment 1;
  • Fig. 5 is the IR figure of BiVO photoelectrode and bismuth vanadate-metal organic complex compound photoelectrode in embodiment 1;
  • Fig. 6 is the surface carrier recombination rate constant diagram of BiVO photoelectrode and bismuth vanadate-metal organic complex composite photoelectrode under different electrode potentials in embodiment 1;
  • Fig. 7 is the SEM figure of BiVO4 photoelectrode and bismuth vanadate-metal organic complex composite photoelectrode in embodiment 2, (A) is BiVO4 photoelectrode in Fig. 7, (B) is bismuth vanadate-metal organic complex Complex compound photoelectrode;
  • Fig. 8 is the linear sweep voltammetry curve graph of BiVO 4 photoelectrode and bismuth vanadate-metal organic complex composite photoelectrode in the light-on-light-off condition in embodiment 2;
  • Fig. 9 is the current-time graph of the BiVO4 photoelectrode obtained in Example 3 and the bismuth vanadate-metal organic complex composite photoelectrode under the applied bias voltage of 0.4V (vs.Ag/AgCl);
  • Fig. 10 is a linear sweep voltammetry curve of the composite photoelectrode and the BiVO 4 photoelectrode obtained in Comparative Examples 1-2.
  • the invention provides a bismuth vanadate-metal organic complex composite photoelectrode, comprising a substrate and a BiVO 4 -metal organic complex composite film loaded on the surface of the substrate, the BiVO 4 -metal organic complex composite film is composed of BiVO 4 -organic metal complex particles; the BiVO 4 -organic metal complex particles include a BiVO inner core and an outer shell formed by a metal organic complex covering the inner core of BiVO ;
  • the metal-organic complex is Fe 2+ -2,5-dihydroxyterephthalic acid complex.
  • the bismuth vanadate-metal organic complex composite photoelectrode includes a substrate.
  • the substrate preferably includes FTO conductive glass.
  • the bismuth vanadate-metal organic complex composite photoelectrode includes a BiVO 4 -metal organic complex composite film supported on the surface of the substrate, and the BiVO 4 -metal organic complex composite film is composed of BiVO 4 - Particle composition of metal-organic complexes.
  • the thickness of the BiVO 4 -metal organic complex composite thin film is preferably 1-50 ⁇ m, more preferably 1-10 ⁇ m, even more preferably 2-5 ⁇ m.
  • the BiVO 4 -metal organic complex particle includes a BiVO 4 inner core and an outer shell formed by a metal organic complex covering the BiVO 4 inner core.
  • the particle diameter of the BiVO 4 core is preferably 100-200 nm, more preferably 120-180 nm.
  • the metal-organic complex is Fe 2+ -2,5-dihydroxyterephthalic acid complex.
  • the Fe 2+ -2,5-dihydroxyterephthalic acid complex means a complex formed by ferrous ions and 2,5-dihydroxyterephthalic acid.
  • the thickness of the shell is preferably 3-100 nm, more preferably 10-90 nm.
  • the metal organic complex preferably has an amorphous structure.
  • the present invention also provides a method for preparing a bismuth vanadate-metal organic complex composite photoelectrode described in the above technical solution, comprising the following steps:
  • a BiVO4 photoelectrode is provided, the BiVO4 photoelectrode includes a substrate and a BiVO4 thin film supported on the surface of the substrate, the BiVO4 thin film is formed by BiVO4 particles;
  • the inorganic metal salt includes an inorganic ferrous salt
  • the organic ligand is 2,5-dihydroxyterephthalic acid
  • the BiVO 4 photoelectrode is immersed in the inorganic metal salt-ligand mixed solution, and the hydrothermal reaction is carried out to obtain the bismuth vanadate-metal organic complex composite photoelectrode.
  • each reagent in the preparation method is a commercially available product well known to those skilled in the art.
  • the invention provides a BiVO 4 photoelectrode, the BiVO 4 photoelectrode includes a substrate and a BiVO 4 thin film supported on the surface of the substrate, and the BiVO 4 thin film is formed by BiVO 4 particles.
  • the substrate preferably includes FTO conductive glass.
  • FTO conductive glass In the present invention, there is no special limitation on the thickness of the substrate, and the thickness of the substrate well known to those skilled in the art can be used.
  • the BiVO 4 photoelectrode includes a BiVO 4 thin film supported on the surface of the substrate, and the BiVO 4 thin film is formed by BiVO 4 particles.
  • the thickness of the BiVO 4 thin film is preferably 500-1000 nm, more preferably 550-950 nm.
  • the particle size of the BiVO 4 particles is preferably 100-200 nm, more preferably 120-180 nm.
  • the preparation method of the BiVO photoelectrode preferably comprises the following steps:
  • the substrate is used as the working electrode, the Ag/AgCl electrode is used as the reference electrode, and the platinum mesh is used as the counter electrode, and constant potential deposition is performed to obtain a BiOI photoelectrode;
  • Vanadium acetylacetonate is mixed with dimethyl sulfoxide to obtain a vanadium acetylacetonate solution;
  • the vanadium acetylacetonate solution is drop-coated on the surface of the BiOI electrode and calcined to obtain the BiVO 4 photoelectrode.
  • the invention mixes potassium iodide aqueous solution and bismuth nitrate to obtain potassium iodide-bismuth nitrate mixed liquid.
  • the concentration of the potassium iodide aqueous solution is preferably 0.45-0.55 mol/L, more preferably 0.5 mol/L.
  • the pH value of the potassium iodide aqueous solution is preferably 1.7.
  • the reagent for adjusting the pH value of the potassium iodide aqueous solution is preferably concentrated nitric acid, and the concentration of the concentrated nitric acid is preferably 68wt.%.
  • the concentration of bismuth nitrate in the potassium iodide-bismuth nitrate mixed solution is preferably 0.05-0.07 mol/L, more preferably 0.055-0.065 mol/L, most preferably 0.06 mol/L.
  • the potassium iodide aqueous solution is preferably prepared from potassium iodide and ultrapure water.
  • the mixing of the potassium iodide aqueous solution and bismuth nitrate is preferably ultrasonic; the present invention has no special limitation on the ultrasonic, and the ultrasonic well known to those skilled in the art can be used.
  • the present invention mixes the potassium iodide-bismuth nitrate mixed solution with an ethanol solution of p-benzoquinone to obtain an electrolyte solution.
  • the concentration of p-benzoquinone in the ethanol solution of p-benzoquinone is preferably 0.25-0.35 mol/L, more preferably 0.28-0.32 mol/L, most preferably 0.3 mol/L.
  • the volume ratio of the potassium iodide-bismuth nitrate mixed solution to the p-benzoquinone solution is preferably 5:(1.8-2.2), more preferably 5:(1.9-2.1), and most preferably 5:2.
  • the substrate is used as the working electrode
  • the Ag/AgCl electrode is used as the reference electrode
  • the platinum mesh is used as the counter electrode under the condition that the electrolyte solution exists, and the constant potential deposition is performed to obtain the BiOI photoelectrode.
  • the present invention has no special limitation on the Ag/AgCl electrode and platinum mesh, and the Ag/AgCl electrode and platinum mesh well known to those skilled in the art can be used.
  • the potential of the constant potential deposition is preferably -0.05 ⁇ -0.2V, more preferably -0.08 ⁇ -1.5V, most preferably -0.1V; the time is preferably 3 ⁇ 10min, more preferably 4 ⁇ 8min, most preferably 5min.
  • the present invention preferably cleans the obtained sample to remove surface impurities; in the present invention, the cleaning reagent preferably includes deionized water.
  • the present invention has no special limitation on the cleaning, and the cleaning well known to those skilled in the art can be used.
  • the invention mixes vanadium acetylacetonate and dimethyl sulfoxide to obtain vanadium acetylacetonate solution.
  • the concentration of the vanadium acetylacetonate solution is preferably 0.08-0.12 mol/L, more preferably 0.1 mol/L.
  • the present invention drip-coats the vanadium acetylacetonate solution on the surface of the BiOI electrode, and performs calcination to obtain the BiVO 4 photoelectrode.
  • the dispensing amount of the vanadium acetylacetonate solution on the surface of the BiOI electrode is preferably 100-120 ⁇ L/cm 2 , more preferably 105-115 ⁇ L/cm 2 .
  • the temperature of the calcination is preferably 440-460°C, more preferably 445-455°C, most preferably 450°C; the time is preferably 1.5-2.5h, more preferably 1.8-2.3h, most preferably 2h.
  • the calcination is preferably performed in a muffle furnace.
  • BiOI is decomposed into Bi 2 O 3
  • vanadyl acetylacetonate is decomposed into V 2 O 5
  • the Bi 2 O 3 and V 2 O 5 undergo a high-temperature solid-state reaction to generate BiVO 4 .
  • washing is preferably included after the calcination.
  • the washing is preferably soaking the calcined sample in a sodium hydroxide solution to remove residual V 2 O 5 to obtain a BiVO 4 photoelectrode.
  • the concentration of the sodium hydroxide solution is preferably 1 mol/L.
  • the soaking temperature is preferably 18-25° C., and the soaking time is preferably 30 minutes.
  • the invention mixes the inorganic metal salt, the organic ligand and the solvent to obtain the inorganic metal salt-ligand mixed liquid.
  • the inorganic metal salt includes inorganic ferrous salt.
  • the inorganic ferrous salt preferably includes ferrous chloride, ferrous sulfate or ferrous nitrate.
  • the organic ligand is 2,5-dihydroxyterephthalic acid.
  • the molar ratio of the inorganic metal metal ion and the organic ligand in the inorganic metal salt-ligand mixed liquid is preferably 1:(2-3), more preferably 1:(2.2-2.8).
  • the solvent is preferably ethanol, water and N,N-dimethylformamide (DMF).
  • the volume ratio of ethanol, water and N,N-dimethylformamide in the solvent is preferably 1:1:(10-20).
  • the concentration of the inorganic metal salt in the inorganic metal salt-ligand mixed solution is preferably 8-50 mmol/L, more preferably 8.2-30 mmol/L.
  • the present invention immerses the BiVO 4 photoelectrode in the inorganic metal salt-ligand mixed solution, and performs a hydrothermal reaction to obtain the bismuth vanadate-organic metal complex composite photoelectrode.
  • the temperature of the hydrothermal reaction is preferably 130-150° C., more preferably 135-145° C.; the time is preferably 10-16 hours, more preferably 11-15 hours.
  • the hydrothermal reaction is preferably carried out in a stainless steel autoclave.
  • ferrous ions undergo self-assembly reaction with 2,5-dihydroxy terephthalic acid ligands to generate metal-organic complexes with amorphous structure.
  • the present invention preferably further includes: sequentially washing and drying the product obtained from the hydrothermal reaction to obtain the bismuth vanadate-metal organic complex composite photoelectrode.
  • the cleaning preferably includes washing with ethanol and washing with water alternately.
  • the drying temperature is preferably 40-65° C., more preferably 45-60° C.; the drying time is preferably 5-30 minutes, more preferably 10-25 minutes.
  • the drying equipment is preferably an oven.
  • the present invention also provides the bismuth vanadate-metal organic complex composite photoelectrode described in the above technical scheme or the bismuth vanadate-metal organic complex composite photoelectrode obtained by the preparation method described in the above technical scheme as a catalytic electrode in photoelectric catalytic water oxidation React application.
  • the present invention has no special limitation on the application, and the application of the catalytic electrode well-known to those skilled in the art in the photoelectrocatalytic water oxidation reaction can be used.
  • Potassium iodide and ultrapure water were mixed, and the concentrated nitric acid with a concentration of 68wt% was used to adjust the pH value to 1.7 to obtain a potassium iodide aqueous solution with a concentration of 0.5mol/L; bismuth nitrate was mixed with the potassium iodide aqueous solution, and ultrasonically dissolved to obtain bismuth nitrate Concentration is the potassium iodide-bismuth nitrate mixed solution of 0.06mol/L;
  • P-benzoquinone is mixed with ethanol, and ultrasonically dissolved to obtain an ethanol solution of p-benzoquinone with a p-benzoquinone concentration of 0.3mol/L;
  • Electrodeposition is performed at a potential of -0.1V for 5 minutes. After the deposition is completed, the surface impurities are cleaned with deionized water to obtain a BiOI photoelectrode;
  • Vanadium acetylacetonate was mixed with dimethyl sulfoxide to obtain a vanadium acetylacetonate solution with a concentration of 0.1mol/L, and 100 ⁇ L of the vanadium acetylacetonate solution was pipetted onto the surface of the BiOI electrode (vanadium acetylacetonate The drop coating amount of the solution on the surface of the BiOI electrode is 100 ⁇ L/cm 2 ), and then placed in a muffle furnace, calcined at 450°C for 2 hours, cooled to room temperature naturally, and the obtained product was taken out, and placed in a 1mol/L sodium hydroxide solution , soaked at room temperature (25°C) for 30 minutes to remove residual V 2 O 5 and obtain a BiVO 4 photoelectrode;
  • the obtained BiVO 4 photoelectrode was placed in a stainless steel autoclave, and the conductive surface leaned against the inner lining of the stainless steel autoclave, and the inorganic ferrous salt-ligand solution was added to the inner lining of the stainless steel autoclave until it was submerged.
  • the BiVO 4 photoelectrode was subjected to a hydrothermal reaction at 120°C for 12 hours. After the reaction, the obtained hydrothermal reaction product was taken out, rinsed three times with ethanol and deionized water, and dried at 60°C for 30 minutes to obtain the bismuth vanadate-metal Organic complex compound photoelectrode.
  • the BiVO 4 photoelectrode and the bismuth vanadate-metal-organic complex composite photoelectrode in Example 1 were tested by X-ray diffraction, and the obtained XRD pattern is shown in FIG. 1 .
  • the diffraction peaks at 28.9°, 30.5°, 34.5°, 35.1°, 40.2° and 42.4° correspond to bismuth monoclinic vanadate, and the PDF card number is 14-0688; the remaining diffraction peaks are The peak can well correspond to SnO 2 ; in addition, no diffraction peaks of other substances are found, indicating that the prepared bismuth vanadate is a pure phase; the position of the diffraction peak of the bismuth vanadate-metal organic complex composite photoelectrode is consistent with that of pure BiVO 4 , no diffraction peaks of other substances appeared, indicating that the supported Fe-based metal-organic complexes were either amorphous or had a low loading
  • the metal-organic complex in the hydrothermal reaction kettle was obtained by centrifugation, ethanol and water washing, and the obtained metal-organic complex was measured by X-ray diffractometer. Crystallinity, the obtained XRD pattern is shown in Figure 2. It can be seen from Fig. 2 that a very broad diffraction peak appears on the XRD pattern of the metal-organic complex, indicating that the pure metal-organic complex has an amorphous structure.
  • FIG. 3 is bismuth vanadate- The XPS diagram of the Fe2p element of the metal organic complex composite photoelectrode
  • FIG. 4 is the XPS diagram of the C1s element of the BiVO 4 photoelectrode and the bismuth vanadate-metal organic complex composite photoelectrode in Example 1.
  • the BiVO 4 photoelectrode and bismuth vanadate-metal-organic complex composite photoelectrode were tested by infrared spectroscopy, and the obtained IR diagram is shown in Figure 5. It can be seen from Figure 5 that the bismuth vanadate-metal organic complex composite photoelectrode has some new peaks at the wavenumbers of 1556, 1415, 1240, 1200, 1112, 1031, 560, and 514cm -1 , among which the peak at 1556cm -1 The peaks can be attributed to the asymmetric stretching vibrations of the carboxyl group, the series of peaks at 500-800 cm -1 originate from the vibrations of the benzene ring, and the peak at 1112 cm -1 originates from the C-OH vibrations; combining all these characterizations, it can be well The confirmation of the presence of metal-organic complexes.
  • the surface carrier recombination rate constants of the BiVO 4 photoelectrode and the bismuth vanadate-metal organic complex composite photoelectrode were tested at different electrode potentials, and the test results are shown in Figure 6.
  • the bismuth vanadate-metal organic complex composite photoelectrode provided by the invention has lower surface carrier recombination rate constants at different electrode potentials, indicating that the bismuth vanadate-metal organic complex composite photoelectrode provided by the invention
  • the electrode can significantly increase the concentration of photogenerated holes at the interface between the composite photoelectrode and the electrolyte, which is beneficial to accelerate the rate of interfacial water oxidation.
  • BiVO4 photoelectrode is prepared
  • the obtained BiVO 4 photoelectrode was placed in a stainless steel autoclave, and the conductive surface leaned against the inner lining of the stainless steel autoclave, and the inorganic ferrous salt-ligand solution was added to the inner lining of the stainless steel autoclave until it was submerged.
  • the BiVO 4 photoelectrode was subjected to a hydrothermal reaction at 120°C for 8 hours. After the reaction, the obtained hydrothermal reaction product was taken out, rinsed three times with ethanol and deionized water, and dried at 60°C for 30 minutes to obtain the bismuth vanadate-metal Organic complex compound photoelectrode.
  • the BiVO photoelectrode and the bismuth vanadate-metal-organic complex composite photoelectrode in Example 2 are subjected to scanning electron microscopy, and the resulting SEM figure is shown in Fig. 7, ( A) in Fig. 7 is the BiVO photoelectrode, (B ) is a bismuth vanadate-metal organic complex composite photoelectrode.
  • BiVO 4 is a nanoparticle with a smooth surface; it can be seen from (B) of Figure 7 that the metal-organic complexes are evenly loaded on the surface of BiVO 4 particles, forming a stable core-shell structure, indicating 2, 5-dihydroxyterephthalic acid can be used as a coupling agent to firmly adhere metal-organic complexes to the surface of BiVO 4 particles, wherein the BiVO 4 nanoparticles have a particle size of 100-200 nm and a shell thickness of 3-100 nm.
  • the photocurrent of bismuth vanadate-metal-organic complex composite photoelectrode is significantly improved compared with the unmodified BiVO 4 photoelectrode, for example, at 0.4V (vs.Ag/AgCl) bias,
  • the current density of bismuth-metal-organic complex composite photoelectrode reaches 1.38mA ⁇ cm -2 , which is 4.6 times that of BiVO 4 photoelectrode.
  • BiVO4 photoelectrode is prepared
  • the obtained BiVO 4 photoelectrode was placed in a stainless steel autoclave, and the conductive surface leaned against the inner lining of the stainless steel autoclave, and the inorganic ferrous salt-ligand solution was added to the inner lining of the stainless steel autoclave until it was submerged.
  • the BiVO 4 photoelectrode was subjected to a hydrothermal reaction at 120°C for 12 hours. After the reaction, the obtained hydrothermal reaction product was taken out, rinsed three times with ethanol and deionized water, and dried at 60°C for 30 minutes to obtain the bismuth vanadate-metal Organic complex compound photoelectrode.
  • the current density of the bismuth vanadate-metal organic complex composite photoelectrode is higher than that of bismuth vanadate, and the current density of the bismuth vanadate-metal organic complex composite photoelectrode changes less with time, and the current density has almost no decay after 3 hours. It shows that the uniform loading of metal-organic complexes can effectively improve the stability and activity of bismuth vanadate electrodes, which shows that bismuth vanadate-metal-organic complex composite photoelectrodes have great application potential in the field of photocatalytic water splitting.
  • the concentration of ferrous chloride in the inorganic ferrous salt-ligand mixed solution is 44.44mol/L, and the concentration of the ligand is 22.22mol/L, all the other technical means are consistent with embodiment 2, obtain composite photoelectrode, wherein, composite photoelectric The metal-organic complexes in the pole are crystalline.
  • the concentration of ferrous chloride in the inorganic ferrous salt-ligand mixed solution is 66.66mol/L, and the concentration of the ligand is 22.22mol/L.
  • the rest of the technical means are consistent with Example 2 to obtain a composite photoelectrode, wherein the composite photoelectric The metal-organic complexes in the pole are crystalline.
  • the linear sweep voltammetry test was carried out on the composite photoelectrode and the BiVO 4 photoelectrode obtained in Comparative Examples 1-2, and the obtained linear sweep voltammetry curve is shown in FIG. 10 .
  • the metal-organic complexes of crystalline form have an inhibitory effect on the water-splitting performance of bismuth vanadate; further analysis shows that in the present invention, when the concentration of organic ligands increases, the metal-organic complexes of amorphous structure are obtained, The water splitting performance of the bismuth vanadate-based bismuth vanadate-metal organic complex compound photoelectrode can be better improved.

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Abstract

The present invention belongs to the technical field of photoelectrodes, and particularly relates to a bismuth vanadate-metal organic complex composite photoelectrode, and a preparation method therefor and the use thereof. The bismuth vanadate-metal organic complex composite photoelectrode provided in the present invention comprises a substrate and a BiVO4-metal organic complex composite film loaded on the surface of the substrate, wherein the BiVO4-metal organic complex composite film is composed of BiVO4-metal organic complex particles; the BiVO4-metal organic complex particle comprises a BiVO4 inner core and an outer shell which is formed by a metal organic complex and coats the BiVO4 inner core; and the metal organic complex is a Fe2+-2,5-dihydroxy terephthalic acid complex. The bismuth vanadate-metal organic complex composite photoelectrode provided in the present invention has the characteristics of a high structural stability, a good photoelectrochemical performance and a high chemical stability.

Description

一种钒酸铋-金属有机配合物复合光电极及其制备方法和应用A bismuth vanadate-metal organic complex composite photoelectrode and its preparation method and application
本申请要求于2021年10月18日提交中国专利局、申请号为CN202111207698.0、发明名称为“一种钒酸铋-金属有机配合物复合光电极及其制备方法和应用”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。This application requires submission of a Chinese patent application to the China Patent Office on October 18, 2021 with the application number CN202111207698.0 and the title of the invention "a bismuth vanadate-metal organic complex composite photoelectrode and its preparation method and application" priority, the entire contents of which are incorporated in this application by reference.
技术领域technical field
本发明属于光电极技术领域，特别涉及一种钒酸铋-金属有机配合物复合光电极及其制备方法和应用。The invention belongs to the technical field of photoelectrodes, in particular to a bismuth vanadate-metal organic complex composite photoelectrode, a preparation method and application thereof.
背景技术Background technique
半导体光电催化水氧化能够结合光催化和电催化的优势，能够在少量偏压和太阳光照射条件下将水分解为H 2和O 2。目前，研究人员已经开发了多种用于半导体光电催化水氧化的半导体光阳极，如ZnO、Fe 2O 3、TiO 2、WO 3、CuWO 4或BiVO 4。其中，单斜结构的钒酸铋(BiVO 4)由于带隙(约为2.4eV)窄、光谱吸收范围宽而得到研究者的注意。 Semiconductor photocatalytic water oxidation can combine the advantages of photocatalysis and electrocatalysis, and can split water into H 2 and O 2 under the condition of small bias voltage and sunlight irradiation. Currently, researchers have developed a variety of semiconductor photoanodes for semiconductor photocatalytic water oxidation, such as ZnO, Fe2O3 , TiO2 , WO3 , CuWO4 , or BiVO4 . Among them, bismuth vanadate (BiVO 4 ) with a monoclinic structure has attracted researchers' attention due to its narrow band gap (about 2.4eV) and wide spectral absorption range.
实现钒酸铋光电极的工业应用仍存在两个关键问题：钒酸铋的稳定性较差，在碱性溶液中易发生溶解腐蚀，光照下则易发生光腐蚀，极大地限制了其长时间的稳定性；钒酸铋/溶液界面的水氧化反应牵涉到四电子转移，该反应在动力学上极其缓慢，导致水分解的活性较弱。针对这两个问题，最常用的一种方法是在钒酸铋电极表面负载无机电催化剂，如在钒酸铋电极表面负载FeOOH、CoPi、NiFe-LDH或NiOOH，无机电催化剂的负载，可以减少钒酸铋电极与溶液的直接接触，进而减少化学腐蚀；同时，无机电催化剂的引入可以降低水氧化的活化能，提高界面电荷转移速度，进而提高水分解的活性。但是，目前存在的无机电催化剂技术方案(如Shi Y,Yu Y,Yu Y,et al.Boosting Photoelectrochemical Water Oxidation Activity and Stability of Mo-Doped BiVO 4 through the Uniform Assembly Coating of NiFe–Phenolic Networks[J].ACS Energy Letters,2018:acsenergylett.8b00855.)中，无机电催化剂包覆钒酸铋不均匀，容易导致溶液中的离子渗透至钒酸铋层而发生化学腐蚀，结构稳定性差，故而 光电化学性能不佳。 There are still two key problems in the industrial application of bismuth vanadate photoelectrodes: the stability of bismuth vanadate is poor, it is prone to dissolution corrosion in alkaline solution, and it is prone to photocorrosion under light, which greatly limits its long-term stability. The water oxidation reaction at the bismuth vanadate/solution interface involves four-electron transfer, which is kinetically extremely slow, resulting in a weak activity for water splitting. For these two problems, the most commonly used method is to load inorganic electrocatalysts on the surface of bismuth vanadate electrodes, such as loading FeOOH, CoPi, NiFe-LDH or NiOOH on the surface of bismuth vanadate electrodes. The loading of inorganic electrocatalysts can reduce The direct contact between the bismuth vanadate electrode and the solution reduces chemical corrosion; at the same time, the introduction of inorganic electrocatalyst can reduce the activation energy of water oxidation, increase the interface charge transfer rate, and then improve the activity of water splitting. However, currently existing inorganic electrocatalyst technology solutions (such as Shi Y, Yu Y, Yu Y, et al. Boosting Photoelectrochemical Water Oxidation Activity and Stability of Mo-Doped BiVO 4 through the Uniform Assembly Coating of NiFe–Phenolic Networks[J] .ACS Energy Letters, 2018: acsenergylett.8b00855.), the coating of bismuth vanadate by inorganic electrocatalyst is not uniform, which will easily lead to the penetration of ions in the solution into the bismuth vanadate layer and cause chemical corrosion, poor structural stability, so the photoelectrochemical performance bad.
发明内容Contents of the invention
有鉴于此，本发明的目的在于提供一种钒酸铋-金属有机配合物复合光电极及其制备方法，本发明提供的钒酸铋-金属有机配合物复合光电极具有结构稳定性高、光电化学性能优良且稳定性高的特点。In view of this, the object of the present invention is to provide a bismuth vanadate-metal organic complex composite photoelectrode and a preparation method thereof, the bismuth vanadate-metal organic complex composite photoelectrode provided by the invention has high structural stability, photoelectric Excellent chemical properties and high stability.
为了实现上述发明的目的，本发明提供以下技术方案：In order to realize the purpose of the foregoing invention, the present invention provides the following technical solutions:
本发明提供了一种钒酸铋-金属有机配合物复合光电极，包括基底和负载在所述基底表面的BiVO 4-金属有机配合物复合薄膜，所述BiVO 4-金属有机配合物复合薄膜由BiVO 4-金属有机配合物颗粒构成；所述BiVO 4-金属有机配合物颗粒包括BiVO 4内核和包覆所述BiVO 4内核的金属有机配合物形成的外壳； The invention provides a bismuth vanadate-metal organic complex composite photoelectrode, comprising a substrate and a BiVO 4 -metal organic complex composite film loaded on the surface of the substrate, the BiVO 4 -metal organic complex composite film is composed of BiVO 4 -organic metal complex particles; the BiVO 4 -organic metal complex particles include a BiVO inner core and an outer shell formed by a metal organic complex covering the inner core of BiVO ;
所述金属有机配合物为Fe 2+-2,5-二羟基对苯二甲酸络合物。 The metal-organic complex is Fe 2+ -2,5-dihydroxyterephthalic acid complex.
优选的，所述金属有机配合物为无定型结构。Preferably, the metal organic complex has an amorphous structure.
优选的，所述BiVO 4内核的粒径为100～200nm；所述外壳的厚度为3～100nm。 Preferably, the particle diameter of the BiVO 4 inner core is 100-200 nm; the thickness of the outer shell is 3-100 nm.
优选的，所述BiVO 4-金属有机配合物复合薄膜的厚度为1～50μm。 Preferably, the thickness of the BiVO 4 -metal organic complex composite thin film is 1-50 μm.
本发明还提供了上述技术方案所述钒酸铋-金属有机配合物复合光电极的制备方法，包括以下步骤：The present invention also provides a method for preparing a bismuth vanadate-metal organic complex composite photoelectrode described in the above technical solution, comprising the following steps:
提供BiVO 4光电极，所述BiVO 4光电极包括基底和负载于所述基底表面的BiVO 4薄膜，所述BiVO 4薄膜由BiVO 4颗粒形成； A BiVO4 photoelectrode is provided, the BiVO4 photoelectrode includes a substrate and a BiVO4 thin film supported on the surface of the substrate, the BiVO4 thin film is formed by BiVO4 particles;
将无机金属盐、有机配体和溶剂混合，得到无机金属盐-配体混合液；所述无机金属盐包括无机亚铁盐；所述有机配体为2,5-二羟基对苯二甲酸；mixing an inorganic metal salt, an organic ligand and a solvent to obtain an inorganic metal salt-ligand mixed liquid; the inorganic metal salt includes an inorganic ferrous salt; the organic ligand is 2,5-dihydroxyterephthalic acid;
将BiVO 4光电极置于无机金属盐-配体混合液浸没，进行水热反应，得到所述钒酸铋-金属有机配合物复合光电极。 The BiVO 4 photoelectrode is immersed in the inorganic metal salt-ligand mixed solution, and the hydrothermal reaction is carried out to obtain the bismuth vanadate-metal organic complex composite photoelectrode.
优选的，所述BiVO 4薄膜的厚度为500～1000nm。 Preferably, the thickness of the BiVO 4 thin film is 500-1000 nm.
优选的，所述BiVO 4颗粒的粒度为100～200nm。 Preferably, the particle size of the BiVO 4 particles is 100-200 nm.
优选的，所述BiVO 4光电极的制备方法，包括以下步骤： Preferably, the preparation method of the BiVO photoelectrode comprises the following steps:
将碘化钾水溶液与硝酸铋混合，得到碘化钾-硝酸铋混合液；Mix potassium iodide aqueous solution with bismuth nitrate to obtain potassium iodide-bismuth nitrate mixed solution;
将所述碘化钾-硝酸铋混合液和对苯醌的乙醇溶液混合，得到电解质 溶液；The potassium iodide-bismuth nitrate mixed solution is mixed with the ethanol solution of p-benzoquinone to obtain electrolyte solution;
在所述电解质溶液存在条件下，以基底为工作电极、Ag/AgCl电极为参比电极、铂网为对电极，进行恒电位沉积，得到BiOI光电极；In the presence of the electrolyte solution, the substrate is used as the working electrode, the Ag/AgCl electrode is used as the reference electrode, and the platinum mesh is used as the counter electrode, and constant potential deposition is performed to obtain a BiOI photoelectrode;
将乙酰丙酮钒与二甲基亚砜混合，得到乙酰丙酮钒溶液；Vanadium acetylacetonate is mixed with dimethyl sulfoxide to obtain a vanadium acetylacetonate solution;
将所述乙酰丙酮钒溶液滴涂在所述BiOI电极表面，进行煅烧，得到所述BiVO 4光电极。 The vanadium acetylacetonate solution is drop-coated on the surface of the BiOI electrode and calcined to obtain the BiVO 4 photoelectrode.
优选的，所述无机亚铁盐包括氯化亚铁、硫酸亚铁或硝酸亚铁。Preferably, the inorganic ferrous salt includes ferrous chloride, ferrous sulfate or ferrous nitrate.
优选的，所述无机金属盐-配体混合液中无机金属金属离子和有机配体的摩尔比为1：(2～3)。Preferably, the molar ratio of the inorganic metal metal ion and the organic ligand in the inorganic metal salt-ligand mixed solution is 1:(2-3).
优选的，所述溶剂为乙醇、水和N,N-二甲基甲酰胺；所述溶剂中乙醇、水和N,N-二甲基甲酰胺的体积比为1：1：(10～20)。Preferably, the solvent is ethanol, water and N,N-dimethylformamide; the volume ratio of ethanol, water and N,N-dimethylformamide in the solvent is 1:1:(10～20 ).
优选的，所述无机金属盐-配体混合液中无机金属盐的浓度为8～50mmol/L。Preferably, the concentration of the inorganic metal salt in the inorganic metal salt-ligand mixed solution is 8-50 mmol/L.
优选的，所述水热反应的温度为130～150℃，时间为10～16h。Preferably, the temperature of the hydrothermal reaction is 130-150° C., and the time is 10-16 hours.
本发明还提供了上述技术方案所述钒酸铋-金属有机配合物复合光电极或上述技术方案所述制备方法得到的钒酸铋-金属有机配合物复合光电极作为催化电极在光电催化水氧化反应中的应用。The present invention also provides the bismuth vanadate-metal organic complex composite photoelectrode described in the above technical scheme or the bismuth vanadate-metal organic complex composite photoelectrode obtained by the preparation method described in the above technical scheme as a catalytic electrode in photoelectric catalytic water oxidation React application.
本发明提供了一种钒酸铋-金属有机配合物复合光电极，包括基底和负载在所述基底表面的BiVO 4-金属有机配合物复合薄膜，所述BiVO 4-金属有机配合物复合薄膜由BiVO 4-金属有机配合物颗粒构成；所述BiVO 4-金属有机配合物颗粒包括BiVO 4内核和包覆所述BiVO 4内核的金属有机配合物形成的外壳；所述金属有机配合物为Fe 2+-2,5-二羟基对苯二甲酸络合物。 The invention provides a bismuth vanadate-metal organic complex composite photoelectrode, comprising a substrate and a BiVO 4 -metal organic complex composite film loaded on the surface of the substrate, the BiVO 4 -metal organic complex composite film is composed of BiVO 4 -organic metal complex particles; the BiVO 4 -organic metal complex particles include a BiVO 4 core and a shell formed by a metal organic complex covering the BiVO 4 core; the metal organic complex is Fe 2 + -2,5-dihydroxyterephthalic acid complex.
在本发明中，所述BiVO 4-金属有机配合物复合薄膜由BiVO 4-金属有机配合物颗粒构成，所述BiVO 4-金属有机配合物颗粒包括BiVO 4内核和包覆所述BiVO 4内核的金属有机配合物形成的外壳，所述BiVO 4-金属有机配合物颗粒的核壳结构使得BiVO 4内核与金属有机配合物形成的外壳的结合力高，确保了BiVO 4内核与金属有机配合物形成的外壳之间紧密连接，同时改善了BiVO 4内核与金属有机配合物形成的外壳的界面完整性，有利于钒酸铋与金属有机配合物分布的同步性和均匀性，降低了钒酸 铋的腐蚀损失，提高了结构稳定性；同时，还避免了BiVO 4内核与金属有机配合物形成的外壳之间的间隙，降低了光生空穴的转移阻力和光生载流子的复合速度，从而达到降低水分解的过电位、增加光电流密度、提高光稳定性的效果。而且，金属有机配合物能够钝化钒酸铋内核表面的表面态，降低钒酸铋载流子的表面复合速率，从而提高了复合光电极与电解质界面光生空穴的浓度，加速复合光电极与电解质界面水氧化速率；同时，金属有机配合物形成的外壳可以加速界面水分子的活化，导致界面载流子转移速率提升，从而提高钒酸铋-金属有机配合物复合光电极的水分解活性，使所得BiVO 4-金属有机配合物复合光电极具有优良的光电催化水氧化性能。 In the present invention, the BiVO 4 -metal organic complex composite thin film is composed of BiVO 4 -metal organic complex particles, and the BiVO 4 -metal organic complex particles include a BiVO 4 core and a BiVO 4 core coating The shell formed by the metal-organic complex, the core-shell structure of the BiVO 4 -metal-organic complex particles makes the binding force of the BiVO 4 core and the shell formed by the metal-organic complex high, ensuring the formation of the BiVO 4 core and the metal-organic complex At the same time, the interface integrity of the shell formed by the BiVO 4 core and the metal-organic complex is improved, which is beneficial to the synchronization and uniformity of the distribution of bismuth vanadate and the metal-organic complex, and reduces the bismuth vanadate. Corrosion loss improves the structural stability; at the same time, it also avoids the gap between the BiVO 4 core and the shell formed by the metal-organic complex, reduces the transfer resistance of photo-generated holes and the recombination speed of photo-generated carriers, thereby achieving a reduction The overpotential of water splitting, the effect of increasing the photocurrent density and improving the photostability. Moreover, metal-organic complexes can passivate the surface states on the surface of the bismuth vanadate inner core, reduce the surface recombination rate of bismuth vanadate carriers, thereby increasing the concentration of photogenerated holes at the interface between the composite photoelectrode and the electrolyte, and accelerating the composite photoelectrode and electrolyte. The oxidation rate of electrolyte interface water; at the same time, the shell formed by the metal-organic complex can accelerate the activation of interfacial water molecules, resulting in an increase in the interface carrier transfer rate, thereby improving the water splitting activity of the bismuth vanadate-metal-organic complex composite photoelectrode. The obtained BiVO 4 -metal organic complex composite photoelectrode has excellent photoelectric catalytic water oxidation performance.
进一步的，无定型结构的金属有机配合物更是显著钝化钒酸铋内核表面的表面态，降低钒酸铋载流子的表面复合速率，从而提高了复合光电极与电解质界面光生空穴的浓度，加速复合光电极与电解质界面水氧化速率。Furthermore, the metal-organic complexes with an amorphous structure can significantly passivate the surface states on the surface of the bismuth vanadate core, reduce the surface recombination rate of the bismuth vanadate carriers, and thus improve the density of photogenerated holes at the interface between the composite photoelectrode and the electrolyte. Concentration, accelerate the composite photoelectrode and electrolyte interface water oxidation rate.
实施例测试结果表明，本发明提供的钒酸铋-金属有机配合物复合光电极的光电流密度较钒酸铋有大幅提高，结构稳定性高、光电化学性能优良且化学稳定性高，可以有效改善水氧化活性。The test results of the embodiments show that the photocurrent density of the bismuth vanadate-metal organic complex composite photoelectrode provided by the present invention is greatly improved compared with bismuth vanadate, has high structural stability, excellent photoelectrochemical performance and high chemical stability, and can effectively Improves water oxidation activity.
说明书附图Instructions attached
图1为实施例1中的BiVO 4光电极和钒酸铋-金属有机配合物复合光电极的XRD图； Fig. 1 is the XRD figure of BiVO4 photoelectrode and bismuth vanadate-metal organic complex compound photoelectrode in embodiment 1;
图2为实施例1中金属有机配合物的XRD图；Fig. 2 is the XRD figure of metal organic complex in embodiment 1;
图3为实施例1中钒酸铋-金属有机配合物复合光电极的Fe2p元素的XPS图；Fig. 3 is the XPS figure of the Fe2p element of bismuth vanadate-metal organic complex compound photoelectrode in embodiment 1;
图4为实施例1中BiVO 4光电极和钒酸铋-金属有机配合物复合光电极的C1s元素的XPS图； Fig. 4 is the XPS figure of the Cls element of BiVO photoelectrode and bismuth vanadate-metal organic complex compound photoelectrode in embodiment 1;
图5为实施例1中BiVO 4光电极和钒酸铋-金属有机配合物复合光电极的IR图； Fig. 5 is the IR figure of BiVO photoelectrode and bismuth vanadate-metal organic complex compound photoelectrode in embodiment 1;
图6为实施例1中BiVO 4光电极和钒酸铋-金属有机配合物复合光电极在不同电极电位下的表面载流子复合速率常数图； Fig. 6 is the surface carrier recombination rate constant diagram of BiVO photoelectrode and bismuth vanadate-metal organic complex composite photoelectrode under different electrode potentials in embodiment 1;
图7为实施例2中的BiVO 4光电极和钒酸铋-金属有机配合物复合光 电极的SEM图，图7中(A)为BiVO 4光电极，(B)为钒酸铋-金属有机配合物复合光电极； Fig. 7 is the SEM figure of BiVO4 photoelectrode and bismuth vanadate-metal organic complex composite photoelectrode in embodiment 2, (A) is BiVO4 photoelectrode in Fig. 7, (B) is bismuth vanadate-metal organic complex Complex compound photoelectrode;
图8为实施例2中BiVO 4光电极和钒酸铋-金属有机配合物复合光电极在光开-光关条件下的线性扫描伏安曲线图； Fig. 8 is the linear sweep voltammetry curve graph of BiVO 4 photoelectrode and bismuth vanadate-metal organic complex composite photoelectrode in the light-on-light-off condition in embodiment 2;
图9为实施例3所得BiVO 4光电极和钒酸铋-金属有机配合物复合光电极在0.4V(vs.Ag/AgCl)外加偏压下的电流-时间曲线图； Fig. 9 is the current-time graph of the BiVO4 photoelectrode obtained in Example 3 and the bismuth vanadate-metal organic complex composite photoelectrode under the applied bias voltage of 0.4V (vs.Ag/AgCl);
图10为对比例1～2所得复合光电极和BiVO 4光电极的线性扫描伏安曲线图。 Fig. 10 is a linear sweep voltammetry curve of the composite photoelectrode and the BiVO 4 photoelectrode obtained in Comparative Examples 1-2.
具体实施方式Detailed ways
本发明提供了一种钒酸铋-金属有机配合物复合光电极，包括基底和负载在所述基底表面的BiVO 4-金属有机配合物复合薄膜，所述BiVO 4-金属有机配合物复合薄膜由BiVO 4-金属有机配合物颗粒构成；所述BiVO 4-金属有机配合物颗粒包括BiVO 4内核和包覆所述BiVO 4内核的金属有机配合物形成的外壳； The invention provides a bismuth vanadate-metal organic complex composite photoelectrode, comprising a substrate and a BiVO 4 -metal organic complex composite film loaded on the surface of the substrate, the BiVO 4 -metal organic complex composite film is composed of BiVO 4 -organic metal complex particles; the BiVO 4 -organic metal complex particles include a BiVO inner core and an outer shell formed by a metal organic complex covering the inner core of BiVO ;
所述金属有机配合物为Fe 2+-2,5-二羟基对苯二甲酸络合物。 The metal-organic complex is Fe 2+ -2,5-dihydroxyterephthalic acid complex.
在本发明中，所述钒酸铋-金属有机配合物复合光电极包括基底。在本发明中，所述基底优选包括FTO导电玻璃。本发明对所述基底的厚度没有特殊限定，采用本领域技术人员熟知的基底厚度即可。In the present invention, the bismuth vanadate-metal organic complex composite photoelectrode includes a substrate. In the present invention, the substrate preferably includes FTO conductive glass. In the present invention, there is no special limitation on the thickness of the substrate, and the thickness of the substrate well known to those skilled in the art can be used.
在本发明中，所述钒酸铋-金属有机配合物复合光电极包括负载在所述基底表面的BiVO 4-金属有机配合物复合薄膜，所述BiVO 4-金属有机配合物复合薄膜由BiVO 4-金属有机配合物颗粒构成。在本发明中，所述BiVO 4-金属有机配合物复合薄膜的厚度优选为1～50μm，更优选为1～10μm，再优选为2～5μm。 In the present invention, the bismuth vanadate-metal organic complex composite photoelectrode includes a BiVO 4 -metal organic complex composite film supported on the surface of the substrate, and the BiVO 4 -metal organic complex composite film is composed of BiVO 4 - Particle composition of metal-organic complexes. In the present invention, the thickness of the BiVO 4 -metal organic complex composite thin film is preferably 1-50 μm, more preferably 1-10 μm, even more preferably 2-5 μm.
在本发明中，所述BiVO 4-金属有机配合物颗粒包括BiVO 4内核和包覆所述BiVO 4内核的金属有机配合物形成的外壳。 In the present invention, the BiVO 4 -metal organic complex particle includes a BiVO 4 inner core and an outer shell formed by a metal organic complex covering the BiVO 4 inner core.
在本发明中，所述BiVO 4内核的粒径优选为100～200nm，更优选为120～180nm。 In the present invention, the particle diameter of the BiVO 4 core is preferably 100-200 nm, more preferably 120-180 nm.
在本发明中，所述金属有机配合物为Fe 2+-2,5-二羟基对苯二甲酸络合物。在本发明中，所述Fe 2+-2,5-二羟基对苯二甲酸络合物的意思为亚铁离子与2,5-二羟基对苯二甲酸形成的络合物。在本发明中，所述外壳的厚度 优选为3～100nm，更优选为10～90nm。在本发明中，所述金属有机配合物优选为无定型结构。 In the present invention, the metal-organic complex is Fe 2+ -2,5-dihydroxyterephthalic acid complex. In the present invention, the Fe 2+ -2,5-dihydroxyterephthalic acid complex means a complex formed by ferrous ions and 2,5-dihydroxyterephthalic acid. In the present invention, the thickness of the shell is preferably 3-100 nm, more preferably 10-90 nm. In the present invention, the metal organic complex preferably has an amorphous structure.
本发明还提供了上述技术方案所述钒酸铋-金属有机配合物复合光电极的制备方法，包括以下步骤：The present invention also provides a method for preparing a bismuth vanadate-metal organic complex composite photoelectrode described in the above technical solution, comprising the following steps:
提供BiVO 4光电极，所述BiVO 4光电极包括基底和负载于所述基底表面的BiVO 4薄膜，所述BiVO 4薄膜由BiVO 4颗粒形成； A BiVO4 photoelectrode is provided, the BiVO4 photoelectrode includes a substrate and a BiVO4 thin film supported on the surface of the substrate, the BiVO4 thin film is formed by BiVO4 particles;
将无机金属盐、有机配体和溶剂混合，得到无机金属盐-配体混合液；所述无机金属盐包括无机亚铁盐；所述有机配体为2,5-二羟基对苯二甲酸；mixing an inorganic metal salt, an organic ligand and a solvent to obtain an inorganic metal salt-ligand mixed liquid; the inorganic metal salt includes an inorganic ferrous salt; the organic ligand is 2,5-dihydroxyterephthalic acid;
将BiVO 4光电极置于无机金属盐-配体混合液浸没，进行水热反应，得到所述钒酸铋-金属有机配合物复合光电极。 The BiVO 4 photoelectrode is immersed in the inorganic metal salt-ligand mixed solution, and the hydrothermal reaction is carried out to obtain the bismuth vanadate-metal organic complex composite photoelectrode.
在本发明中，若无特殊限定，所述制备方法中的各试剂均为本领域技术人员熟知的市售商品。In the present invention, unless otherwise specified, each reagent in the preparation method is a commercially available product well known to those skilled in the art.
本发明提供BiVO 4光电极，所述BiVO 4光电极包括基底和负载于所述基底表面的BiVO 4薄膜，所述BiVO 4薄膜由BiVO 4颗粒形成。 The invention provides a BiVO 4 photoelectrode, the BiVO 4 photoelectrode includes a substrate and a BiVO 4 thin film supported on the surface of the substrate, and the BiVO 4 thin film is formed by BiVO 4 particles.
在本发明中，所述基底优选包括FTO导电玻璃。本发明对所述基底的厚度没有特殊限定，采用本领域技术人员熟知的基底厚度即可。In the present invention, the substrate preferably includes FTO conductive glass. In the present invention, there is no special limitation on the thickness of the substrate, and the thickness of the substrate well known to those skilled in the art can be used.
在本发明中，所述BiVO 4光电极包括负载于所述基底表面的BiVO 4薄膜，所述BiVO 4薄膜由BiVO 4颗粒形成。在本发明中，所述BiVO 4薄膜的厚度优选为500～1000nm，更优选为550～950nm。在本发明中，所述BiVO 4颗粒的粒度优选为100～200nm，更优选为120～180nm。 In the present invention, the BiVO 4 photoelectrode includes a BiVO 4 thin film supported on the surface of the substrate, and the BiVO 4 thin film is formed by BiVO 4 particles. In the present invention, the thickness of the BiVO 4 thin film is preferably 500-1000 nm, more preferably 550-950 nm. In the present invention, the particle size of the BiVO 4 particles is preferably 100-200 nm, more preferably 120-180 nm.
在本发明中，所述BiVO 4光电极的制备方法，优选包括以下步骤： In the present invention, the preparation method of the BiVO photoelectrode preferably comprises the following steps:
将碘化钾水溶液与硝酸铋混合，得到碘化钾-硝酸铋混合液；Mix potassium iodide aqueous solution with bismuth nitrate to obtain potassium iodide-bismuth nitrate mixed solution;
将所述碘化钾-硝酸铋混合液和对苯醌的乙醇溶液混合，得到电解质溶液；Mixing the potassium iodide-bismuth nitrate mixed solution with an ethanol solution of p-benzoquinone to obtain an electrolyte solution;
在所述电解质溶液存在条件下，以基底为工作电极、Ag/AgCl电极为参比电极、铂网为对电极，进行恒电位沉积，得到BiOI光电极；In the presence of the electrolyte solution, the substrate is used as the working electrode, the Ag/AgCl electrode is used as the reference electrode, and the platinum mesh is used as the counter electrode, and constant potential deposition is performed to obtain a BiOI photoelectrode;
将乙酰丙酮钒与二甲基亚砜混合，得到乙酰丙酮钒溶液；Vanadium acetylacetonate is mixed with dimethyl sulfoxide to obtain a vanadium acetylacetonate solution;
将所述乙酰丙酮钒溶液滴涂在所述BiOI电极表面，进行煅烧，得到所述BiVO 4光电极。 The vanadium acetylacetonate solution is drop-coated on the surface of the BiOI electrode and calcined to obtain the BiVO 4 photoelectrode.
本发明将碘化钾水溶液与硝酸铋混合，得到碘化钾-硝酸铋混合液。The invention mixes potassium iodide aqueous solution and bismuth nitrate to obtain potassium iodide-bismuth nitrate mixed liquid.
在本发明中，所述碘化钾水溶液的浓度优选为0.45～0.55mol/L，更优选为0.5mol/L。在本发明中，所述碘化钾水溶液的pH值优选为1.7。In the present invention, the concentration of the potassium iodide aqueous solution is preferably 0.45-0.55 mol/L, more preferably 0.5 mol/L. In the present invention, the pH value of the potassium iodide aqueous solution is preferably 1.7.
在本发明中，对所述碘化钾水溶液的pH值进行调节的试剂优选为浓硝酸，所述浓硝酸的浓度优选为68wt.％。在本发明中，所述碘化钾-硝酸铋混合液中硝酸铋的浓度优选为0.05～0.07mol/L，更优选为0.055～0.065mol/L，最优选为0.06mol/L。在本发明中，所述碘化钾水溶液优选由碘化钾和超纯水配制。In the present invention, the reagent for adjusting the pH value of the potassium iodide aqueous solution is preferably concentrated nitric acid, and the concentration of the concentrated nitric acid is preferably 68wt.%. In the present invention, the concentration of bismuth nitrate in the potassium iodide-bismuth nitrate mixed solution is preferably 0.05-0.07 mol/L, more preferably 0.055-0.065 mol/L, most preferably 0.06 mol/L. In the present invention, the potassium iodide aqueous solution is preferably prepared from potassium iodide and ultrapure water.
在本发明中，所述碘化钾水溶液与硝酸铋的混合优选为超声；本发明对所述超声没有特殊限定，采用本领域技术人员熟知的超声即可。In the present invention, the mixing of the potassium iodide aqueous solution and bismuth nitrate is preferably ultrasonic; the present invention has no special limitation on the ultrasonic, and the ultrasonic well known to those skilled in the art can be used.
得到碘化钾-硝酸铋混合液后，本发明将所述碘化钾-硝酸铋混合液和对苯醌的乙醇溶液混合，得到电解质溶液。After obtaining the potassium iodide-bismuth nitrate mixed solution, the present invention mixes the potassium iodide-bismuth nitrate mixed solution with an ethanol solution of p-benzoquinone to obtain an electrolyte solution.
在本发明中，所述对苯醌的乙醇溶液中对苯醌的浓度优选为0.25～0.35mol/L，更优选为0.28～0.32mol/L，最优选为0.3mol/L。In the present invention, the concentration of p-benzoquinone in the ethanol solution of p-benzoquinone is preferably 0.25-0.35 mol/L, more preferably 0.28-0.32 mol/L, most preferably 0.3 mol/L.
在本发明中，所述碘化钾-硝酸铋混合液和对苯醌溶液的体积比优选为5：(1.8～2.2)，更优选为5：(1.9～2.1)，最优选为5：2。In the present invention, the volume ratio of the potassium iodide-bismuth nitrate mixed solution to the p-benzoquinone solution is preferably 5:(1.8-2.2), more preferably 5:(1.9-2.1), and most preferably 5:2.
得到电解质溶液后，本发明在所述电解质溶液存在条件下，以基底为工作电极、Ag/AgCl电极为参比电极、铂网为对电极，进行恒电位沉积，得到BiOI光电极。After the electrolyte solution is obtained, in the present invention, the substrate is used as the working electrode, the Ag/AgCl electrode is used as the reference electrode, and the platinum mesh is used as the counter electrode under the condition that the electrolyte solution exists, and the constant potential deposition is performed to obtain the BiOI photoelectrode.
本发明对所述Ag/AgCl电极和铂网没有特殊限定，采用本领域技术人员熟知的Ag/AgCl电极和铂网即可。The present invention has no special limitation on the Ag/AgCl electrode and platinum mesh, and the Ag/AgCl electrode and platinum mesh well known to those skilled in the art can be used.
在本发明中，所述恒电位沉积的电位优选为-0.05～-0.2V，更优选为-0.08～-1.5V，最优选为-0.1V；时间优选为3～10min，更优选为4～8min，最优选为5min。In the present invention, the potential of the constant potential deposition is preferably -0.05 ~ -0.2V, more preferably -0.08 ~ -1.5V, most preferably -0.1V; the time is preferably 3 ~ 10min, more preferably 4 ~ 8min, most preferably 5min.
所述恒电位沉积后，本发明优选将所得样品进行清洗，以去除表面杂质；在本发明中，所述清洗用试剂优选包括去离子水。本发明对所述清洗没有特殊限定，采用本领域技术人员熟知的清洗即可。After the potentiostatic deposition, the present invention preferably cleans the obtained sample to remove surface impurities; in the present invention, the cleaning reagent preferably includes deionized water. The present invention has no special limitation on the cleaning, and the cleaning well known to those skilled in the art can be used.
本发明将乙酰丙酮钒与二甲基亚砜混合，得到乙酰丙酮钒溶液。The invention mixes vanadium acetylacetonate and dimethyl sulfoxide to obtain vanadium acetylacetonate solution.
在本发明中，所述乙酰丙酮钒溶液的浓度优选为0.08～0.12mol/L，更优选为0.1mol/L。In the present invention, the concentration of the vanadium acetylacetonate solution is preferably 0.08-0.12 mol/L, more preferably 0.1 mol/L.
得到乙酰丙酮钒溶液和BiOI光电极后，本发明将所述乙酰丙酮钒溶液滴涂在所述BiOI电极表面，进行煅烧，得到所述BiVO 4光电极。 After obtaining the vanadium acetylacetonate solution and the BiOI photoelectrode, the present invention drip-coats the vanadium acetylacetonate solution on the surface of the BiOI electrode, and performs calcination to obtain the BiVO 4 photoelectrode.
在本发明中，所述乙酰丙酮钒溶液在BiOI电极表面的滴涂量优选为100～120μL/cm 2，更优选为105～115μL/cm 2。在本发明中，所述煅烧的温度优选为440～460℃，更优选为445～455℃，最优选为450℃；时间优选为1.5～2.5h，更优选为1.8～2.3h，最优选为2h。在本发明中，所述煅烧优选在马弗炉中进行。在本发明中，所述煅烧过程中，BiOI分解为Bi 2O 3，乙酰丙酮氧钒分解为V 2O 5，所述Bi 2O 3与V 2O 5发生高温固相反应生成BiVO 4。 In the present invention, the dispensing amount of the vanadium acetylacetonate solution on the surface of the BiOI electrode is preferably 100-120 μL/cm 2 , more preferably 105-115 μL/cm 2 . In the present invention, the temperature of the calcination is preferably 440-460°C, more preferably 445-455°C, most preferably 450°C; the time is preferably 1.5-2.5h, more preferably 1.8-2.3h, most preferably 2h. In the present invention, the calcination is preferably performed in a muffle furnace. In the present invention, during the calcination process, BiOI is decomposed into Bi 2 O 3 , vanadyl acetylacetonate is decomposed into V 2 O 5 , and the Bi 2 O 3 and V 2 O 5 undergo a high-temperature solid-state reaction to generate BiVO 4 .
在本发明中，所述煅烧后优选还包括洗涤，具体的，所述洗涤优选为将煅烧所得样品置于氢氧化钠溶液中浸泡，以去除残余的V 2O 5，得到BiVO 4光电极。在本发明中，所述氢氧化钠溶液的浓度优选为1mol/L。在本发明中，所述浸泡的温度优选为18～25℃，时间优选为30min。 In the present invention, washing is preferably included after the calcination. Specifically, the washing is preferably soaking the calcined sample in a sodium hydroxide solution to remove residual V 2 O 5 to obtain a BiVO 4 photoelectrode. In the present invention, the concentration of the sodium hydroxide solution is preferably 1 mol/L. In the present invention, the soaking temperature is preferably 18-25° C., and the soaking time is preferably 30 minutes.
本发明将无机金属盐、有机配体和溶剂混合，得到无机金属盐-配体混合液。The invention mixes the inorganic metal salt, the organic ligand and the solvent to obtain the inorganic metal salt-ligand mixed liquid.
在本发明中，所述无机金属盐包括无机亚铁盐。在本发明中，所述无机亚铁盐优选包括氯化亚铁、硫酸亚铁或硝酸亚铁。在本发明中，所述有机配体为2,5-二羟基对苯二甲酸。In the present invention, the inorganic metal salt includes inorganic ferrous salt. In the present invention, the inorganic ferrous salt preferably includes ferrous chloride, ferrous sulfate or ferrous nitrate. In the present invention, the organic ligand is 2,5-dihydroxyterephthalic acid.
在本发明中，所述无机金属盐-配体混合液中无机金属金属离子和有机配体的摩尔比优选为1：(2～3)，更优选为1：(2.2～2.8)。In the present invention, the molar ratio of the inorganic metal metal ion and the organic ligand in the inorganic metal salt-ligand mixed liquid is preferably 1:(2-3), more preferably 1:(2.2-2.8).
在本发明中，所述溶剂优选为乙醇、水和N,N-二甲基甲酰胺(DMF)。在本发明中，所述溶剂中乙醇、水和N,N-二甲基甲酰胺的体积比优选为1：1：(10～20)。In the present invention, the solvent is preferably ethanol, water and N,N-dimethylformamide (DMF). In the present invention, the volume ratio of ethanol, water and N,N-dimethylformamide in the solvent is preferably 1:1:(10-20).
在本发明中，所述无机金属盐-配体混合液中无机金属盐的浓度优选为8～50mmol/L，更优选为8.2～30mmol/L。In the present invention, the concentration of the inorganic metal salt in the inorganic metal salt-ligand mixed solution is preferably 8-50 mmol/L, more preferably 8.2-30 mmol/L.
得到BiVO 4光电极和无机金属盐-配体混合液后，本发明将BiVO 4光电极置于无机金属盐-配体混合液浸没，进行水热反应，得到所述钒酸铋-金属有机配合物复合光电极。 After obtaining the BiVO 4 photoelectrode and the inorganic metal salt-ligand mixed solution, the present invention immerses the BiVO 4 photoelectrode in the inorganic metal salt-ligand mixed solution, and performs a hydrothermal reaction to obtain the bismuth vanadate-organic metal complex composite photoelectrode.
在本发明中，所述水热反应的温度优选为130～150℃，更优选为135～145℃；时间优选为10～16h，更优选为11～15h。在本发明中，所述 水热反应优选在不锈钢高压反应釜中进行。在本发明中，亚铁离子与2,5-二羟基对苯二甲酸配体发生自组装反应，生成无定型结构的金属有机络合物。In the present invention, the temperature of the hydrothermal reaction is preferably 130-150° C., more preferably 135-145° C.; the time is preferably 10-16 hours, more preferably 11-15 hours. In the present invention, the hydrothermal reaction is preferably carried out in a stainless steel autoclave. In the present invention, ferrous ions undergo self-assembly reaction with 2,5-dihydroxy terephthalic acid ligands to generate metal-organic complexes with amorphous structure.
所述水热反应后，本发明优选还包括：将水热反应所得产物依次进行清洗和干燥，得到所述钒酸铋-金属有机配合物复合光电极。在本发明中，所述清洗优选包括交替进行的乙醇洗和水洗。在本发明中，所述干燥的温度优选为40～65℃，更优选为45～60℃；时间优选为5～30min，更优选为10～25min。在本发明中，所述干燥的设备优选为烘箱。After the hydrothermal reaction, the present invention preferably further includes: sequentially washing and drying the product obtained from the hydrothermal reaction to obtain the bismuth vanadate-metal organic complex composite photoelectrode. In the present invention, the cleaning preferably includes washing with ethanol and washing with water alternately. In the present invention, the drying temperature is preferably 40-65° C., more preferably 45-60° C.; the drying time is preferably 5-30 minutes, more preferably 10-25 minutes. In the present invention, the drying equipment is preferably an oven.
本发明还提供了上述技术方案所述钒酸铋-金属有机配合物复合光电极或上述技术方案所述制备方法得到的钒酸铋-金属有机配合物复合光电极作为催化电极在光电催化水氧化反应中的应用。The present invention also provides the bismuth vanadate-metal organic complex composite photoelectrode described in the above technical scheme or the bismuth vanadate-metal organic complex composite photoelectrode obtained by the preparation method described in the above technical scheme as a catalytic electrode in photoelectric catalytic water oxidation React application.
本发明对所述应用没有特殊限定，采用本领域技术人员熟知的催化电极在光电催化水氧化反应中的应用即可。The present invention has no special limitation on the application, and the application of the catalytic electrode well-known to those skilled in the art in the photoelectrocatalytic water oxidation reaction can be used.
为了进一步说明本发明，下面结合实施例对本发明提供的一种钒酸铋-金属有机配合物复合光电极及其制备方法和应用进行详细地描述，但不能将它们理解为对本发明保护范围的限定。显然，所描述的实施例仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。In order to further illustrate the present invention, a bismuth vanadate-metal organic complex composite photoelectrode provided by the present invention and its preparation method and application are described in detail below in conjunction with the examples, but they cannot be interpreted as limiting the protection scope of the present invention . Apparently, the described embodiments are only some of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.
实施例1Example 1
将碘化钾和超纯水混合，利用浓度为68wt％的浓硝酸调节pH值至1.7，得到浓度为0.5mol/L的碘化钾水溶液；将硝酸铋与所述碘化钾水溶液混合，超声溶解，得到硝酸铋的浓度为0.06mol/L的碘化钾-硝酸铋混合液；Potassium iodide and ultrapure water were mixed, and the concentrated nitric acid with a concentration of 68wt% was used to adjust the pH value to 1.7 to obtain a potassium iodide aqueous solution with a concentration of 0.5mol/L; bismuth nitrate was mixed with the potassium iodide aqueous solution, and ultrasonically dissolved to obtain bismuth nitrate Concentration is the potassium iodide-bismuth nitrate mixed solution of 0.06mol/L;
将对苯醌与乙醇混合，超声溶解，得到对苯醌浓度为0.3mol/L的对苯醌的乙醇溶液；P-benzoquinone is mixed with ethanol, and ultrasonically dissolved to obtain an ethanol solution of p-benzoquinone with a p-benzoquinone concentration of 0.3mol/L;
将所述碘化钾-硝酸铋混合液和对苯醌的乙醇溶液以5：2的体积比混合，搅拌均匀，得到电解质溶液；在所述电解质溶液存在条件下，以FTO导电玻璃为工作电极、Ag/AgCl电极为参比电极、铂网为对电极，在-0.1V电位条件下电沉积5min，沉积结束后利用去离子水清洗去除表面杂质， 得到BiOI光电极；Mix the potassium iodide-bismuth nitrate mixed solution and the ethanol solution of p-benzoquinone at a volume ratio of 5:2, and stir evenly to obtain an electrolyte solution; in the presence of the electrolyte solution, use FTO conductive glass as the working electrode, Ag The /AgCl electrode is used as the reference electrode, and the platinum mesh is used as the counter electrode. Electrodeposition is performed at a potential of -0.1V for 5 minutes. After the deposition is completed, the surface impurities are cleaned with deionized water to obtain a BiOI photoelectrode;
将乙酰丙酮钒与二甲基亚砜混合，得到浓度为0.1mol/L的乙酰丙酮钒溶液，用移液枪移取100μL所述乙酰丙酮钒溶液滴涂在所述BiOI电极表面(乙酰丙酮钒溶液在BiOI电极表面的滴涂量为100μL/cm 2)，之后置于马弗炉中，在450℃下煅烧2h，自然冷却至室温后取出所得产物，置于1mol/L的氢氧化钠溶液中，在室温(25℃)条件下浸泡30min，以去除残余的V 2O 5，得到BiVO 4光电极； Vanadium acetylacetonate was mixed with dimethyl sulfoxide to obtain a vanadium acetylacetonate solution with a concentration of 0.1mol/L, and 100 μL of the vanadium acetylacetonate solution was pipetted onto the surface of the BiOI electrode (vanadium acetylacetonate The drop coating amount of the solution on the surface of the BiOI electrode is 100 μL/cm 2 ), and then placed in a muffle furnace, calcined at 450°C for 2 hours, cooled to room temperature naturally, and the obtained product was taken out, and placed in a 1mol/L sodium hydroxide solution , soaked at room temperature (25°C) for 30 minutes to remove residual V 2 O 5 and obtain a BiVO 4 photoelectrode;
将硫酸亚铁、配体2,5-二羟基对苯二甲酸和溶剂混合，其中，溶剂为乙醇、水和N,N-二甲基甲酰胺的混合溶液，乙醇、水和N,N-二甲基甲酰胺的体积比为1：1：16，得到无机亚铁盐-配体混合液，所述无机亚铁盐-配体混合液中无机亚铁盐的浓度为10.42mmol/L，配体的浓度为20.84mmol/L；Mix ferrous sulfate, ligand 2,5-dihydroxyterephthalic acid and a solvent, wherein the solvent is a mixed solution of ethanol, water and N,N-dimethylformamide, ethanol, water and N,N- The volume ratio of dimethylformamide is 1:1:16, obtains the inorganic ferrous salt-ligand mixed solution, the concentration of inorganic ferrous salt in the described inorganic ferrous salt-ligand mixed solution is 10.42mmol/L, The concentration of the ligand is 20.84mmol/L;
将所得的BiVO 4光电极置于不锈钢高压反应釜内，导电面朝下斜靠在不锈钢高压反应釜内衬中，并于不锈钢高压反应釜内衬中加入无机亚铁盐-配体溶液至浸没BiVO 4光电极，在120℃下进行水热反应12h，反应结束后取出所得水热反应产物，以乙醇和去离子水各冲洗3次，于60℃干燥30min，得到所述钒酸铋-金属有机配合物复合光电极。 The obtained BiVO 4 photoelectrode was placed in a stainless steel autoclave, and the conductive surface leaned against the inner lining of the stainless steel autoclave, and the inorganic ferrous salt-ligand solution was added to the inner lining of the stainless steel autoclave until it was submerged. The BiVO 4 photoelectrode was subjected to a hydrothermal reaction at 120°C for 12 hours. After the reaction, the obtained hydrothermal reaction product was taken out, rinsed three times with ethanol and deionized water, and dried at 60°C for 30 minutes to obtain the bismuth vanadate-metal Organic complex compound photoelectrode.
对实施例1中的BiVO 4光电极和钒酸铋-金属有机配合物复合光电极进行X射线衍射测试，所得XRD图见图1。由图1可见，通过晶体检索软件可知，28.9°、30.5°、34.5°、35.1°、40.2°和42.4°的衍射峰对应于单斜钒酸铋，PDF卡片号为14-0688；剩余的衍射峰可以很好的对应于SnO 2；此外，未发现其他物质的衍射峰，说明制备的钒酸铋为纯相；钒酸铋-金属有机配合物复合光电极衍射峰位置与单纯的BiVO 4一致，未出现其他物质的衍射峰，说明负载的Fe基金属有机络合物要么为无定型，要么负载量较低 The BiVO 4 photoelectrode and the bismuth vanadate-metal-organic complex composite photoelectrode in Example 1 were tested by X-ray diffraction, and the obtained XRD pattern is shown in FIG. 1 . It can be seen from Figure 1 that the diffraction peaks at 28.9°, 30.5°, 34.5°, 35.1°, 40.2° and 42.4° correspond to bismuth monoclinic vanadate, and the PDF card number is 14-0688; the remaining diffraction peaks are The peak can well correspond to SnO 2 ; in addition, no diffraction peaks of other substances are found, indicating that the prepared bismuth vanadate is a pure phase; the position of the diffraction peak of the bismuth vanadate-metal organic complex composite photoelectrode is consistent with that of pure BiVO 4 , no diffraction peaks of other substances appeared, indicating that the supported Fe-based metal-organic complexes were either amorphous or had a low loading
为了进一步确认负载的金属有机络合物的结晶性，采用离心分离、乙醇和水清洗，获得了水热反应釜中的金属有机络合物，采用X射线衍射仪测定所得金属有机络合物的结晶性，所得XRD图见图2。由图2可知，金属有机络合物的XRD图上呈现一个非常宽的衍射峰，说明单纯的金属有机络合物为无定型结构。In order to further confirm the crystallinity of the loaded metal-organic complex, the metal-organic complex in the hydrothermal reaction kettle was obtained by centrifugation, ethanol and water washing, and the obtained metal-organic complex was measured by X-ray diffractometer. Crystallinity, the obtained XRD pattern is shown in Figure 2. It can be seen from Fig. 2 that a very broad diffraction peak appears on the XRD pattern of the metal-organic complex, indicating that the pure metal-organic complex has an amorphous structure.
采用X射线光电子能谱测试实施例1中BiVO 4光电极和所得钒酸铋-金属有机配合物复合光电极，所得XPS图见图3～图4，图3为实施例1中钒酸铋-金属有机配合物复合光电极的Fe2p元素的XPS图，图4为实施例1中BiVO 4光电极和钒酸铋-金属有机配合物复合光电极的C1s元素的XPS图。由图3可见，724eV和711eV结合能处出现两个峰，分别对应于Fe 2p1/2和Fe 2p3/2信号，这两个峰可以很好地反褶积为Fe 3+和Fe 2+，证实了Fe元素的存在；另外，由图4可见，C1s分谱有两个新的特征峰，结合能分别为288.8eV和286.6eV，这个信号来自于配体的C＝O和C-O基团。 Adopt X-ray photoelectron spectroscopy to test BiVO in embodiment 1 Photoelectrode and gained bismuth vanadate-metal organic complex compound photoelectrode, gained XPS figure is shown in Fig. 3～Fig. 4, and Fig. 3 is bismuth vanadate- The XPS diagram of the Fe2p element of the metal organic complex composite photoelectrode, FIG. 4 is the XPS diagram of the C1s element of the BiVO 4 photoelectrode and the bismuth vanadate-metal organic complex composite photoelectrode in Example 1. It can be seen from Figure 3 that two peaks appear at the binding energy of 724eV and 711eV, corresponding to Fe 2p1/2 and Fe 2p3/2 signals respectively, and these two peaks can be well deconvoluted into Fe 3+ and Fe 2+ , The existence of Fe element was confirmed; in addition, as can be seen from Figure 4, there are two new characteristic peaks in the C1s spectrum, the binding energies are 288.8eV and 286.6eV respectively, and this signal comes from the C=O and CO groups of the ligand.
采用红外光谱测试BiVO 4光电极和钒酸铋-金属有机配合物复合光电极，所得IR图见图5。由图5可知，钒酸铋-金属有机配合物复合光电极在波数为1556、1415、1240、1200、1112、1031、560、514cm -1处产生了一些新峰，其中，1556cm -1处的峰可以归属于羧基基团的非对称伸缩振动，500-800cm -1处的系列峰来源于苯环的振动，1112cm -1处的峰来源于C-OH振动；结合所有这些表征，可以很好的证实金属有机络合物的存在。 The BiVO 4 photoelectrode and bismuth vanadate-metal-organic complex composite photoelectrode were tested by infrared spectroscopy, and the obtained IR diagram is shown in Figure 5. It can be seen from Figure 5 that the bismuth vanadate-metal organic complex composite photoelectrode has some new peaks at the wavenumbers of 1556, 1415, 1240, 1200, 1112, 1031, 560, and 514cm -1 , among which the peak at 1556cm -1 The peaks can be attributed to the asymmetric stretching vibrations of the carboxyl group, the series of peaks at 500-800 cm -1 originate from the vibrations of the benzene ring, and the peak at 1112 cm -1 originates from the C-OH vibrations; combining all these characterizations, it can be well The confirmation of the presence of metal-organic complexes.
对BiVO 4光电极和钒酸铋-金属有机配合物复合光电极在不同电极电位下表面载流子复合速率常数进行测试，测试结果见图6。由图6可见，本发明提供的钒酸铋-金属有机配合物复合光电极在不同电极电位下表面载流子复合速率常数更低，说明本发明提供的钒酸铋-金属有机配合物复合光电极可以显著提高复合光电极和电解质界面的光生空穴浓度，有利于加速界面水氧化速率。 The surface carrier recombination rate constants of the BiVO 4 photoelectrode and the bismuth vanadate-metal organic complex composite photoelectrode were tested at different electrode potentials, and the test results are shown in Figure 6. As can be seen from Figure 6, the bismuth vanadate-metal organic complex composite photoelectrode provided by the invention has lower surface carrier recombination rate constants at different electrode potentials, indicating that the bismuth vanadate-metal organic complex composite photoelectrode provided by the invention The electrode can significantly increase the concentration of photogenerated holes at the interface between the composite photoelectrode and the electrolyte, which is beneficial to accelerate the rate of interfacial water oxidation.
实施例2Example 2
按照实施例1的方法制备得到BiVO 4光电极； According to the method of embodiment 1, BiVO4 photoelectrode is prepared;
将氯化亚铁、配体2,5-二羟基对苯二甲酸和溶剂混合，其中，溶剂为乙醇、水和N,N-二甲基甲酰胺的混合溶液，乙醇、水和N,N-二甲基甲酰胺的体积比为1：1：20，得到无机亚铁盐-配体混合液，所述无机亚铁盐-配体混合液中氯化亚铁的浓度为10.42mmol/L，配体的浓度为22.22mmol/L；Mix ferrous chloride, ligand 2,5-dihydroxyterephthalic acid and a solvent, wherein the solvent is a mixed solution of ethanol, water and N,N-dimethylformamide, ethanol, water and N,N -The volume ratio of dimethylformamide is 1:1:20 to obtain the inorganic ferrous salt-ligand mixed solution, the concentration of ferrous chloride in the inorganic ferrous salt-ligand mixed solution is 10.42mmol/L , the concentration of the ligand is 22.22mmol/L;
将所得的BiVO 4光电极置于不锈钢高压反应釜内，导电面朝下斜靠在不锈钢高压反应釜内衬中，并于不锈钢高压反应釜内衬中加入无机亚铁 盐-配体溶液至浸没BiVO 4光电极，在120℃下进行水热反应8h，反应结束后取出所得水热反应产物，以乙醇和去离子水各冲洗3次，于60℃干燥30min，得到所述钒酸铋-金属有机配合物复合光电极。 The obtained BiVO 4 photoelectrode was placed in a stainless steel autoclave, and the conductive surface leaned against the inner lining of the stainless steel autoclave, and the inorganic ferrous salt-ligand solution was added to the inner lining of the stainless steel autoclave until it was submerged. The BiVO 4 photoelectrode was subjected to a hydrothermal reaction at 120°C for 8 hours. After the reaction, the obtained hydrothermal reaction product was taken out, rinsed three times with ethanol and deionized water, and dried at 60°C for 30 minutes to obtain the bismuth vanadate-metal Organic complex compound photoelectrode.
对实施例2中的BiVO 4光电极和钒酸铋-金属有机配合物复合光电极进行扫描电子显微测试，所得SEM图见图7，图7中(A)为BiVO 4光电极，(B)为钒酸铋-金属有机配合物复合光电极。由图7的(A)可见，BiVO 4为纳米颗粒，表面较光滑；由图7的(B)可见，金属有机配合物均匀负载在BiVO 4颗粒表面，形成稳定的核壳结构，说明2,5-二羟基对苯二甲酸可以作为偶联剂将金属有机配合物牢牢黏附在BiVO 4颗粒表面，其中，所述BiVO 4纳米颗粒的粒度为100～200nm，壳层厚度为3～100nm。 The BiVO photoelectrode and the bismuth vanadate-metal-organic complex composite photoelectrode in Example 2 are subjected to scanning electron microscopy, and the resulting SEM figure is shown in Fig. 7, ( A) in Fig. 7 is the BiVO photoelectrode, (B ) is a bismuth vanadate-metal organic complex composite photoelectrode. It can be seen from (A) of Figure 7 that BiVO 4 is a nanoparticle with a smooth surface; it can be seen from (B) of Figure 7 that the metal-organic complexes are evenly loaded on the surface of BiVO 4 particles, forming a stable core-shell structure, indicating 2, 5-dihydroxyterephthalic acid can be used as a coupling agent to firmly adhere metal-organic complexes to the surface of BiVO 4 particles, wherein the BiVO 4 nanoparticles have a particle size of 100-200 nm and a shell thickness of 3-100 nm.
对BiVO 4光电极和钒酸铋-金属有机配合物复合光电极在暗态和光照条件下进行线性扫描伏安测试，所得光开-光关条件下的线性扫描伏安曲线图见图8。由图8可见，暗态下BiVO 4光电极和钒酸铋-金属有机配合物复合光电极的电流很低，说明暗态下无法实现水分解；光照后，电流明显提升，且电流均随电位的增加而增加。但是，相比而言，钒酸铋-金属有机配合物复合光电极较无修饰的BiVO 4光电极的光电流有显著提升，例如，0.4V(vs.Ag/AgCl)偏压下，钒酸铋-金属有机配合物复合光电极的电流密度达到了1.38mA·cm -2，是BiVO 4光电极的4.6倍。这个结果表明，本发明提供的钒酸铋-金属有机配合物复合光电极在负载金属有机络合物后，BiVO 4光电极的界面传荷阻值明显减少，导致水氧化反应速率明显提升，进而有效改善了水氧化活性。 The linear sweep voltammetry test was carried out on the BiVO 4 photoelectrode and the bismuth vanadate-metal organic complex composite photoelectrode under dark and light conditions, and the obtained linear sweep voltammetry curves under light-on-light-off conditions are shown in Figure 8. It can be seen from Figure 8 that the currents of the BiVO 4 photoelectrode and bismuth vanadate-metal-organic complex composite photoelectrode in the dark state are very low, indicating that water splitting cannot be achieved in the dark state; increased by the increase. However, in comparison, the photocurrent of bismuth vanadate-metal-organic complex composite photoelectrode is significantly improved compared with the unmodified BiVO 4 photoelectrode, for example, at 0.4V (vs.Ag/AgCl) bias, The current density of bismuth-metal-organic complex composite photoelectrode reaches 1.38mA·cm -2 , which is 4.6 times that of BiVO 4 photoelectrode. This result shows that, after the bismuth vanadate-metal organic complex composite photoelectrode provided by the present invention is loaded with the metal organic complex, the interfacial load transfer resistance of the BiVO4 photoelectrode is significantly reduced, resulting in a significant increase in the water oxidation reaction rate, and further Effectively improved water oxidation activity.
实施例3Example 3
按照实施例1的方法制备得到BiVO 4光电极； According to the method of embodiment 1, BiVO4 photoelectrode is prepared;
将硝酸亚铁、配体2,5-二羟基对苯二甲酸和溶剂混合，其中，溶剂为乙醇、水和N,N-二甲基甲酰胺的混合溶液，乙醇、水和N,N-二甲基甲酰胺的体积比为1：1：16，得到无机亚铁盐-配体混合液，所述无机亚铁盐-配体混合液中无机亚铁盐的浓度为8.33mmol/L，配体的浓度为22.22mmol/L；Mix ferrous nitrate, ligand 2,5-dihydroxyterephthalic acid and a solvent, wherein the solvent is a mixed solution of ethanol, water and N,N-dimethylformamide, ethanol, water and N,N- The volume ratio of dimethylformamide is 1:1:16, obtains the inorganic ferrous salt-ligand mixed solution, the concentration of inorganic ferrous salt in the described inorganic ferrous salt-ligand mixed solution is 8.33mmol/L, The concentration of ligand is 22.22mmol/L;
将所得的BiVO 4光电极置于不锈钢高压反应釜内，导电面朝下斜靠在不锈钢高压反应釜内衬中，并于不锈钢高压反应釜内衬中加入无机亚铁 盐-配体溶液至浸没BiVO 4光电极，在120℃下进行水热反应12h，反应结束后取出所得水热反应产物，以乙醇和去离子水各冲洗3次，于60℃干燥30min，得到所述钒酸铋-金属有机配合物复合光电极。 The obtained BiVO 4 photoelectrode was placed in a stainless steel autoclave, and the conductive surface leaned against the inner lining of the stainless steel autoclave, and the inorganic ferrous salt-ligand solution was added to the inner lining of the stainless steel autoclave until it was submerged. The BiVO 4 photoelectrode was subjected to a hydrothermal reaction at 120°C for 12 hours. After the reaction, the obtained hydrothermal reaction product was taken out, rinsed three times with ethanol and deionized water, and dried at 60°C for 30 minutes to obtain the bismuth vanadate-metal Organic complex compound photoelectrode.
测试实施例3所得BiVO 4光电极和钒酸铋-金属有机配合物复合光电极在0.4V(vs.Ag/AgCl)外加偏压下的电流-时间关系，测试电解质溶液为0.1mol/L的KHCO 3溶液，电解质溶液pH值为9，所得电流-时间曲线图见图9。由图9可知，BiVO 4光电极的电流密度随时间逐渐减小；3h后，BiVO 4光电极的电流密度由初始时的0.26mA·cm -2减小到0.12mA·cm -2，说明单纯的BiVO 4光电极稳定性不好。钒酸铋-金属有机配合物复合光电极的电流密度较钒酸铋高，且钒酸铋-金属有机配合物复合光电极的电流密度随时间的变化较小，3h后电流密度几乎无衰减，说明金属有机配合物的均匀负载有效提升了钒酸铋电极的稳定性和活性，说明了钒酸铋-金属有机配合物复合光电极在光电催化水分解领域具有巨大的应用潜力。 Test the obtained BiVO4 photoelectrode of Example 3 and the bismuth vanadate-metal organic complex composite photoelectrode under the current-time relationship under the bias voltage of 0.4V (vs.Ag/AgCl), the test electrolyte solution is 0.1mol/L KHCO 3 solution, the pH value of the electrolyte solution is 9, and the obtained current-time curve is shown in Figure 9. It can be seen from Figure 9 that the current density of the BiVO 4 photoelectrode decreases gradually with time; after 3 hours, the current density of the BiVO 4 photoelectrode decreases from the initial 0.26mA·cm -2 to 0.12mA·cm -2 , indicating that the simple The BiVO 4 photoelectrode is not stable. The current density of the bismuth vanadate-metal organic complex composite photoelectrode is higher than that of bismuth vanadate, and the current density of the bismuth vanadate-metal organic complex composite photoelectrode changes less with time, and the current density has almost no decay after 3 hours. It shows that the uniform loading of metal-organic complexes can effectively improve the stability and activity of bismuth vanadate electrodes, which shows that bismuth vanadate-metal-organic complex composite photoelectrodes have great application potential in the field of photocatalytic water splitting.
对比例1Comparative example 1
无机亚铁盐-配体混合液中氯化亚铁的浓度为44.44mol/L，配体的浓度为22.22mol/L，其余技术手段与实施例2一致，得到复合光电极，其中，复合光电极中的金属有机配合物为结晶型。The concentration of ferrous chloride in the inorganic ferrous salt-ligand mixed solution is 44.44mol/L, and the concentration of the ligand is 22.22mol/L, all the other technical means are consistent with embodiment 2, obtain composite photoelectrode, wherein, composite photoelectric The metal-organic complexes in the pole are crystalline.
对比例2Comparative example 2
无机亚铁盐-配体混合液中氯化亚铁的浓度为66.66mol/L，配体的浓度为22.22mol/L，其余技术手段与实施例2一致，得到复合光电极，其中，复合光电极中的金属有机配合物为结晶型。The concentration of ferrous chloride in the inorganic ferrous salt-ligand mixed solution is 66.66mol/L, and the concentration of the ligand is 22.22mol/L. The rest of the technical means are consistent with Example 2 to obtain a composite photoelectrode, wherein the composite photoelectric The metal-organic complexes in the pole are crystalline.
对对比例1～2所得复合光电极和BiVO 4光电极进行线性扫描伏安测试，所得线性扫描伏安曲线图见图10。由图10可见，结晶型的金属有机配合物对钒酸铋的水分解性能有抑制作用；进一步分析可知，在本发明中，有机配体浓度增加时，得到无定型结构的金属有机配合物，能够更好地提高钒酸铋基钒酸铋-金属有机配合物复合光电极的水分解性能。 The linear sweep voltammetry test was carried out on the composite photoelectrode and the BiVO 4 photoelectrode obtained in Comparative Examples 1-2, and the obtained linear sweep voltammetry curve is shown in FIG. 10 . As can be seen from Figure 10, the metal-organic complexes of crystalline form have an inhibitory effect on the water-splitting performance of bismuth vanadate; further analysis shows that in the present invention, when the concentration of organic ligands increases, the metal-organic complexes of amorphous structure are obtained, The water splitting performance of the bismuth vanadate-based bismuth vanadate-metal organic complex compound photoelectrode can be better improved.
以上实施例的说明只是用于帮助理解本发明的方法及其核心思想。应当指出，对于本技术领域的普通技术人员来说，在不脱离本发明原理的前提下，还可以对本发明进行若干改进和修饰，这些改进和修饰也落入本发明权利要求的保护范围内。对这些实施例的多种修改对本领域的专业技术 人员来说是显而易见的，本文中所定义的一般原理可以在不脱离本发明的精神或范围的情况下在其它实施例中实现。因此，本发明将不会被限制于本文所示的这些实施例，而是要符合与本文所公开的原理和新颖特点相一致的最宽的范围。The descriptions of the above embodiments are only used to help understand the method and core idea of the present invention. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, some improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (14)

  1. 一种钒酸铋-金属有机配合物复合光电极，包括基底和负载在所述基底表面的BiVO 4-金属有机配合物复合薄膜，所述BiVO 4-金属有机配合物复合薄膜由BiVO 4-金属有机配合物颗粒构成；所述BiVO 4-金属有机配合物包括BiVO 4内核和包覆所述BiVO 4内核的金属有机配合物形成的外壳； A bismuth vanadate-metal organic complex composite photoelectrode, comprising a substrate and a BiVO 4 -metal organic complex composite film loaded on the surface of the substrate, the BiVO 4 -metal organic complex composite film is composed of BiVO 4 -metal Organic complex particle composition; the BiVO 4 -metal organic complex includes a BiVO inner core and a shell formed by a metal organic complex covering the BiVO inner core ;
    所述金属有机配合物为Fe 2+-2,5-二羟基对苯二甲酸络合物。 The metal-organic complex is Fe 2+ -2,5-dihydroxyterephthalic acid complex.
  2. 根据权利要求1所述的钒酸铋-金属有机配合物复合光电极，其特征在于，所述金属有机配合物为无定型结构。The bismuth vanadate-metal organic complex composite photoelectrode according to claim 1, characterized in that the metal organic complex has an amorphous structure.
  3. 根据权利要求1所述的钒酸铋-金属有机配合物复合光电极，其特征在于，所述BiVO 4内核的粒径为100～200nm；所述外壳的厚度为3～100nm。 The bismuth vanadate-metal organic complex composite photoelectrode according to claim 1, characterized in that, the particle diameter of the BiVO 4 inner core is 100-200 nm; the thickness of the outer shell is 3-100 nm.
  4. 根据权利要求1所述的钒酸铋-金属有机配合物复合光电极，其特征在于，所述BiVO 4-金属有机配合物复合薄膜的厚度为1～50μm。 The bismuth vanadate-metal organic complex composite photoelectrode according to claim 1, characterized in that the thickness of the BiVO 4 -metal organic complex composite thin film is 1-50 μm.
  5. 权利要求1～4任一项所述钒酸铋-金属有机配合物复合光电极的制备方法，包括以下步骤：The preparation method of the bismuth vanadate-metal organic complex composite photoelectrode described in any one of claims 1 to 4, comprising the following steps:
    提供BiVO 4光电极，所述BiVO 4光电极包括基底和负载于所述基底表面的BiVO 4薄膜，所述BiVO 4薄膜由BiVO 4颗粒形成； A BiVO4 photoelectrode is provided, the BiVO4 photoelectrode includes a substrate and a BiVO4 thin film supported on the surface of the substrate, the BiVO4 thin film is formed by BiVO4 particles;
    将无机金属盐、有机配体和溶剂混合，得到无机金属盐-配体混合液；所述无机金属盐包括无机亚铁盐；所述有机配体为2,5-二羟基对苯二甲酸；mixing an inorganic metal salt, an organic ligand and a solvent to obtain an inorganic metal salt-ligand mixed liquid; the inorganic metal salt includes an inorganic ferrous salt; the organic ligand is 2,5-dihydroxyterephthalic acid;
    将BiVO 4光电极置于无机金属盐-配体混合液浸没，进行水热反应，得到所述钒酸铋-金属有机配合物复合光电极。 The BiVO 4 photoelectrode is immersed in the inorganic metal salt-ligand mixed solution, and the hydrothermal reaction is carried out to obtain the bismuth vanadate-metal organic complex composite photoelectrode.
  6. 根据权利要求5所述的制备方法，其特征在于，所述BiVO 4薄膜的厚度为500～1000nm。 The preparation method according to claim 5, characterized in that, the thickness of the BiVO4 thin film is 500-1000 nm.
  7. 根据权利要求5或6所述的制备方法，其特征在于，所述BiVO 4颗粒的粒度为100～200nm。 The preparation method according to claim 5 or 6, characterized in that the particle size of the BiVO 4 particles is 100-200 nm.
  8. 根据权利要求5所述的制备方法，其特征在于，所述BiVO 4光电极的制备方法，包括以下步骤： preparation method according to claim 5, is characterized in that, the preparation method of described BiVO photoelectrode , comprises the following steps:
    将碘化钾水溶液与硝酸铋混合，得到碘化钾-硝酸铋混合液；Mix potassium iodide aqueous solution with bismuth nitrate to obtain potassium iodide-bismuth nitrate mixed solution;
    将所述碘化钾-硝酸铋混合液和对苯醌的乙醇溶液混合，得到电解质溶液；Mixing the potassium iodide-bismuth nitrate mixed solution with an ethanol solution of p-benzoquinone to obtain an electrolyte solution;
    在所述电解质溶液存在条件下，以基底为工作电极、Ag/AgCl电极为参比电极、铂网为对电极，进行恒电位沉积，得到BiOI光电极；In the presence of the electrolyte solution, the substrate is used as the working electrode, the Ag/AgCl electrode is used as the reference electrode, and the platinum mesh is used as the counter electrode, and constant potential deposition is performed to obtain a BiOI photoelectrode;
    将乙酰丙酮钒与二甲基亚砜混合，得到乙酰丙酮钒溶液；Vanadium acetylacetonate is mixed with dimethyl sulfoxide to obtain a vanadium acetylacetonate solution;
    将所述乙酰丙酮钒溶液滴涂在所述BiOI电极表面，进行煅烧，得到所述BiVO 4光电极。 The vanadium acetylacetonate solution is drop-coated on the surface of the BiOI electrode and calcined to obtain the BiVO 4 photoelectrode.
  9. 根据权利要求5所述的制备方法，其特征在于，所述无机亚铁盐包括氯化亚铁、硫酸亚铁或硝酸亚铁。The preparation method according to claim 5, wherein the inorganic ferrous salt comprises ferrous chloride, ferrous sulfate or ferrous nitrate.
  10. 根据权利要求5所述的制备方法，其特征在于，所述无机金属盐-配体混合液中无机金属离子和有机配体的摩尔比为1：(2～3)。The preparation method according to claim 5, characterized in that the molar ratio of inorganic metal ions and organic ligands in the inorganic metal salt-ligand mixed solution is 1:(2-3).
  11. 根据权利要求5所述的制备方法，其特征在于，所述溶剂为乙醇、水和N,N-二甲基甲酰胺；所述溶剂中乙醇、水和N,N-二甲基甲酰胺的体积比为1：1：(10～20)。The preparation method according to claim 5, characterized in that, the solvent is ethanol, water and N,N-dimethylformamide; the content of ethanol, water and N,N-dimethylformamide in the solvent The volume ratio is 1:1:(10~20).
  12. 根据权利要求5或11所述的制备方法，其特征在于，所述无机金属盐-配体混合液中无机金属盐的浓度为8～50mmol/L。The preparation method according to claim 5 or 11, characterized in that the concentration of the inorganic metal salt in the inorganic metal salt-ligand mixed solution is 8-50 mmol/L.
  13. 根据权利要求5所述的制备方法，其特征在于，所述水热反应的温度为130～150℃，时间为10～16h。The preparation method according to claim 5, characterized in that the temperature of the hydrothermal reaction is 130-150° C., and the time is 10-16 hours.
  14. 权利要求1～4任一项所述钒酸铋-金属有机配合物复合光电极或权利要求5～13任一项所述制备方法得到的钒酸铋-金属有机配合物复合光电极作为催化电极在光电催化水氧化反应中的应用。The bismuth vanadate-metal organic complex composite photoelectrode described in any one of claims 1 to 4 or the bismuth vanadate-metal organic complex composite photoelectrode obtained by the preparation method described in any one of claims 5 to 13 is used as a catalytic electrode Applications in photoelectrocatalytic water oxidation reactions.
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