A high-performance photoelectrode of sodium-doped bismuth copper acid composite bismuth vanadate and a preparation method thereof

Abstract

The application discloses a kind of sodium-doped bismuth copper acid composite bismuth vanadate high-performance photoelectrode and preparation method thereof, belong to electrode material technical field.The application provides sodium-doped bismuth copper acid composite bismuth vanadate high-performance photoelectrode comprising BiVO4 layer, Na-CuBi2O4 layer and nickel borate layer, sodium-doped bismuth copper acid layer as hole transport layer, passivates surface state, promotes the transport of carrier, reduces the recombination of surface charge, greatly improves the performance of electrode;Nickel borate layer improves the photo-corrosion defect of material, and stability is obviously improved;BiVO4 and Na-CuBi2O4 layer form heterojunction between simultaneously, improve the light absorption capacity of BiVO4, also enhance the separation efficiency of photo-generated carrier, finally get high-performance photoelectrode with high stability, high carrier separation efficiency and high surface catalytic oxygen production efficiency.

Description

Technical Field

[0001] This invention belongs to the field of electrode material technology, and particularly relates to a high-performance photoelectrode of sodium-doped copper bismuthate composite bismuth vanadate and its preparation method. Background Technology

[0002] Solar energy, as a clean and renewable energy source, is crucial for addressing the global energy crisis and climate change. Photoelectrochemical (PEC) technology offers a new and efficient way to utilize solar energy by directly converting it into chemical energy. This technology combines light-absorbing materials and electrochemical reactions to achieve the direct conversion and storage of solar energy, such as producing hydrogen through water splitting. PEC is environmentally friendly, efficient, and sustainable, and holds promise for providing innovative solutions for energy conversion and storage, driving the development of green energy technologies.

[0003] Bismuth vanadate (BiVO4) photoelectrochemical water splitting for hydrogen production is considered an eco-friendly, scalable, and sustainable method for solar energy conversion and storage. However, the low efficiency of the photoanode limits the development of photoelectrochemical (PEC) water splitting technology. BiVO4, as an n-type semiconductor photoanode material, has a band gap of approximately 2.4 eV and can absorb light with wavelengths of 300–520 nm, exhibiting a high efficiency of up to 7.5 mA cm⁻¹. -2 The theoretical photocurrent density of BiVO4 has attracted widespread attention in the scientific community. The conduction band position of BiVO4 is close to 0V vs. NHE, suitable for the reduction potential of H2, while the valence band is close to 2.5V vs. NHE, exhibiting strong catalytic oxygen production capabilities. However, unmodified BiVO4 suffers from weak light absorption, poor photogenerated carrier separation and transport performance, and poor surface catalytic oxygen production kinetics. Therefore, how to modify BiVO4 to achieve higher light absorption efficiency, photogenerated carrier separation efficiency, and surface catalytic oxygen production efficiency has become a pressing technical problem to be solved in this field.

[0004] Therefore, there is an urgent need for a method for growing large-size single crystals of alkali metal boron phosphate compounds that can guarantee the quality of single crystals in order to solve the above problems. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a high-performance photoelectrode of sodium-doped copper bismuthate composite bismuth vanadate and its preparation method.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a high-performance photoelectrode of sodium-doped copper bismuthate composite bismuth vanadate, comprising a conductive substrate and a BiVO4 (bismuth vanadate) layer, a Na-CuBi2O4 (sodium-doped copper bismuthate) layer and a nickel borate (NiBi) layer sequentially loaded on the conductive substrate.

[0008] The nickel borate layer is attached to the Na-CuBi2O4 layer and the BiVO4 layer.

[0009] Technical Principle: This invention provides a high-performance photoelectrode composed of sodium-doped copper bismuthate and bismuth vanadate, comprising a BiVO4 layer, a Na-CuBi2O4 layer, and a nickel borate (NiBi) layer. The sodium-doped copper bismuthate layer acts as a hole transport layer, passivating surface states, promoting carrier transport, reducing surface charge recombination, and greatly improving electrode performance. The NiBi layer improves the photocorrosion defects of the material, significantly enhancing stability. Simultaneously, a heterojunction is formed between the BiVO4 and Na-CuBi2O4 layers, improving the light absorption capacity of BiVO4 and enhancing the separation efficiency of photogenerated carriers. Ultimately, a high-performance photoelectrode with high stability, high carrier separation efficiency, and high surface catalytic oxygen production efficiency is obtained.

[0010] This invention also provides a method for preparing the high-performance photoelectrode of sodium-doped copper bismuthate composite bismuth vanadate as described in the above technical solution, comprising the following steps:

[0011] (1) BiVO4 is deposited on a conductive substrate to form a BiVO4 layer, thereby obtaining a BiVO4 photoelectrode;

[0012] (2) Dissolve sodium acetate in acetic acid, then add bismuth nitrate pentahydrate, sonicate, then add copper nitrate and ethanol to obtain a mixture; deposit the mixture on the BiVO4 photoelectrode obtained in step (1) to form a Na-CuBi2O4 layer, and obtain a composite photoelectrode of bismuth vanadate and sodium-doped copper bismuthate.

[0013] (3) Using the composite photoelectrode of bismuth vanadate and sodium-doped copper bismuthate obtained in step (2) as the working electrode, nickel sulfate hexahydrate is dissolved in potassium borate buffer solution as the electrolyte for photoelectrodeposition to form a nickel borate layer, thereby obtaining the high-performance photoelectrode of sodium-doped copper bismuthate composite bismuth vanadate.

[0014] This invention first deposits BiVO4 on a conductive substrate to obtain a BiVO4 photoelectrode, then adsorbs sodium-doped copper bismuthate onto the surface of the BiVO4 photoelectrode, and then performs photoelectrodeposition using a mixed solution of nickel sulfate hexahydrate and potassium borate buffer solution as the electrolyte to obtain a nickel borate (NiBi) layer, thereby obtaining a high-performance photoelectrode of sodium-doped copper bismuthate composite bismuth vanadate. The operation is simple and safe, the materials are readily available, and it can be mass-produced.

[0015] Furthermore, step (1) specifically involves:

[0016] A. Dissolve potassium iodide in nitric acid solution, then add bismuth nitrate pentahydrate and stir to obtain solution A; dissolve p-benzoquinone in ethanol to obtain solution B; mix solution A and solution B to obtain electrolyte A; deposit electrolyte A on a conductive substrate using an electrochemical method to obtain a conductive substrate with a BiOI thin film deposited.

[0017] B. Dissolve vanadium acetylacetonate in dimethyl sulfoxide to obtain solution C; drop solution C onto the conductive substrate with BiOI film deposited in step A, and then anneal at 430-480°C, followed by immersion in alkaline solution, rinsing, and drying to obtain BiVO4 photoelectrode.

[0018] Furthermore, in step A, the ratio of the amount of nitric acid solution, potassium iodide, and bismuth nitrate pentahydrate used is 25 mL: 0.4 mol: 0.04 mol; the pH value of the nitric acid solution is 1.6 to 1.8.

[0019] Furthermore, in step A, the ratio of p-benzoquinone to ethanol is 0.23 mol: 10 mL.

[0020] Furthermore, in step A, the process conditions for the deposition electrolyte A are as follows: initial voltage -0.1V, sampling interval 0.1s, deposition time 150–200s, settling time 0s, and sensitivity 1×10⁻⁶. -3 A.

[0021] Furthermore, in step A, the deposition method of the deposition electrolyte A is the time-current curve method; during deposition, the conductive substrate is the working electrode, the platinum mesh is the counter electrode, and Ag / AgCl is the reference electrode.

[0022] Furthermore, in step A, the conductive substrate is fluorine-doped tin oxide (FTO) conductive glass.

[0023] Furthermore, in step B, the ratio of acetylacetone vanadium oxide to dimethyl sulfoxide is 0.2 mol: 2 mL.

[0024] Furthermore, in step B, the dripping volume is 30 μL / cm. 2 .

[0025] Furthermore, in step B, the annealing process takes 2 hours.

[0026] Furthermore, in step B, the concentration of the alkaline solution used for the alkaline soaking is 1 mol / L; the alkaline solution is NaOH solution; and the soaking time is 15–25 minutes. This invention removes excess V₂O₅ through alkaline soaking.

[0027] Furthermore, in step (2), the ratio of acetic acid, sodium acetate, bismuth nitrate pentahydrate, and copper nitrate is 5 mL: 0.02 mmol: 0.04 mmol: 0.02 mmol. The reason why the ratio of acetic acid, sodium acetate, bismuth nitrate pentahydrate, and copper nitrate is controlled within the above range is that the synthesized sample has the best performance within this range.

[0028] Furthermore, in step (2), the deposition of the mixture is carried out by spray pyrolysis. Specifically, the BiVO4 photoelectrode is placed on a heating plate at a preset temperature of 250°C. A nozzle containing the mixture is positioned 15–30 cm above the heating plate, and the nozzle is driven to spray with an air overpressure of 55–70 kPa. The number of sprays is 5, the total spray time is 500–600 s, and the spray delay time is 50–55 s. The spray pyrolysis method for depositing the mixture has the advantages of simple process, good controllability, and strong scalability.

[0029] Furthermore, in step (2), the deposition mixture is followed by a heat treatment step; the temperature of the heat treatment is 450-460°C and the time is 5-10 min.

[0030] Furthermore, in step (3), the concentration of nickel sulfate hexahydrate in the electrolyte is 1 mmol / L.

[0031] Furthermore, in step (3), the concentration of the potassium borate buffer solution is 0.5 mol / L.

[0032] Furthermore, in step (3), the photoelectrodeposition process conditions are as follows: initial voltage is 0V, sampling interval is 0.1s, deposition time is 5-15s, settling time is 2s, and sensitivity is 1×10⁻⁶. -5 A, the light intensity is 100mW / cm² -2 The present invention deposits a NiBi layer under the above conditions, which can precisely form a NiBi layer on the photoactive sites.

[0033] Compared with the prior art, the present invention has the following advantages and technical effects:

[0034] This invention modifies a conductive substrate sequentially with bismuth vanadate, sodium-doped copper bismuthate, and nickel borate. The sodium-doped copper bismuthate attached to the surface of bismuth vanadate serves as a hole transport layer, thereby simultaneously improving the performance of the bismuth vanadate photoelectrode and protecting the bismuth vanadate. Meanwhile, nickel borate (NiBi) improves the photocorrosion defects of the material, significantly enhancing its stability. Ultimately, a high-performance photoelectrode with high stability, high carrier separation efficiency, and high surface catalytic oxygen production efficiency is obtained. Attached Figure Description

[0035] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0036] Figure 1 The image shows the SEM image of the BiVO4 photoelectrode in step (1) of Example 1.

[0037] Figure 2 SEM image of the NiBi / Na-CuBi2O4 / BiVO4 composite photoelectrode prepared in Example 1;

[0038] Figure 3 The XRD patterns are of the BiVO4 photoelectrode in step (1), the Na-CuBi2O4 / BiVO4 composite photoelectrode in step (2), and the NiBi / Na-CuBi2O4 / BiVO4 composite photoelectrode in step (3) of Example 1.

[0039] Figure 4 TEM image of the NiBi / Na-CuBi2O4 / BiVO4 composite photoelectrode prepared in Example 1;

[0040] Figure 5 The ultraviolet absorption spectra of the BiVO4 photoelectrode in step (1) and the Na-CuBi2O4 / BiVO4 composite photoelectrode in step (2) of Example 1 are shown.

[0041] Figure 6 The photoluminescence spectra of the BiVO4 photoelectrode in step (1), the Na-CuBi2O4 / BiVO4 composite photoelectrode in step (2), and the NiBi / Na-CuBi2O4 / BiVO4 composite photoelectrode in step (3) of Example 1 are shown.

[0042] Figure 7 The open-circuit potential diagrams are shown for the BiVO4 photoelectrode in step (1), the Na-CuBi2O4 / BiVO4 composite photoelectrode in step (2), and the NiBi / Na-CuBi2O4 / BiVO4 composite photoelectrode in step (3) of Example 1.

[0043] Figure 8 Linear scan voltammetric curves of the BiVO4 photoelectrode in step (1), the Na-CuBi2O4 / BiVO4 composite photoelectrode in step (2), and the NiBi / Na-CuBi2O4 / BiVO4 composite photoelectrode in step (3) of Example 1 in the presence of a hole trapping agent.

[0044] Figure 9Linear scan voltammetric curves of the BiVO4 photoelectrode in step (1), the Na-CuBi2O4 / BiVO4 composite photoelectrode in step (2), and the NiBi / Na-CuBi2O4 / BiVO4 composite photoelectrode in step (3) of Example 1 without a hole trapping agent. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0047] In this embodiment of the invention, room temperature refers to "25±2℃".

[0048] Unless otherwise specified, all raw materials used in the embodiments of this invention were purchased through commercial channels.

[0049] Example 1

[0050] A high-performance photoelectrode of sodium-doped copper bismuthate composite bismuth vanadate is composed of FTO conductive glass and BiVO4 layer, Na-CuBi2O4 layer and NiBi layer sequentially loaded on FTO conductive glass; the NiBi layer is attached to Na-CuBi2O4 layer and BiVO4 layer.

[0051] The fabrication process of the high-performance photoelectrode made of sodium-doped copper bismuthate and bismuth vanadate is as follows:

[0052] (1) Take a 20×15cm piece of FTO conductive glass, cut it into 2×3cm pieces using a glass cutting table, and then ultrasonically wash it for 15min each with acetone, ethanol, and tertiary water. After washing, dry it in an oven to obtain pretreated FTO conductive glass. Take 25mL of nitric acid solution with a pH of 1.7 and place it in a 100mL beaker. Add 0.4mol potassium iodide (KI) and 0.04mol bismuth nitrate pentahydrate (Bi(NO3)3·5H2O), and stir thoroughly until the solution is clear and transparent to obtain solution A. Take 10mL of anhydrous ethanol and place it in a beaker. Add 0.23mol p-benzoquinone and sonicate for 5min until the precipitate is completely dissolved to obtain solution B. Solution A and solution B were mixed and stirred vigorously to ensure complete miscibility, yielding electrolyte A. Electrolyte A was used as the electrolyte, with the pretreated FTO conductive glass as the working electrode, a platinum mesh as the counter electrode, and Ag / AgCl as the reference electrode. Electrodeposition was performed using the time-current curve method under the following conditions: initial voltage -0.1V, sampling interval 0.1s, deposition time 180s, settling time 0s, and sensitivity 1×10⁻⁶. -3 A. After electrodeposition, the film is rinsed with tertiary water and dried to obtain FTO conductive glass with a BiOI film deposited on it. This glass is then cut into 2×1cm pieces using a glass cutting stage and placed on a corundum sheet, with a 2mm distance between adjacent cut FTO conductive glasses. 2mL of dimethyl sulfoxide (DMSO) is added, and 0.2mol of vanadium acetylacetonate is stirred vigorously until no obvious precipitate is obtained, yielding solution C. 60μL (the amount used for each cut FTO conductive glass) of solution C is dropped onto the BiOI film surface using a 100μL pipette. The corundum sheet is then placed in a muffle furnace and heated to 450℃ at a rate of 2℃ / min, calcined for 2h, and then cooled to room temperature to obtain the calcined FTO conductive glass. The calcined FTO conductive glass is placed in a petri dish, and 1mol / L NaOH solution is added and soaked for 20min. It is then rinsed with tertiary water and dried to obtain a BiVO4 photoelectrode.

[0053] (2) Take 5 mL of acetic acid, add 0.02 mmol of anhydrous sodium acetate, sonicate for 20 min, then add 0.04 mmol of bismuth nitrate pentahydrate, sonicate for 15 min, then add 0.02 mmol of copper nitrate, sonicate to disperse, and then add 45 mL of anhydrous ethanol to obtain a mixture. Place the BiVO4 photoelectrode obtained in step (1) on a heating plate with a preset temperature of 250℃. Use a Yousuda UA-S120 nozzle. The nozzle containing the mixture is located 15 cm above the heating plate. Drive the nozzle to spray with an air overpressure of 55 kPa. Spray 5 times, spray for a total time of 500 s, and spray delay time of 55 s to complete the spray thermal decomposition. Then heat the air to 450℃ at a heating rate of 3℃ / min for heat treatment. After 5 min, a composite photoelectrode of bismuth vanadate and sodium-doped copper bismuthate (Na-CuBi2O4 / BiVO4 composite photoelectrode) is obtained.

[0054] (3) Prepare a 0.5 mol / L potassium borate buffer solution (pH = 9.5), add nickel sulfate hexahydrate (NiSO4·6H2O), and stir until the solution is clear and transparent to obtain electrolyte B with a nickel sulfate hexahydrate concentration of 1 mmol / L. Using electrolyte B as the electrolyte, the composite photoelectrode of bismuth vanadate and sodium-doped copper bismuthate obtained in step (2) is used as the working electrode, a platinum mesh as the counter electrode, and an Ag / AgCl electrode as the reference electrode. Electrodeposition is performed using the time-current curve method. The composite photoelectrode of bismuth vanadate and sodium-doped copper bismuthate is irradiated from the front. The electrodeposition process conditions are: initial potential 0 V, deposition temperature room temperature, running time 15 s, sampling interval 0.1 s, rest time 2 s, and sensitivity 1 × 10⁻⁶. -5 A, the light intensity is 100mW / cm² -2 After photoelectrode deposition, the working electrode was rinsed with ultrapure water and dried to obtain a high-performance photoelectrode of sodium-doped copper bismuthate composite bismuth vanadate (NiBi / Na-CuBi2O4 / BiVO4 composite photoelectrode).

[0055] Figure 1 This is a SEM image of the BiVO4 photoelectrode in step (1) of Example 1. From... Figure 1 It can be seen that the microstructure of the BiVO4 photoelectrode is worm-like nanoparticles.

[0056] Figure 2 This is a SEM image of the NiBi / Na-CuBi2O4 / BiVO4 composite photoelectrode prepared in Example 1. From... Figure 2 It can be seen that, compared with the BiVO4 photoelectrode, the NiBi / Na-CuBi2O4 / BiVO4 composite photoelectrode shows a large area of ​​fine particles on the surface of nanoparticles, indicating that NiBi and Na-CuBi2O4 have been deposited on the BiVO4 photoelectrode.

[0057] Figure 3 The images show the XRD patterns of the BiVO4 photoelectrode in step (1), the Na-CuBi2O4 / BiVO4 composite photoelectrode in step (2), and the NiBi / Na-CuBi2O4 / BiVO4 composite photoelectrode in step (3) of Example 1. Figure 3 It can be seen that the XRD pattern of the NiBi / Na-CuBi2O4 / BiVO4 composite photoelectrode shows the correlation diffraction peaks of BiVO4 and Na-CuBi2O4, while NiBi is an amorphous layer material without a crystalline structure, and therefore there are no NiBi-related diffraction peaks. This preliminarily proves the successful preparation of the NiBi / Na-CuBi2O4 / BiVO4 composite photoelectrode.

[0058] Figure 4 This is a TEM image of the NiBi / Na-CuBi2O4 / BiVO4 composite photoelectrode prepared in Example 1. From... Figure 4 It can be seen that there is a layer of NiBi on the surface of the bismuth vanadate nanoparticles, and a Na-CuBi2O4 lattice is also present, indicating that Na-CuBi2O4 and NiBi have been attached to the BiVO4 photoelectrode.

[0059] Figure 5 The images show the UV absorption spectra of the BiVO4 photoelectrode in step (1) and the Na-CuBi2O4 / BiVO4 composite photoelectrode in step (2) of Example 1. Figure 5 As can be seen, compared with the unmodified BiVO4 photoelectrode, the Na-CuBi2O4 / BiVO4 composite photoelectrode slightly expands the light absorption range.

[0060] Figure 6 The images show the photoluminescence spectra of the BiVO4 photoelectrode in step (1), the Na-CuBi2O4 / BiVO4 composite photoelectrode in step (2), and the NiBi / Na-CuBi2O4 / BiVO4 composite photoelectrode in step (3) of Example 1. Figure 6 It can be seen that, compared with the unmodified BiVO4 photoelectrode, the emission intensity of the NiBi / Na-CuBi2O4 / BiVO4 composite photoelectrode obtained by loading BiVO4 with NiBi and Na-CuBi2O4 is reduced, thereby suppressing carrier recombination.

[0061] Figure 7 This is a diagram showing the open-circuit potential (OCP) of the BiVO4 photoelectrode in step (1), the Na-CuBi2O4 / BiVO4 composite photoelectrode in step (2), and the NiBi / Na-CuBi2O4 / BiVO4 composite photoelectrode in step (3) of Example 1. From... Figure 7It can be seen that, compared with the unmodified BiVO4 photoelectrode, the NiBi / Na-CuBi2O4 / BiVO4 composite photoelectrode has a larger OCP value, which means a more favorable driving force for water oxidation.

[0062] Figure 8 Linear scan voltammetric curves of the BiVO4 photoelectrode in step (1), the Na-CuBi2O4 / BiVO4 composite photoelectrode in step (2), and the NiBi / Na-CuBi2O4 / BiVO4 composite photoelectrode in step (3) of Example 1, in the presence of a hole trapping agent. Figure 8 It can be seen that, under test conditions with hole trapping agents, the NiBi / Na-CuBi2O4 / BiVO4 composite photoelectrode can achieve a higher photocurrent density under the same external voltage after loading NiBi layer and Na-CuBi2O4.

[0063] Figure 9 Linear scan voltammetric curves of the BiVO4 photoelectrode in step (1), the Na-CuBi2O4 / BiVO4 composite photoelectrode in step (2), and the NiBi / Na-CuBi2O4 / BiVO4 composite photoelectrode in step (3) of Example 1, without a hole trapping agent. Figure 9 It can be seen that, under test conditions without hole trapping agent, the photocurrent of the NiBi / Na-CuBi2O4 / BiVO4 composite photoelectrode was significantly improved after adding the NiBi layer and the Na-CuBi2O4 layer. At 1.23V (vs. RHE), the photocurrent increased by 2.8 times.

[0064] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A high-performance photoelectrode of sodium-doped copper bismuthate composite bismuth vanadate, characterized in that, It includes a conductive substrate and a BiVO4 layer, a Na-CuBi2O4 layer and a nickel borate layer sequentially loaded on the conductive substrate; The nickel borate layer is attached to the Na-CuBi2O4 layer and the BiVO4 layer.

2. A method for preparing a high-performance photoelectrode of sodium-doped copper bismuthate composite bismuth vanadate as described in claim 1, characterized in that, Includes the following steps: (1) BiVO4 is deposited on a conductive substrate to form a BiVO4 layer, thereby obtaining a BiVO4 photoelectrode; (2) Dissolve sodium acetate in acetic acid, then add bismuth nitrate pentahydrate, sonicate, then add copper nitrate and ethanol to obtain a mixture; deposit the mixture on the BiVO4 photoelectrode obtained in step (1) to form a Na-CuBi2O4 layer, and obtain a composite photoelectrode of bismuth vanadate and sodium-doped copper bismuthate. (3) Using the composite photoelectrode of bismuth vanadate and sodium-doped copper bismuthate obtained in step (2) as the working electrode, nickel sulfate hexahydrate is dissolved in potassium borate buffer solution as the electrolyte for photoelectrodeposition to form a nickel borate layer, thereby obtaining the high-performance photoelectrode of sodium-doped copper bismuthate composite bismuth vanadate.

3. The method for preparing the high-performance photoelectrode of sodium-doped copper bismuthate composite bismuth vanadate according to claim 2, characterized in that, Step (1) specifically involves: A. Dissolve potassium iodide in nitric acid solution, then add bismuth nitrate pentahydrate and stir to obtain solution A; dissolve p-benzoquinone in ethanol to obtain solution B; mix solution A and solution B to obtain electrolyte A; deposit electrolyte A on a conductive substrate using an electrochemical method to obtain a conductive substrate with a BiOI thin film deposited. B. Dissolve vanadium acetylacetonate in dimethyl sulfoxide to obtain solution C; drop solution C onto the conductive substrate with BiOI film deposited in step A, and then anneal at 430-480°C, followed by immersion in alkaline solution, rinsing, and drying to obtain BiVO4 photoelectrode.

4. The method for preparing the high-performance photoelectrode of sodium-doped copper bismuthate composite bismuth vanadate according to claim 3, characterized in that, In step A, the ratio of the nitric acid solution, potassium iodide, and bismuth nitrate pentahydrate is 25 mL : 0.4 mol : 0.04 mol; the pH of the nitric acid solution is 1.6–1.8; and / or, The ratio of p-benzoquinone to ethanol is 0.23 mol: 10 mL; and / or, The process conditions for the deposition electrolyte A are as follows: initial voltage -0.1V, sampling interval 0.1s, deposition time 150–200s, settling time 0s, and sensitivity 1×10⁻⁶. -3 A.

5. The method for preparing the high-performance photoelectrode of sodium-doped copper bismuthate composite bismuth vanadate according to claim 3, characterized in that, In step B, the ratio of acetylacetone vanadium oxide to dimethyl sulfoxide is 0.2 mol: 2 mL; and / or, The dripping volume is 30 μL / cm. 2 ; and / or, The annealing process takes 2 hours.

6. The method for preparing a high-performance photoelectrode of sodium-doped copper bismuthate composite bismuth vanadate according to claim 2, characterized in that, In step (2), the ratio of acetic acid, sodium acetate, bismuth nitrate pentahydrate and copper nitrate is 5 mL: 0.02 mmol: 0.04 mmol: 0.02 mmol.

7. The method for preparing a high-performance photoelectrode of sodium-doped copper bismuthate composite bismuth vanadate according to claim 2, characterized in that, In step (2), the deposition of the mixture is carried out by spray thermal decomposition. Specifically, the BiVO4 photoelectrode is placed on a heating plate at a preset temperature of 250°C. The nozzle containing the mixture is located 15-30 cm above the heating plate and sprayed with an air overpressure of 55-70 kPa. The number of sprays is 5, the total spray time is 500-600 s, and the spray delay time is 50-55 s.

8. The method for preparing a high-performance photoelectrode of sodium-doped copper bismuthate composite bismuth vanadate according to claim 2, characterized in that, In step (2), the deposition mixture is followed by a heat treatment step; the temperature of the heat treatment is 450-460℃ and the time is 5-10 min.

9. The method for preparing a high-performance photoelectrode of sodium-doped copper bismuthate composite bismuth vanadate according to claim 2, characterized in that, In step (3), the concentration of nickel sulfate hexahydrate in the electrolyte is 1 mmol / L.

10. The method for preparing a high-performance photoelectrode of sodium-doped copper bismuthate composite bismuth vanadate according to claim 2, characterized in that, In step (3), the photoelectrodeposition process conditions are as follows: initial voltage is 0V, sampling interval is 0.1s, deposition time is 5-15s, settling time is 2s, and sensitivity is 1×10⁻⁶. -5 A, the light intensity is 100 mW·cm -2 .

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