Method for preparing bismuth vanadate photo-anode material through oxygen-enriched calcination and application of bismuth vanadate photo-anode material

Abstract

The invention discloses a method for preparing a bismuth vanadate photo-anode material through oxygen-enriched calcination and application, and belongs to the technical field of photoelectrocatalysis. The method comprises the following steps: step 1, preparing a mixed solution of vanadyl acetylacetonate and dimethyl sulfoxide; 2, dropwise adding a mixed solution of vanadyl acetylacetonate and dimethyl sulfoxide to the surface of the BiOI thin film, transferring the BiOI thin film to an oxygen-enriched atmosphere environment in which the O2 content accounts for 40-80%, heating to a calcination temperature, and maintaining a constant-temperature reaction; and 3, after the constant-temperature reaction is finished, cooling to room temperature, and cleaning to obtain the clean bismuth vanadate photo-anode material. According to the bismuth vanadate photo-anode material prepared through the method, effective separation of photon-generated carriers can be achieved, the photoelectrocatalysis water oxidation performance is remarkably improved, and more possibilities are provided for preparing and storing clean energy in the future.

Description

Technical Field

[0001] This invention relates to the field of photoelectrocatalysis technology, specifically to a method for preparing bismuth vanadate photoanode materials by oxygen-enriched calcination and its application. Background Technology

[0002] With the development of modern industries, people's demand for energy is increasing, leading to energy crises and environmental pollution, which have become urgent problems to be solved. Utilizing solar energy for photoelectric water splitting to produce hydrogen is undoubtedly a breakthrough renewable energy method, and many scholars have already conducted research and reported on it.

[0003] Among numerous photoanode materials for water electrolysis, bismuth vanadate has attracted widespread attention due to its suitable band edge position, excellent photoresponse capability, and advantages such as non-toxicity and low cost. Bismuth vanadate (BiVO4) has a theoretical maximum current density of 7.5 mA / cm². 2 BiVO4 has a photoelectric conversion efficiency of 9.2% for light energy to hydrogen (STH), making it one of the most promising photoanode materials. However, BiVO4 films synthesized under natural conditions have low V / Bi ratios and low photocurrent densities. The V element in the film is easily affected by factors such as volatility, leading to an imbalance in the stoichiometric ratio. Therefore, it is necessary to control defects to achieve a balanced stoichiometric ratio. Moreover, the low electron mobility of pure BiVO4 photoanode semiconductors leads to easy recombination of photogenerated electron-hole pairs, preventing a large number of charge carriers from participating in the photoelectrocatalytic reaction. This severely limits the improvement of photocurrent density and photoelectric conversion efficiency. Technical means are needed to suppress charge recombination and extend the lifetime of photogenerated charge carriers.

[0004] Conventional methods for controlling the surface element ratio mainly involve introducing excess vanadium sources through various chemical or thermal post-treatments. For example, in the paper "Tailoring the surface termination of BiVO4 photoanodes using ammonium metavanadate enhances the solar water oxidation performance," by Q. Wang, Z. Wang, N. Liao, S. Montilla-Verdú, M. Contreras, N. Guijarro, J. Luo, "Tailoring the surface termination of BiVO4 photoanodes using ammonium metavanadate enhances the solar water oxidation performance," ACS Energy Lett. 9 (2024) 3308-3315, https: / / doi.org / 10.1021 / acsenergylett.4c01240," ammonium metavanadate was used as the vanadium source precursor, and the surface of BiVO4 photoanodes was modified by chemical post-treatment. By introducing excess vanadium sources into the photoanode surface, precise control of the BiVO4 surface termination layer was achieved, successfully constructing a vanadium-rich surface structure. This optimized key performance characteristics of the photoanode, such as interfacial charge transport, light absorption, and catalytic active sites. For another example, Nengcong Yang, Sainan Zhang, Dr. Yejun Xiao, Dr. Yu Qi, Dr. Yunfeng Bao, Peng Xu, Prof. Dr. Shengye Jin, Prof. Dr. Fuxiang Zhang. Insight into the KeyRestriction of BiVO4Photoanodes Prepared by Pyrolysis Method for ScalablePreparation.https: / / doi.org / 10.1002 / anie.202308729Digital Object The article in the Identifier (DOI) focuses on the core limiting factors and optimization strategies for the preparation of BiVO4 photoanodes by the organometallic decomposition (MOD) pyrolysis method. It was found that vanadium is easily volatilized and lost during the pyrolysis process, which in turn generates tetragonal phase impurities and inhibits the separation of photogenerated charges. To address this, the study added an excess of vanadium precursor in the post-treatment stage and used high-temperature thermal diffusion to compensate for vanadium loss, successfully eliminating tetragonal phase impurities and obtaining pure monoclinic phase BiVO4 photoanodes. This provides a feasible path for the large-scale preparation of high-efficiency BiVO4 photoanodes. However, the above-mentioned chemical or thermal post-treatment methods increase the complexity of the synthesis and limit its large-scale application.Therefore, how to optimize the preparation environment and precisely control the chemical dosage ratio through simple methods to improve the photoelectric conversion efficiency of bismuth vanadate photoanode materials remains one of the technical challenges that researchers in this field urgently need to solve. Summary of the Invention

[0005] This invention provides a method and application for preparing bismuth vanadate photoanode materials by oxygen-enriched calcination, based on the existing method for preparing BiVO4 thin films by electrodeposition.

[0006] The present invention achieves the above objectives through the following technical solutions: As a first aspect of the present invention, a method for preparing bismuth vanadate photoanode materials by oxygen-enriched calcination is provided, the method comprising the following steps: Step 1: Prepare a mixed solution of acetylacetone vanadium oxide and dimethyl sulfoxide; Step 2: Add a mixed solution of vanadium acetylacetonate and dimethyl sulfoxide to the surface of the BiOI film, and transfer it to an oxygen-rich atmosphere with an O2 content of 40-80%. After heating to the calcination temperature, maintain the reaction at a constant temperature. Step 3: After the isothermal reaction is completed, cool it to room temperature and then clean it to obtain clean bismuth vanadate photoanode material.

[0007] As a further optimization of the present invention, in step one, the content of acetylacetone vanadium oxide in the mixed solution of acetylacetone vanadium oxide and dimethyl sulfoxide is 0.2 M, and the volume of dimethyl sulfoxide is 5 ml.

[0008] As a further optimization of the present invention, in step two, the oxygen-rich atmosphere is a mixture of O2 and Ar, with the O2 content accounting for 60%.

[0009] As a further optimization of the present invention, in step two, the volume of the mixed solution of acetylacetonate vanadium and dimethyl sulfoxide added is 100 μL.

[0010] As a further optimization of the present invention, in step two, the heating time is 3.5 h, the calcination temperature is 450℃, and the constant temperature reaction time is 2 h.

[0011] As a further optimization of the present invention, the cleaning process in step three is as follows: first, soaking in a 1 mol / L NaOH solution to remove surface impurities, then rinsing repeatedly with deionized water until neutral, and finally vacuum drying and air drying.

[0012] As a further optimization of the present invention, the method for preparing the BiOI thin film includes the following steps: (1) Adjust the pH of 50 ml, 20 mM KI solution to 1.7 with nitric acid, add 2 mM Bi(NO3)3·5H2O and stir until the solution is clear; (2) Dissolve 0.5 g of p-benzoquinone in 20 ml of anhydrous ethanol and stir until clear to obtain a p-benzoquinone ethanol solution;

[0013] (3) Slowly pour the p-benzoquinone ethanol solution into the solution of step (1), and stir to mix to obtain the electrodeposition solution; (4) Place the electrodeposition solution in an electrolytic cell, use a clean FTO glass as the working electrode, a Pt electrode as the counter electrode, and an Ag / AgCl as the reference electrode. Use a three-electrode system to deposit for 50-500 s at a bias voltage of -0.1 V to obtain a red sheet-like BiOI film. Take it out and rinse it with deionized water to remove the residual solution on the surface. Let it dry at room temperature.

[0014] As a further optimization of the present invention, in step (4), the FTO glass is first rinsed with deionized water, then ultrasonically cleaned with acetone and anhydrous ethanol for 15-30 min, and finally dried at 40-60 ℃ for 20-30 min for later use.

[0015] As a second aspect of the present invention, a bismuth vanadate photoanode material prepared by the method described in any one of the preceding claims is also provided, wherein the bismuth vanadate photoanode material has a V / Bi ratio of 0.982-1.1313 and a photocurrent density of 1.39-1.88 mA / cm² at a voltage of 1.23 V vs. RHE. 2 The separation efficiency is 69.6-84.4%.

[0016] As a third aspect of the present invention, an application of the bismuth vanadate photoanode material as described above in the field of photoelectrocatalysis is also provided.

[0017] The beneficial effects of this invention are as follows: The bismuth vanadate photoanode material of the present invention is prepared by a three-electrode deposition method combined with an oxygen-enriched calcination method. The method is simple and easy to implement. The oxygen-enriched calcination method makes up for the V element defects on the surface of the bismuth vanadate photoanode, optimizes the surface V / Bi ratio, realizes the chemical dosing ratio balance, and inhibits the severe electron-hole recombination caused by surface defects in the bismuth vanadate photoanode. Through investigation, this invention revealed that the V / Bi ratio in pristine BiVO4 prepared under air atmosphere is 0.62, while the V / Bi ratio in BiVO4 prepared under an oxygen-rich atmosphere with an O2 content of 60% is 1.1313. Furthermore, it exhibits a maximum voltage of 1.88 mA / cm² at 1.23 V vs. RHE. 2 Photocurrent density, compared to the original BiVO4 (1.14 mA / cm²).2 It increased by 0.74 mA / cm 2 Furthermore, the separation efficiency of the BiVO4 photoanode material prepared in an oxygen-rich atmosphere with an O2 content of 60% significantly increased from 65.2% of the original BiVO4 to 84.4% at a voltage of 1.23 V vs. RHE. This indicates that the oxygen-rich atmosphere significantly suppressed charge recombination, increased the photocurrent density of the material, promoted charge transfer and separation, and improved the lifetime of photogenerated carriers. To address the issues of low photogenerated charge separation efficiency and weak water oxidation kinetics in existing BiVO4 photoanode materials, the bismuth vanadate photoanode material prepared by the method of this invention can achieve effective separation of photogenerated charge carriers, significantly improving the photoelectrocatalytic water oxidation performance and providing more possibilities for the future preparation and storage of clean energy. Attached Figure Description

[0018] Figure 1 SEM (Scanning Electron Microscopy) comparison images of BVO-40, BVO-60, BVO-80, and BVO provided for this invention; Figure 2 XPS full spectrum comparison diagrams of BVO-40, BVO-60, BVO-80 and BVO provided for this invention; Figure 3 High-resolution Bi 4f photoelectron spectra comparison diagrams of BVO-40, BVO-60, BVO-80 and BVO provided for this invention; Figure 4 Comparison of O 1s photoelectron spectra of BVO-40, BVO-60, BVO-80 and BVO provided for this invention; Figure 5 Comparison of V 2p photoelectron spectra of BVO-40, BVO-60, BVO-80 and BVO provided for this invention; Figure 6 A comparison chart of linear sweep voltammetry (LSV) curves of BVO-40, BVO-60, BVO-80, and BVO provided for this invention; Figure 7 A comparison of linear sweep voltammetry (LSV) curves of BVO-40, BVO-60, BVO-80, and BVO measured in 0.5 mol / L Na2SO3 (hole trapping agent) solution provided for this invention; Figure 8 A comparison chart of the photogenerated charge separation efficiency of BVO-40, BVO-60, BVO-80, and BVO provided for this invention; Figure 9 A comparison diagram of the AC impedance of BVO-60 and BVO provided for this invention; Figure 10 Fluorescence test curves of BVO-40, BVO-60, BVO-80, and BVO provided for this invention. Detailed Implementation

[0019] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0020] In the following embodiments, the FTO glass used has a size range of 1 cm × 2.5 cm to 2 cm × 4 cm, and is preferably 1 cm × 2.5 cm.

[0021] 1. Preparation of BiOI thin films (1.1) Take FTO glass, rinse it with deionized water, then ultrasonically clean it with acetone and anhydrous ethanol for 15-30 min (preferably 30 min), and then place it in an electric heating drying oven and dry it at 40-60 ℃ (preferably 60 ℃) for 20-30 min (preferably 30 min) for later use.

[0022] (1.2) Add 50 ml of deionized water to a 100 ml beaker, add 20 mM KI, stir until clear, then add nitric acid to adjust the pH to 1.7, and then add 2 mM Bi(NO3)3·5H2O and stir until the solution is clear.

[0023] (1.3) Take 20 ml of anhydrous ethanol and add it to a 50 ml beaker. Add 0.5 g of p-benzoquinone and stir until clear.

[0024] (1.4) Slowly pour the clarified solution obtained in step (3) into the solution in step (2), and stir to mix to obtain the electrodeposition solution; (1.5) Place the electrodeposition solution obtained in step (4) in an electrolytic cell, use the FTO glass from step (1) as the working electrode, the Pt electrode as the counter electrode, and the Ag / AgCl as the reference electrode, and use a three-electrode system to deposit for 100-500 s (preferably 300 s) at a bias voltage of -0.1 V to obtain a red sheet-like BiOI film. After the deposition is completed, take it out and rinse it with deionized water to remove the residual solution on the surface, and air dry it at room temperature.

[0025] 2. Preparation of BiVO4(O) photoanode material (2.1) 100 μL of a pre-prepared mixed solution consisting of 0.2 M acetylacetonate vanadium oxide and 5 mL dimethyl sulfoxide solution was dropped onto the prepared BiOI film.

[0026] (2.2) Place it in the center of a tubular furnace (the furnace is under normal pressure) and introduce O2 and Ar mixtures with different O2 content ratios (40%, 60%, 80%) (Table 1). The flow rate of the mixture is 100 cc / min and the velocity range is 0.074-0.080 cm / s. Heat it up to 450 ℃ in 3.5 hours and keep it at that temperature for 2 hours.

[0027] (2.3) After the furnace cools down to room temperature, take out the material and soak it in a 1 mol / L NaOH solution for 5 minutes. After the impurities such as V2O5 on the surface of the material are completely dissolved, take it out, rinse it with deionized water, and air dry it at room temperature to obtain BiVO4(O) photoanode material.

[0028] BiVO4(O) photoanode materials were prepared by introducing O2 and Ar mixtures with different O2 content ratios (40%, 60%, and 80%), and were designated as BVO-40, BVO-60, and BVO-80, respectively.

[0029] In addition, the BiVO4 photoanode material prepared in an air atmosphere was used as a control and named BVO.

[0030] Table 1. O2 and Ar mixture composition design

[0031] 3. Performance Characterization 3.1 Scanning Electron Microscopy (SEM) Analysis BVO-40, BVO-60, BVO-80, and BVO were analyzed by scanning electron microscopy (SEM). The results are as follows: Figure 1 As shown, the BiVO4 photoanode material BVO obtained by calcination in an air atmosphere exhibits a typical nanoporous structure and a smooth surface. Figure 1 (Figure (a)); and the BiVO4(O) photoanode materials obtained by calcination in a mixed atmosphere of O2 and Ar with different O2 contents (40%, 60%, 80%) showed a significant increase in particle size for BVO-40, BVO-60, and BVO-80. Figure 1 (See Figures (b), (c), and (d)). This leads to a reduction in the number of grain boundaries, which helps to suppress carrier recombination.

[0032] 3.2 X-ray photoelectron spectroscopy (XPS) analysis X-ray photoelectron spectroscopy (XPS) analysis was performed on BVO-40, BVO-60, BVO-80, and BVO.

[0033] Figure 2 The XPS full spectrum comparison images of BVO-40, BVO-60, BVO-80, and BVO are shown. The images reveal that the V to Bi ratios in the BVO, BVO-40, BVO-60, and BVO-80 samples are 0.620, 0.982, 1.313, and 1.312, respectively. It can be seen that the atomic ratio in BVO deviates significantly from the stoichiometry, indicating a large presence of V vacancies on the surface. Furthermore, the V content increases with increasing O2 content, confirming that calcination in an oxygen-enriched atmosphere can be used to compensate for V defects in the crystal.

[0034] Figure 3 Comparison of high-resolution Bi 4f photoelectron spectra of BVO-40, BVO-60, BVO-80, and BVO. The figures show that the Bi 4f of BVO... 7 / 2 and Bi 4f 5 / 2 The peaks at 159.1 eV and 164.4 eV confirm that Bi 3+ The presence of bismuth is evident. For BVO, BVO-40, and BVO-60, the Bi 4f peak remains almost unchanged. Only under highly oxygen-rich conditions with an O2 content of 80% does BVO-80 show a significant increase in binding energy, indicating the presence of unfavorable electronic structure recombination related to bismuth under lower oxygen partial pressures.

[0035] Figure 4 Comparison of O 1s photoelectron spectra of BVO-40, BVO-60, BVO-80, and BVO. The O 1s peaks of BVO-40, BVO-60, BVO-80, and BVO show the O... OH O V and O L The binding energies of the three characteristic peaks increase towards higher binding energies.

[0036] Figure 5 Comparison of V 2p photoelectron spectra of BVO-40, BVO-60, BVO-80, and BVO. The peak of BVO in the V 2p spectrum is located at 516.5, corresponding to V 2p. 3 / 2 This component is due to V in BiVO4. 5+ The presence of [missing information]. Compared to BVO, a slight shift of V 2p towards higher binding energies can be observed in BVO-40, BVO-60, and BVO-80.

[0037] This trend indicates unfavorable Bi-related electronic structure reorganization under lower oxygen partial pressures. The O 1s shift reflects enhanced surface oxidation, while the V 2p shift indicates a gradual increase in the oxidation state of V on the material surface, reflecting the shift from low-valence to fully oxidized V. 5+ Transformation. Ultimately, all these phenomena indicate that surface V defects are significantly suppressed, which will help reduce carrier recombination.

[0038] 3.3 Photoelectrochemical performance testing Electrochemical performance was tested using a square electrolytic cell and a three-electrode system. The BVO-40, BVO-60, BVO-80, and BVO electrodes prepared above were used as working electrodes, platinum wire as the counter electrode, and an Ag / AgCl electrode as the reference electrode for photoelectrochemical performance analysis. 0.25 M potassium borate solution (pH=9.5) and 0.5 M Na₂SO₃ solution were used as electrolytes, a xenon lamp (model MC-SXE300+) was used as the simulated light source, and an AM 1.5 G filter was used for illuminance at 100 mW / cm². 2 Current density versus voltage characteristic (JV) curves were obtained using a linear scanning voltammetry method with a scan rate of 100 mV / s. All measurement units were converted to RHE (E). RHE =E Ag / AgCl +0.197 V +0.059 pH).

[0039] The results are as follows Figure 6 As shown, the photocurrent density of photoanode materials (BVO-40, BVO-60, BVO-80) prepared in a tube furnace with different O2 content ratios of mixed O2 and Ar atmospheres is superior to that of BVO prepared in an air atmosphere. The original BVO at 1.23 V... RHE The photocurrent density was 1.14 mA / cm². 2 The photocurrent densities of BVO-40, BVO-60, and BVO-80 are 1.59 mA / cm², respectively. 2 1.88 mA / cm 2 and 1.39 mA / cm 2 The increase in photocurrent density indicates that the V vacancies on the material surface have been improved.

[0040] Figure 7 The image shows the linear sweep voltammetry (LSV) curves measured in 0.5 M Na₂SO₃ solution. At a voltage of 1.23 V vs. RHE, the photocurrent densities for BVO-40, BVO-60, BVO-80, and BVO are 5.15 mA / cm², respectively. 2 5.74 mA / cm 2 4.73 mA / cm2 and 4.44 mA / cm 2 For BVO-40, BVO-60, and BVO-80, the increase in photocurrent density also means that the V vacancies on the material surface have been improved.

[0041] The photogenerated charge separation efficiency is the ratio of the photocurrent density measured in a 0.5 M Na2SO3 solution to the photocurrent density when the absorbed photons are completely converted into current. Figure 8 The graph shows a comparison of the photogenerated charge separation efficiencies of BVO-40, BVO-60, BVO-80, and BVO. As can be seen from the graph, the separation efficiency of the BVO-40, BVO-60, and BVO-80 photoanodes at 1.23 V vs. RHE significantly increased from 65.2% for BVO to 75.7%, 84.4%, and 69.6%, respectively. This indicates that preparation in an oxygen-rich atmosphere significantly suppressed charge recombination, with the most pronounced suppression effect observed at an oxygen content of 60%.

[0042] 3.4 Electrochemical Impedance Spectroscopy (EIS) Test In the electrochemical impedance spectroscopy (EIS) experiment, the AC frequency was controlled to vary from 100 mHz to 100 kHz, and an AC bias potential was applied. The test was performed under illumination conditions, with an initial potential of 1.23 V vs. RHE. After the measurement, a Nyquist plot was displayed, which is typically a semicircle with a radius proportional to the charge transfer resistance.

[0043] Figure 9 The diagram shows a comparison of the AC impedance of BVO-40, BVO-60, BVO-80, and BVO. The comparison reveals that the electron transfer resistance (Rct) of the photoanode materials prepared in an oxygen-rich atmosphere is lower than that of BiVO4. BVO-60 exhibits the lowest Rct value, indicating enhanced interfacial charge transport and transfer.

[0044] 3.5 Time-Resolved Photoluminescence (TRPL) Test Time-resolved photoluminescence (TRPL, Edinburgh FLS1000) results were collected using an EPL375 laser. In fluorescence spectroscopy experiments, the sample is first irradiated with an excitation source, typically ultraviolet or visible light. After excitation, the fluorescence signal emitted by the sample is collected and analyzed by a spectrometer.

[0045] Figure 10The fluorescence test curves for BVO-60 and BVO are shown. A comparison reveals that the average lifetime of BVO is 5.34 ns, while that of BVO-60 is 13.23 ns, approximately 2.48 times that of BVO. This indicates that in BVO-60, the recombination of photogenerated electron-hole pairs is effectively suppressed, which can increase the photocurrent density of the photoanode.

[0046] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for preparing bismuth vanadate photoanode material by oxygen-enriched calcination, characterized in that, The method includes the following steps: Step 1: Prepare a mixed solution of acetylacetone vanadium oxide and dimethyl sulfoxide; Step 2: Add a mixed solution of vanadium acetylacetonate and dimethyl sulfoxide to the surface of the BiOI film, and transfer it to an oxygen-rich atmosphere with an O2 content of 40-80%. After heating to the calcination temperature, maintain the reaction at a constant temperature. Step 3: After the isothermal reaction is completed, cool it to room temperature and then clean it to obtain clean bismuth vanadate photoanode material.

2. The method for preparing bismuth vanadate photoanode material by oxygen-enriched calcination according to claim 1, characterized in that, In step one, the content of acetylacetone vanadium oxide in the mixed solution of acetylacetone vanadium oxide and dimethyl sulfoxide is 0.2 M, and the volume of dimethyl sulfoxide is 5 ml.

3. The method for preparing bismuth vanadate photoanode material by oxygen-enriched calcination according to claim 1, characterized in that, In step two, the oxygen-rich atmosphere is a mixture of O2 and Ar, with O2 accounting for 60%.

4. The method for preparing bismuth vanadate photoanode material by oxygen-enriched calcination according to claim 1, characterized in that, In step two, the volume of the mixed solution of acetylacetonate vanadium and dimethyl sulfoxide added is 100 μL.

5. The method for preparing bismuth vanadate photoanode material by oxygen-enriched calcination according to claim 1, characterized in that, In step two, the heating time is 3.5 h, the calcination temperature is 450 ℃, and the constant temperature reaction time is 2 h.

6. The method for preparing bismuth vanadate photoanode material by oxygen-enriched calcination according to claim 1, characterized in that, In step three, the cleaning process involves first soaking the surface in a 1 mol / L NaOH solution to remove impurities, then rinsing it repeatedly with deionized water until neutral, and finally vacuum drying and air drying.

7. The method for preparing bismuth vanadate photoanode material by oxygen-enriched calcination according to claim 1, characterized in that, The method for preparing the BiOI thin film includes the following steps: (1) Adjust the pH of 50 ml, 20 mM KI solution to 1.7 with nitric acid, add 2 mM Bi(NO3)3·5H2O and stir until the solution is clear; (2) Dissolve 0.5 g of p-benzoquinone in 20 ml of anhydrous ethanol and stir until clear to obtain a p-benzoquinone ethanol solution; (3) Slowly pour the p-benzoquinone ethanol solution into the solution of step (1), and stir to mix to obtain the electrodeposition solution; (4) Place the electrodeposition solution in an electrolytic cell, use a clean FTO glass as the working electrode, a Pt electrode as the counter electrode, and an Ag / AgCl as the reference electrode. Use a three-electrode system to deposit for 50-500 s at a bias voltage of -0.1 V to obtain a red sheet-like BiOI film. Take it out and rinse it with deionized water to remove the residual solution on the surface. Let it dry at room temperature.

8. The method for preparing bismuth vanadate photoanode material by oxygen-enriched calcination according to claim 7, characterized in that, In step (4), the FTO glass is first rinsed with deionized water, then ultrasonically cleaned with acetone and anhydrous ethanol for 15-30 min, and finally dried at 40-60 ℃ for 20-30 min for later use.

9. A bismuth vanadate photoanode material prepared by the method according to any one of claims 1-8, characterized in that, The bismuth vanadate photoanode material has a V / Bi ratio of 0.982-1.1313, and a photocurrent density of 1.39-1.88 mA / cm² at a voltage of 1.23 V vs. RHE. 2 The separation efficiency is 69.6-84.4%.

10. An application of the bismuth vanadate photoanode material as described in claim 9 in the field of photoelectrocatalysis.

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