A boron-doped Cu x O2 composite bismuth vanadate photoelectrode

Abstract

This invention discloses a boron-doped Cu x The O2 composite bismuth vanadate photoelectrode belongs to the field of photoelectrochemical analysis technology. The boron-doped Cu of this invention... x The preparation method of the O2 composite bismuth vanadate photoelectrode includes the following steps: adding potassium iodide and bismuth nitrate to a nitric acid solution to obtain solution A; mixing solution A with a p-benzoquinone solution to obtain electrolyte A; using electrolyte A as the electrolyte, performing a first electrochemical deposition on the surface of the working electrode to obtain a working electrode with a deposited BiOI film; coating the surface of the working electrode with the deposited BiOI film with an acetylacetone vanadium oxide solution, performing a first annealing treatment, and then alkali washing to obtain the bismuth vanadate photoelectrode; adding copper nitrate to a potassium borate buffer solution to obtain electrolyte B; using electrolyte B as the electrolyte, performing a second electrochemical deposition on the surface of the bismuth vanadate photoelectrode, and then performing a second annealing treatment to complete the preparation.

Description

Technical Field

[0001] This invention relates to the field of photoelectrochemical analysis technology, and in particular to a boron-doped Cu x O2 composite bismuth vanadate photoelectrode. Background Technology

[0002] In the face of a escalating global energy crisis and increasingly severe environmental challenges, solar energy, as a green and sustainable renewable energy source, has garnered significant attention in the energy sector due to its cleanliness and abundance, becoming a key research direction for addressing energy and environmental issues. However, the utilization of solar energy still faces numerous challenges, with low conversion efficiency and high storage costs being particularly prominent, severely limiting its large-scale application and promotion. Therefore, developing a technology that can efficiently and cost-effectively convert solar energy into storable chemical energy is of paramount importance for promoting sustainable development in the energy sector.

[0003] Photoelectrochemical (PEC) glucose oxidation technology offers a promising pathway for the efficient utilization of solar energy. This technology not only enables energy conversion through photo-driven redox reactions but also transforms glucose into high-value-added chemicals such as gluconic acid, while simultaneously generating hydrogen energy at the cathode. This process achieves the dual goals of energy conversion and resource optimization, paving a new path for the coordinated development of the energy and chemical industries. The core mechanism of the photoelectrochemical process lies in the generation of photogenerated electron-hole pairs by irradiating the semiconductor surface with light. Under the influence of the electric field at the semiconductor / electrolyte interface, these photogenerated carriers are effectively separated, thereby driving the oxidation reaction of glucose molecules in the solution.

[0004] In recent years, BiVO4 has attracted widespread attention as a promising photoanode material for photoelectrochemical photocells (PECs). BiVO4 possesses many excellent properties, such as a suitable bandgap structure that allows it to effectively absorb visible light, exhibiting excellent visible light response; its raw materials are widely available, inexpensive, and possess good chemical stability. Based on these advantages, BiVO4 is considered one of the most promising candidate materials in the field of photoelectrochemistry. Its maximum photocurrent density is estimated to reach 7.5 mA cm⁻¹. -2 However, in practical applications of glucose oxidation, pure BiVO4 has fallen far short of expectations. This is mainly due to some inherent physical defects, such as limited absorption depth, resulting in insufficient absorption of sunlight; severe recombination of photogenerated carriers, causing a large number of carriers to recombine and annihilate before participating in the reaction, reducing the utilization rate of photogenerated carriers; in addition, the slow surface catalytic kinetics of glucose molecules limits the rate and efficiency of the glucose oxidation reaction.

[0005] Therefore, how to modify BiVO4 through convenient and efficient methods (such as morphology regulation, co-catalyst loading, or heterostructure construction) to enhance its carrier transport capacity and improve its selective oxidation performance of glucose has become the focus of current research in this field. Summary of the Invention

[0006] The purpose of this invention is to provide a boron-doped Cu x This invention relates to an O2-based bismuth vanadate composite photoelectrode to address the aforementioned problems in the background technology. The constructed boron-doped CuxO2 layer serves as a cocatalyst, effectively enhancing the photocatalytic activity of BiVO4, promoting interfacial transport of photogenerated carriers, suppressing electron-hole recombination, and simultaneously strengthening the thermodynamic stability of the photoelectrode, thereby achieving a significant improvement in the overall performance of the photoelectrode.

[0007] To achieve the above objectives, the present invention provides the following technical solution: One of the technical solutions of this invention: providing a boron-doped Cu x The preparation method of O2 composite bismuth vanadate photoelectrode includes the following steps: Potassium iodide and bismuth nitrate were added to a nitric acid solution to obtain solution A; solution A was mixed with a p-benzoquinone solution to obtain electrolyte A; electrolyte A was used as the electrolyte to perform an electrochemical deposition on the surface of the working electrode to obtain a working electrode with a BiOI film deposited on it.

[0008] A solution of acetylacetone vanadium oxide was coated onto the surface of the working electrode on which the BiOI film was deposited, followed by an annealing treatment and then alkaline washing to obtain a bismuth vanadate photoelectrode. Copper nitrate was added to a potassium borate buffer solution to obtain electrolyte B. Using electrolyte B as the electrolyte, a secondary electrochemical deposition was performed on the surface of the bismuth vanadate photoelectrode, followed by a secondary annealing treatment to obtain the boron-doped Cu. x O2 composite bismuth vanadate photoelectrode (B-Cu) x O2 / BiVO4 composite photoelectrode).

[0009] Potassium iodide in this invention is the optimal iodine source for generating BiOI precursor films. The iodine ions it provides are the core component for forming the layered crystal structure of BiOI and are also the key sacrificial template for subsequent in-situ transformation into the target bismuth vanadate crystal form. Other halogen sources (such as potassium chloride) generate bismuth halides (such as BiOCl), which have fundamentally different crystal structures, interlayer spacing, and growth orientations from BiOI, and cannot form uniform and dense precursor films suitable for subsequent annealing reactions. The thermal decomposition temperature of BiOI in this invention is perfectly matched with the annealing temperature window for bismuth vanadate formation. Iodine can be completely volatilized and removed during annealing, leaving no impurities in the bismuth vanadate lattice. Other bismuth halides have excessively high thermal decomposition temperatures, and under conventional annealing conditions, halogens cannot be completely removed, remaining in the product lattice to form impurity energy levels, damaging the target crystal structure and degrading photoelectric performance.

[0010] The vanadium acetylacetonate of this invention is the optimal vanadium source for the process of this invention. It has excellent solubility in common organic solvents, allowing for the preparation of uniform and stable solutions. This enables uniform coating on the surface of the BiOI precursor film, ensuring that the subsequent solid-solid reaction proceeds uniformly across the entire interface. In contrast, inorganic vanadium sources have poor solubility in organic solvents and insufficient wettability to the precursor film. After coating, they are prone to agglomeration and uneven distribution, leading to incomplete reactions and numerous impurity phases in the product. The vanadium valence state of vanadium acetylacetonate can be gradually controlled during annealing, optimizing the nucleation and growth kinetics of bismuth vanadate and obtaining bismuth vanadate with controllable defect concentration and excellent crystallinity. Other vanadium sources have fixed valence states, and their reactivity does not match that of the Bi source, easily generating products with excessive defects or poor crystallinity, significantly reducing the performance of the photoelectrode.

[0011] Preferably, the molar ratio of potassium iodide, bismuth nitrate and p-benzoquinone in electrolyte A is 4:0.4:2.3; and the concentration of potassium iodide in solution A is 0.3~0.5 mol / L.

[0012] Preferably, the pH of the nitric acid solution is 1.65 to 1.75.

[0013] Preferably, the process parameters for the first electrochemical deposition are: initial voltage of -0.1 V and deposition time of 150 s to 200 s.

[0014] Preferably, during the primary electrochemical deposition process, a platinum mesh is used as the counter electrode and an Ag / AgCl electrode is used as the reference electrode.

[0015] Preferably, the working electrode is FTO conductive glass.

[0016] Preferably, the concentration of vanadium acetylacetonate in the vanadium acetylacetonate solution is 0.05~0.2 mol / L.

[0017] Preferably, the coating amount of the vanadium acetylacetonate solution coated on the working electrode surface on which the BiOI thin film is deposited is 40~55 μL·cm. -2 .

[0018] Preferably, the temperature of the first annealing treatment is 440~460℃, the time is 2 h, and the heating rate is 2℃·min. -1 .

[0019] Preferably, the alkaline washing is performed by washing in a 1 M sodium hydroxide solution for 15-25 min.

[0020] Preferably, the concentration of copper ions in the electrolyte B is 0.001~0.003 mol / L, and the concentration of boron ions is 0.4~0.6 mol / L.

[0021] Preferably, the potassium borate buffer solution has a pH of 9.5.

[0022] Preferably, the process parameters for the secondary electrochemical deposition are: initial voltage is open-circuit voltage, and deposition time is 300 s.

[0023] Preferably, during the secondary electrochemical deposition process, the bismuth vanadate photoelectrode is used as the working electrode, the platinum mesh as the counter electrode, and the Ag / AgCl electrode as the reference electrode.

[0024] Preferably, the temperature of the secondary annealing treatment is 200~220℃, and the time is 1~2h.

[0025] Preferably, the solvent for the p-benzoquinone solution is ethanol.

[0026] Preferably, the solvent of the acetylacetone vanadium oxide solution is dimethyl sulfoxide.

[0027] The second technical solution of the present invention: provides a boron-doped Cu obtained according to the above preparation method. x O2 composite bismuth vanadate photoelectrode.

[0028] The third technical solution of the present invention: provides the above-mentioned boron-doped Cu x Application of O2 composite bismuth vanadate photoelectrode in photoelectrochemical glucose oxidation.

[0029] The beneficial technical effects of the present invention are as follows: This invention involves sequentially preparing a BiOI thin film on the surface of a working electrode using an electrochemical deposition process, converting it into a BiVO4 photoelectrode by high-temperature calcination, then forming a B-CuOOH precursor film on the BiVO4 surface via electrochemical deposition, and finally converting it into boron-doped Cu through high-temperature annealing. x O2 co-catalyst layer, finally yielded B-Cu xO2 / BiVO4 composite photoelectrode. The preparation method is simple to operate, highly safe, and uses widely available raw materials, showing good potential for large-scale production.

[0030] The constructed boron-doped CuxO2 layer, acting as a cocatalyst, effectively enhances the photocatalytic activity of BiVO4, promotes interfacial transport of photogenerated carriers, suppresses electron-hole recombination, and simultaneously strengthens the thermodynamic stability of the photoelectrode, thereby significantly improving the overall performance of the photoelectrode. The composite photoelectrode prepared using the electrochemical deposition process defined in this invention is easy to control and possesses advantages such as simplicity and ease of implementation. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a scanning electron microscope image of the BiVO4 photoelectrode in Example 1; Figure 2 B-Cu in Example 1 x Mapping image of O2 / BiVO4 composite photoelectrode under an electron microscope; Figure 3 B-Cu in Example 1 x X-ray photoelectron spectroscopy (XPS) of O2 / BiVO4 composite photoelectrode; Figure 4 The FTO conductive glass, BiVO4 photoelectrode, and B-Cu used in Example 1 are examples of these materials. x X-ray diffraction (XRD) pattern of O2 / BiVO4 composite photoelectrode; Figure 5 B-Cu in Example 1 x Current density versus time curve of O2 / BiVO4 composite photoelectrode; Figure 6 The BiVO4 photoelectrode and B-Fe in Example 1 x O3 / BiVO4 composite photoelectrode, B-Cu x Comparison of linear sweep voltammetry curves of O2 / BiVO4 composite photoelectrode without hole scavenger; Figure 7 The BiVO4 photoelectrode and B-Fe in Example 1 x O3 / BiVO4 composite photoelectrode, B-Cu xComparison of linear sweep voltammetry curves of O2 / BiVO4 composite photoelectrode with hole trapping agent. Detailed Implementation

[0033] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.

[0034] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, are also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0035] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. It should be noted that any aspects of this invention not described in detail are conventional practices in the art and are not the focus of this invention.

[0036] The terms “comprising,” “including,” “having,” “containing,” etc., used in this invention are all open-ended terms, meaning that they include but are not limited to.

[0037] This invention discloses a boron-doped Cu x The preparation method of O2 composite bismuth vanadate photoelectrode includes the following steps: Potassium iodide and bismuth nitrate were added to a nitric acid solution to obtain solution A; solution A was mixed with p-benzoquinone solution to obtain electrolyte A; electrolyte A was used as electrolyte to perform an electrochemical deposition on the surface of the working electrode to obtain a working electrode with a BiOI film deposited on it. A solution of acetylacetone vanadium oxide was coated onto the surface of the working electrode on which the BiOI film was deposited, followed by an annealing treatment and then alkaline washing to obtain a bismuth vanadate (BiVO4) photoelectrode. Copper nitrate was added to a potassium borate buffer solution to obtain electrolyte B. Using electrolyte B as the electrolyte, a secondary electrochemical deposition was performed on the surface of the bismuth vanadate photoelectrode, followed by a secondary annealing treatment to obtain the boron-doped Cu. x O2 composite bismuth vanadate photoelectrode (B-Cu) x O2 / BiVO4 composite photoelectrode).

[0038] Furthermore, the molar ratio of potassium iodide, bismuth nitrate, and p-benzoquinone in electrolyte A is 4:0.4:2.3; and the concentration of potassium iodide in solution A is 0.3~0.5 mol / L.

[0039] Furthermore, the pH of the nitric acid solution is 1.65 to 1.75.

[0040] Furthermore, the process parameters for the first electrochemical deposition are as follows: initial voltage of -0.1 V, sampling interval of 0.1 s, deposition time of 150 s to 200 s, settling time of 0 s, and sensitivity of 1 × 10⁻⁶. -3 A.

[0041] Furthermore, during the electrochemical deposition process, a platinum mesh is used as the counter electrode and an Ag / AgCl electrode is used as the reference electrode.

[0042] Furthermore, the working electrode is FTO conductive glass.

[0043] Furthermore, the concentration of vanadium acetylacetonate in the vanadium acetylacetonate solution is 0.05~0.2 mol / L.

[0044] Furthermore, the coating amount of the vanadium acetylacetonate solution coated on the working electrode surface on which the BiOI thin film is deposited is 40~55 μL·cm. -2 .

[0045] Furthermore, the temperature of the first annealing treatment is 440~460℃, the time is 2 h, and the heating rate is 2℃·min. -1 .

[0046] Furthermore, the alkaline washing involves washing in a 1 M sodium hydroxide solution for 15-25 minutes.

[0047] Furthermore, the concentration of copper ions in electrolyte B is 0.001~0.003 mol / L, and the concentration of boron ions is 0.4~0.6 mol / L.

[0048] Furthermore, the pH value of the potassium borate buffer solution is 9.5.

[0049] Furthermore, the process parameters for the secondary electrochemical deposition are as follows: initial voltage is open-circuit voltage, sampling interval is 0.1 s, deposition time is 300 s, settling time is 0 s, and sensitivity is 1×10⁻⁶. -3 A.

[0050] Furthermore, during the secondary electrochemical deposition process, the bismuth vanadate photoelectrode is used as the working electrode, the platinum mesh as the counter electrode, and the Ag / AgCl electrode as the reference electrode.

[0051] Furthermore, the secondary annealing treatment is performed at a temperature of 200~220℃ for 1~2 hours.

[0052] Furthermore, the solvent for the p-benzoquinone solution is ethanol.

[0053] Furthermore, the solvent for the acetylacetone vanadium oxide solution is dimethyl sulfoxide.

[0054] In the photoelectrode product obtained by this invention, boron-doped Cu... x O2, as a co-catalyst, can effectively improve the catalytic activity of BiVO4, reduce the recombination of photogenerated electron-hole pairs in the BiVO4 photoelectrode, and enhance the thermodynamic stability of BiVO4.

[0055] This invention achieves significantly different technical effects from existing conventional metal doping schemes through targeted improvements in the selection of doping metal elements and their functional properties. For example, compared with the FeB / BiVO4 photoelectrode fabrication method, the LSV current density of the FeB / BiVO4 photoelectrode is 2.8 mA cm⁻¹. -2 The photocurrent density is far lower than that of the photoelectrode of this invention. In contrast, this invention uses copper nitrate as the metal source to prepare B-Cu. x The improved mechanism and performance advantages of O2 / BiVO4 are mainly reflected in the following aspects: On the one hand, the copper-based oxide in the product of this invention can form a pn heterojunction with BiVO4, which has better band matching characteristics and is beneficial to the effective separation and transport of photogenerated carriers at the interface; on the other hand, the inventors found through actual testing that copper ions exhibit better deposition behavior in the potassium borate buffer system, easily forming a uniform and dense B-CuOOH precursor film, which is converted into a highly active B-Cu after annealing. x O2 layer.

[0056] To verify the superiority of the copper element selection in this invention, a single-factor control experiment was further conducted. While maintaining the other preparation conditions identically, only the copper nitrate in electrolyte B was replaced with an equimolar amount of iron nitrate, thus achieving the desired B-Fe alloy. x O3 / BiVO4 electrodes were tested, and their performance was compared. Experimental results show that under AM 1.5G illumination, B-Cu... x The photocurrent density of the O2 / BiVO4 electrode is significantly better than that of the control sample, which confirms that copper doping has an irreplaceable and specific advantage in enhancing the photoelectrochemical performance of BiVO4 photoelectrodes.

[0057] Furthermore, the preparation method includes the following steps: (1) Take 25 mL of nitric acid solution with pH value of 1.6~1.8, add 0.4 mol potassium iodide and 0.04 mol bismuth nitrate pentahydrate, stir thoroughly to obtain solution A; take 10 mL of ethanol, add 0.23 mol p-benzoquinone, sonicate for 3-5 min to obtain solution B; mix solution A and solution B, stir thoroughly to obtain electrolyte A; use electrolyte A as electrolyte, and perform electrochemical deposition on the surface of the working electrode to deposit BiOI crystals to form a thin film, thereby obtaining a working electrode with deposited BiOI thin film; (2) Dissolve 0.2 mol of vanadium acetylacetonate in 2 ml of dimethyl sulfoxide to obtain solution C, and then coat it on the working electrode surface with BiOI film deposited in step (1). Perform an annealing treatment at 440~460℃. After annealing, the sample is washed with sodium hydroxide solution, rinsed with deionized water, and dried to obtain bismuth vanadate photoelectrode. (3) Take 0.5 mol of potassium borate buffer solution (pH=9.5), add 3 mmol of copper nitrate (Cu(NO3)2), and stir until the solution is clear and transparent to obtain electrolyte B; using electrolyte B as electrolyte, perform secondary electrochemical deposition on the surface of the bismuth vanadate photoelectrode by electrochemical method to form a B-CuOOH film on the BiVO4 photoelectrode by deposition. After completion, wash and dry, then perform secondary annealing treatment at 200-220℃, and then wash and dry again to obtain the boron-doped Cu. x O2 composite bismuth vanadate photoelectrode.

[0058] Furthermore, the methods for primary and secondary electrochemical deposition are time-current curve methods.

[0059] The conductivity of the tertiary water used in this invention is no more than 0.50 mS / m (i.e. 5.0 μS / cm) at 25°C, and the resistivity is no less than 0.2 MΩ·cm.

[0060] Unless otherwise specified, the room temperature in this invention is 25±2℃.

[0061] All raw materials used in the following embodiments and comparative examples of the present invention are commercially available products.

[0062] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0063] The technical solution of the present invention will be further illustrated by the following embodiments.

[0064] Example 1 A boron-doped Cu x The preparation method of the O2 composite bismuth vanadate photoelectrode is as follows: Step 1: Fabrication of BiVO4 photoelectrode Take a 20 cm × 15 cm piece of FTO conductive glass, cut it into 2 cm × 3 cm dimensions using a glass cutting table, and then ultrasonically wash it with acetone, ethanol and grade III water for 15 min each. After washing, put it in an oven to dry, and obtain pretreated FTO conductive glass.

[0065] Prepare a nitric acid solution with a pH of 1.7 and transfer it to a brown wide-mouth bottle for storage away from light. Take 25 mL of the above nitric acid solution and place it in a 100 mL beaker. Add 0.01 mol potassium iodide (KI) and 0.001 mol bismuth nitrate pentahydrate (Bi(NO3)3·5H2O), and stir thoroughly until the solution is clear and transparent to obtain solution A. Take 10 mL of anhydrous ethanol and place it in a beaker. Add 0.0023 mol p-benzoquinone and sonicate until the precipitate is completely dissolved to obtain solution B. Mix the above solutions A and B and stir vigorously to dissolve them completely to obtain electrolyte A.

[0066] Using the obtained electrolyte A as the electrolyte, the pretreated FTO conductive glass that has been cleaned and pretreated 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. The electrodeposition conditions were: initial voltage -0.1 V, sampling interval 0.1 s, deposition time 180 s, settling time 0 s, and sensitivity 1 × 10⁻⁶. -3 A. After electrodeposition, a thin film is formed on the surface of the FTO conductive glass. It is then rinsed with three-stage water, dried, and cut into 2cm×1cm dimensions using a glass cutting table to obtain FTO conductive glass with a bismuth-oxygen-iodine film deposited on it, with a deposition thickness of 40mm~60mm.

[0067] FTO conductive glass sheets with a bismuth oxyiodine film deposited on them, each measuring 2 cm × 1 cm, are placed on a high-temperature resistant corundum sheet, with a certain distance (2-4 mm) between the sheets. 1 mL of dimethyl sulfoxide (DMSO) is taken, and 0.2 mol of acetylacetonate vanadyl oxyacetate is added. The mixture is stirred vigorously until no obvious precipitate is obtained, yielding solution C. 100 μL of solution C is taken using a 200 μL pipette and pipetteed at 50 μL·cm⁻¹. -2 The coating amount was determined by uniformly dropping solution C onto the FTO conductive glass surface on which a bismuth-oxygen-iodine film was deposited. Then, a corundum sheet was placed in a muffle furnace and heated at 2°C / min. -1 The temperature was increased to 450℃ at a heating rate and calcined for 2 hours.

[0068] After the muffle furnace cooled naturally to room temperature, the corundum sheet was removed, and the fired FTO conductive glass was placed in a petri dish. 1 M NaOH solution was added, and the glass was soaked for 20 minutes. The resulting product had a complete and uniform surface and was bright yellow. It was then rinsed with tertiary water and dried to obtain a bismuth vanadate photoelectrode (denoted as BiVO4).

[0069] Scanning image of the BiVO4 photoelectrode under an electron microscope as shown below Figure 1 As shown.

[0070] Step 2, B-Cu x Preparation of O2 / BiVO4 composite photoelectrode: Take 50 mL of potassium borate buffer solution (pH=9.5), add solid copper nitrate, and stir until the solution turns pale blue and clear to obtain electrolyte B (the concentration of copper ions in electrolyte B is 0.003 mol / L, and the concentration of boron ions is 0.5 mol / L). Using the obtained electrolyte B as the electrolyte, a secondary electrochemical deposition is performed on the surface of a bismuth vanadate photoelectrode. The specific steps are as follows: using the bismuth vanadate photoelectrode obtained above as the working electrode, a platinum mesh as the counter electrode, and Ag / AgCl as the reference electrode, electrodeposition is performed using the time-current curve method. The electrodeposition conditions are: initial potential of -0.1 V, sampling interval of 0.1 s, deposition time of 300 s, settling time of 0 s, and sensitivity of 1×10⁻⁶. -3 A. After washing and drying, it undergoes a second annealing treatment at 200-220℃ for 1 hour, followed by tertiary water washing and drying to obtain boron-doped Cu. x O2 composite bismuth vanadate photoelectrode (denoted as B-Cu) x O2 / BiVO4).

[0071] Comparative Example 1 The only difference from Example 1 is that the copper nitrate in electrolyte B is replaced with an equimolar amount of ferric nitrate, and the resulting product is denoted as B-Fe. x O3 / BiVO4.

[0072] Effect verification Figure 2 B-Cu in Example 1 x The mapping image of the O2 / BiVO4 composite photoelectrode under an electron microscope proves the successful doping of Cu.

[0073] Figure 3 B-Cu in Example 1 x The X-ray photoelectron spectroscopy (XPS) pattern of the O2 / BiVO4 composite photoelectrode confirms the successful doping of Cu.

[0074] Figure 4 The BiVO4 photoelectrode and B-Cu in Example 1x X-ray diffraction (XRD) pattern of O2 / BiVO4 composite photoelectrode, proving the BiVO4 photoelectrode and B-Cu x Successful fabrication of O2 / BiVO4 composite photoelectrode.

[0075] Figure 5 B-Cu in Example 1 x The current density versus time curve of the O2 / BiVO4 composite photoelectrode; this test is a photoelectrochemical stability test, carried out using a three-electrode system, with the prepared B-Cu... x An O2 / BiVO4 composite photoelectrode was used as the working electrode, a platinum mesh as the counter electrode, and a mercury / mercury oxide electrode as the reference electrode. Tests were conducted under open-circuit voltage-potential conditions. The experiment used AM 1.5G simulated sunlight as the light source. In the graph, the horizontal axis represents the test time, and the vertical axis represents the current density of the photoelectrode. Figure 5 As can be seen from the data, after a long period of continuous illumination testing, B-Cu... x The photocurrent density of the O2 / BiVO4 composite photoelectrode did not decrease significantly, maintaining stable photoelectric response performance, indicating that the B-Cu... x The O2 / BiVO4 composite photoelectrode exhibits excellent photoelectrochemical stability.

[0076] Figure 6 The BiVO4 photoelectrode and B-Fe in Example 1 x O3 / BiVO4 composite photoelectrode, B-Cu x Comparison of linear sweep voltammetric curves of the O2 / BiVO4 composite photoelectrode in the absence of a hole trapping agent; the test employed a three-electrode system, using the prepared series of photoelectrodes as the working electrode, a platinum mesh as the counter electrode, and a mercury / mercuric oxide electrode as the reference electrode, with borate buffer as the supporting electrolyte, and AM 1.5G simulated sunlight as the light source at an intensity of 100 mW·cm⁻¹. -2 .like Figure 6 As shown, the horizontal axis represents the applied voltage, and the vertical axis represents the corresponding photocurrent density. From Figure 6 As can be seen from the test conditions without hole trapping agents, compared with B-Cu x O2 / BiVO4, B-Fe x O3 / BiVO4 composite photoelectrode and pure phase BiVO4 photoelectrode, under the same applied voltage, B-Cu x O2 / BiVO4 composite photoelectrodes can achieve higher photocurrent densities.

[0077] Figure 7 The BiVO4 photoelectrode and B-Fe in Example 1 x O3 / BiVO4 composite photoelectrode, B-Cux Comparison of linear sweep voltammetric curves of the O2 / BiVO4 composite photoelectrode in the presence of a hole trapping agent; the test employed a three-electrode system, using the prepared series of photoelectrodes as the working electrode, a platinum mesh as the counter electrode, and a mercury / mercuric oxide electrode as the reference electrode, with borate buffer as the supporting electrolyte, and AM 1.5G simulated sunlight as the light source at an intensity of 100 mW·cm⁻¹. -2 . Figure 7 As shown, the horizontal axis represents voltage, and the vertical axis represents current density. From Figure 7 As can be seen from the test conditions with hole trapping agent (Na2SO3), compared with B-Cu x O2 / BiVO4, B-Fe x O3 / BiVO4 composite photoelectrode and pure phase BiVO4 photoelectrode, under the same applied voltage, B-Cu x O2 / BiVO4 composite photoelectrodes can achieve higher photocurrent densities.

[0078] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A boron-doped Cu x The method for preparing an O2 composite bismuth vanadate photoelectrode is characterized by, Includes the following steps: Potassium iodide and bismuth nitrate are added to a nitric acid solution to obtain solution A; Solution A is mixed with p-benzoquinone solution to obtain electrolyte A; electrolyte A is used as electrolyte to perform electrochemical deposition on the surface of working electrode to obtain working electrode with BiOI film deposited. A solution of acetylacetone vanadium oxide was coated onto the surface of the working electrode on which the BiOI film was deposited, followed by an annealing treatment and then alkaline washing to obtain a bismuth vanadate photoelectrode. Copper nitrate was added to a potassium borate buffer solution to obtain electrolyte B. Using electrolyte B as the electrolyte, a secondary electrochemical deposition was performed on the surface of the bismuth vanadate photoelectrode, followed by a secondary annealing treatment to obtain the boron-doped Cu. x O2 composite bismuth vanadate photoelectrode.

2. The preparation method according to claim 1, characterized in that, The molar ratio of potassium iodide, bismuth nitrate, and p-benzoquinone in electrolyte A is 4:0.4:2.3; And / or, the concentration of potassium iodide in solution A is 0.3~0.5 mol / L; And / or, the pH of the nitric acid solution is 1.65 to 1.

75.

3. The preparation method according to claim 1, characterized in that, The process parameters for the first electrochemical deposition are: initial voltage of -0.1 V and deposition time of 150 s to 200 s; And / or, the working electrode is FTO conductive glass.

4. The preparation method according to claim 1, characterized in that, The concentration of acetylacetone vanadium oxide in the acetylacetone vanadium oxide solution is 0.05~0.2 mol / L; And / or, the coating amount of the vanadium acetylacetonate solution coated on the working electrode surface on which the BiOI film is deposited is 40~55 μL·cm. -2 .

5. The preparation method according to claim 1, characterized in that, The first annealing treatment was performed at a temperature of 440~460℃ for 2 hours, with a heating rate of 2℃·min. -1 ; And / or, the alkaline washing is washing in a 1 M sodium hydroxide solution for 15-25 min.

6. The preparation method according to claim 1, characterized in that, The concentration of copper ions in electrolyte B is 0.001~0.003 mol / L, and the concentration of boron ions is 0.4~0.6 mol / L. And / or, the pH of the potassium borate buffer solution is 9.

5.

7. The preparation method according to claim 1, characterized in that, The process parameters for the secondary electrochemical deposition are: initial voltage is open-circuit voltage, and deposition time is 300 s.

8. The preparation method according to claim 1, characterized in that, The secondary annealing process is carried out at a temperature of 200~220℃ for 1~2 hours.

9. A boron-doped Cu obtained by the preparation method according to any one of claims 1-8 x O2 composite bismuth vanadate photoelectrode.

10. A boron-doped Cu according to claim 9 x Application of O2 composite bismuth vanadate photoelectrode in photoelectrochemical glucose oxidation.

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