A photocathode with a gas-solid-liquid three-phase interface microenvironment, its preparation method, and its application in photoelectrocatalytic oxygen reduction to produce H2O2.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-23
- Publication Date
- 2026-08-14
AI Technical Summary
另一方面，在常规液/固两相反应体系中，O2的溶解度和扩散速率均极为有限，导致活性位点周围的氧气供给不足，严重制约整体反应速率，并可能诱发副反应
[0015]1、本发明通过简单的溶剂热法，控制反应物配比和溶剂组成，制备了具有二维薄片结构的Zn-TCPP金属有机框架材料，并进一步在其表面负载ZnSe纳米球，构建了具有S型电荷转移路径的ZnSe@Zn-TCPP有机-无机异质结光电极材料，在可见光驱动下，利用光电协同作用高效还原O2生产H2O2。
Smart Images
Figure CN122564597A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of photoelectrocatalytic production of high value-added chemicals, and specifically relates to a photocathode with a gas-solid-liquid three-phase interface microenvironment, its preparation method, and its application in photoelectrocatalytic oxygen reduction to produce H2O2. Background Technology
[0002] Hydrogen peroxide (H2O2) is a novel, highly efficient, and clean energy source and a versatile oxidant. Due to its strong oxidizing properties and environmentally friendly characteristics (its decomposition products are only water and oxygen), it has wide applications in medical and hygiene disinfection, pulp bleaching, wastewater treatment, semiconductor cleaning, and chemical synthesis. While the traditional anthraquinone process is mature and stable, it suffers from several drawbacks, such as complex processes, high equipment investment, high energy consumption, reliance on palladium-based precious metal catalysts leading to high costs, the use of large amounts of organic solvents resulting in severe byproduct pollution, and significant safety hazards during storage and transportation. Therefore, there is an urgent need to develop a greener, safer, more economical, and sustainable new process for H2O2 synthesis.
[0003] As a green alternative, photoelectrochemical (PEC) two-electron oxygen reduction reaction (2e... - The synthesis of H2O2 via the ORR (Organic Reduction Reactor) method is considered highly promising. This process utilizes clean, renewable solar energy as energy input and accelerates the separation of photogenerated carriers with an external electric field, thus significantly improving energy efficiency. Compared to the traditional anthraquinone method, the PEC H2O2 synthesis has significant advantages, including a wide range of raw material sources (water and oxygen) and the ability to operate under mild conditions. In this process, H2O2 is mainly generated through the oxygen reduction reaction at the cathode, and the reaction pathway can be represented as: O2 + 2H+ + +2e - =H2O2, or O2 + via a two-step reduction pathway through the superoxide anion intermediate. e - → O2 - , ·O2 - + 2H + + e - → H2O2. However, utilizing PEC 2e ⁻ The ORR route for H2O2 production still faces many challenges. On the one hand, besides broadening the spectral response of photoelectrocatalytic materials, how to construct heterointerfaces with excellent photogenerated charge separation and transport characteristics to achieve efficient and highly selective H2O2 production remains a key challenge. ⁻The reduction pathway is a key challenge in catalyst design. On the other hand, in conventional liquid / solid two-phase reaction systems, the solubility and diffusion rate of O2 are extremely limited, leading to insufficient oxygen supply around the active sites, severely restricting the overall reaction rate and potentially inducing side reactions. Therefore, designing a novel photoelectrode material that can overcome these challenges and efficiently generate H2O2 is crucial.
[0004] To address the aforementioned challenges, this invention proposes, on the one hand, the construction of an S-type semiconductor heterojunction, which utilizes interface band bending and a built-in electric field to drive the directional migration of photogenerated electrons, thereby suppressing carrier recombination while maintaining a sufficiently negative conduction band potential to facilitate 2e ⁻ Thermodynamic and kinetic selectivity of the ORR path; on the other hand, a photocathode with a gas-solid-liquid three-phase interface microenvironment is constructed, and oxygen is directly transported to the catalytic active site by utilizing a hydrophobic gas diffusion layer, which greatly shortens the oxygen mass transfer path, increases the local oxygen concentration, and inhibits the excessive wetting of the electrode by the electrolyte.
[0005] Based on this, this invention constructs a ZnSe@Zn-TCPP organic-inorganic heterojunction photoelectrocatalytic material with an S-type charge transfer path, and loads it onto a hydrophobic porous carbon felt to construct a photocathode with a gas-solid-liquid three-phase interface. Under the synergistic effect of photoelectrochemicals, this system can achieve efficient production of H2O2. Summary of the Invention
[0006] To solve the above problems, the technical solution of the present invention is as follows: a method for preparing a photocathode with a gas-solid-liquid three-phase interface microenvironment, the method being as follows. Step 1, Preparation of ZnSe: Selenium powder, sodium borohydride and zinc chloride are dissolved in deionized water in sequence and stirred continuously until completely dissolved. The mixed solution is then transferred to an autoclave for hydrothermal reaction. After washing and drying, it is placed in a quartz boat and calcined under an inert atmosphere. After natural cooling, ZnSe powder is obtained. Step 2, Preparation of ZnSe@Zn-TCPP photocathode material: Weigh Zn(NO3)2·6H2O, pyrazine and PVP and dissolve them in a mixed solvent to obtain solution A. Then add ZnSe and disperse it by ultrasonication. Separately dissolve TCPP in a mixed solvent to obtain solution B. Slowly add solution B to solution A containing ZnSe and stir to react, to obtain ZnSe@Zn-TCPP photocathode material; Step 3: Disperse the ZnSe@Zn-TCPP photocathode material in deionized water, add naphthol solution, and after ultrasonic dispersion, uniformly deposit it on carbon felt to obtain a photocathode with a gas-solid-liquid three-phase interface microenvironment.
[0007] In the above-mentioned method for preparing a photocathode with a gas-solid-liquid three-phase interface microenvironment, in step 1, the mass ratio of selenium powder: sodium borohydride: zinc chloride is 4:4:30.
[0008] In the above-mentioned method for preparing a photocathode with a gas-solid-liquid three-phase interface microenvironment, in step 1, the hydrothermal reaction is carried out at 170-190℃ for 5-7 hours. In the above-mentioned method for preparing a photocathode with a gas-solid-liquid three-phase interface microenvironment, step 1 involves calcination at 400°C for 2 hours.
[0009] In the above-mentioned method for preparing a photocathode with a gas-solid-liquid three-phase interface microenvironment, in step 2, the mixed solvent is obtained by mixing DMF and ethanol at a volume ratio of 3:1.
[0010] In the above-mentioned method for preparing a photocathode with a gas-solid-liquid three-phase interface microenvironment, step 2 involves stirring at 80-90°C for 15-17 hours.
[0011] In the above-mentioned method for preparing a photocathode with a gas-solid-liquid three-phase interface microenvironment, in step 2, Zn(NO3)2·6H2O:pyrazine:PVP:ZnSe:TCPP=4.5:0.8:20:0.0065-0.0163:4.
[0012] The photocathode with a gas-solid-liquid three-phase interface microenvironment was prepared according to the above preparation method.
[0013] The aforementioned photocathode with a gas-solid-liquid three-phase interface microenvironment is used in the photoelectrocatalytic oxygen reduction to produce H2O2.
[0014] The above application is carried out as follows: a three-electrode system is constructed using a photocathode with a gas-solid-liquid three-phase interface microenvironment as the working electrode, a platinum sheet as the counter electrode, and Ag / AgCl as the reference electrode. A 0.1 mol / L Na2SO4 aqueous solution is used as the electrolyte, and the pH of the system is adjusted to 1-6 using 10 mol / L HClO4. A 300W xenon lamp is used as the visible light source, and the temperature of the reaction system is controlled at 14-16℃. Oxygen is continuously introduced into the electrolyte under dark conditions, and photoelectrocatalytic preparation of H2O2 is carried out under a bias voltage of -0.5V vs. Ag / AgCl. Beneficial effects of the present invention
[0015] 1. This invention prepares a Zn-TCPP metal-organic framework material with a two-dimensional sheet structure by controlling the reactant ratio and solvent composition through a simple solvothermal method. Furthermore, ZnSe nanospheres are loaded on its surface to construct a ZnSe@Zn-TCPP organic-inorganic heterojunction photoelectrode material with an S-type charge transfer path. Under visible light, the photoelectric synergy is used to efficiently reduce O2 to produce H2O2.
[0016] 2. The photoelectrocatalytic material ZnSe@Zn-TCPP prepared in this invention significantly improves the yield of H2O2 compared to single ZnSe or Zn-TCPP materials. Furthermore, this invention utilizes a hydrophobic carbon felt substrate to construct a gas-solid-liquid three-phase interface microenvironment, enhancing local oxygen concentration and mass transfer efficiency, further increasing H2O2 yield, and significantly improving the performance of photoelectrocatalytic oxygen reduction to hydrogen peroxide synthesis. This contributes to promoting the application of photoelectrocatalysis technology in the field of clean energy production. Attached Figure Description
[0017] Figure 1 SEM images of Zn-TCPP (a), ZnSe (b), and ZnSe@Zn-TCPP (c).
[0018] Figure 2 XRD spectra of Zn-TCPP, ZnSe, and ZnSe@Zn-TCPP.
[0019] Figure 3 XPS full spectrum of Zn-TCPP, ZnSe, and ZnSe@Zn-TCPP photocathode materials.
[0020] Figure 4 LSV curves of Zn-TCPP, ZnSe, and ZnSe@Zn-TCPP photocathodes under different gases.
[0021] Figure 5 The graph shows the comparative test results of H2O2 preparation performance for Zn-TCPP, ZnSe, and ZnSe@Zn-TCPP photocathodes.
[0022] Figure 6 A comparison graph showing the effect of different ZnSe loadings on the production of H2O2 by ZnSe@Zn-TCPP.
[0023] Figure 7 The results show the effect of electrolyte pH on H2O2 yield.
[0024] Figure 8 Hydrophobic angles of carbon paper (a), hydrophobic carbon felt (b), and surface-coated PDMS carbon felt (c) substrates.
[0025] Figure 9The effect of the construction of the gas-solid-liquid three-phase interface on H2O2 production.
[0026] Figure 10 This is a free radical capture experiment.
[0027] Figure 11 A schematic diagram of the possible reaction mechanism for the photocatalytic reduction of oxygen to produce H2O2 using a ZnSe@Zn-TCPP photocathode. Detailed Implementation
[0028] Example 1: Preparation of Zn-TCPP photoelectrode material and photocathode
[0029] Preparation of Zn-TCPP: First, a mixed solvent of DMF and ethanol with a volume ratio of 3:1 was prepared. 45 mg Zn(NO3)2·6H2O, 8 mg pyrazine, and 20 mg PVP were dissolved in 12 mL of the mixed solvent to obtain solution A. 4 mg TCPP was dissolved in 4 mL of the mixed solvent to obtain solution B. Solution B was slowly added dropwise to solution A under vigorous stirring. The mixture was sonicated for 10 minutes, and then stirred in an oil bath at 80℃ for 16 hours. After washing and drying, the Zn-TCPP sample was obtained.
[0030] Preparation of the working electrode: The carbon felt was cut into 2cm×3cm pieces for later use. 5mg Zn-TCPP was dispersed in 0.5 mL of deionized water, 6μL of naphthol solution was added, and after ultrasonic dispersion, it was uniformly deposited on the carbon felt (2cm×2cm). After drying, a uniform catalyst thin layer was formed to obtain the Zn-TCPP photocathode, denoted as Zn-TCPP / CF.
[0031] Example 2: Preparation of ZnSe photoelectrode material and photocathode
[0032] Preparation of ZnSe: 0.8 g selenium powder, 0.8 g sodium borohydride (NaBH4), and 6 g zinc chloride (ZnCl2) were weighed and dissolved sequentially in 30 mL of deionized water, stirring continuously until completely dissolved to ensure sufficient complexation. The mixed solution was then transferred to an autoclave and reacted at 180 °C for 6 h. After washing and drying, the resulting sample was placed in a quartz boat and calcined at 400 °C for 2 h in a tube furnace under argon atmosphere. After natural cooling, ZnSe photocathode material was obtained.
[0033] Preparation of the working electrode: The carbon felt was cut into 2cm×3cm pieces for later use. 5mg of ZnSe photoelectrode material was dispersed in 0.5mL of deionized water, 6μL of naphthol solution was added, and after ultrasonic dispersion, it was uniformly deposited on the carbon felt (2cm×2cm). After drying, a uniform catalyst thin layer was formed to obtain the ZnSe photocathode, denoted as ZnSe / CF.
[0034] Example 3: Fabrication of ZnSe@Zn-TCPP photoelectrode material and photocathode
[0035] Preparation of ZnSe@Zn-TCPP: First, a mixed solvent of DMF and ethanol with a volume ratio of 3:1 was prepared. 4.5 mg Zn(NO3)2·6H2O, 0.8 mg pyrazine, and 20 mg PVP were weighed and dissolved in 12 mL of the mixed solvent to obtain solution A. Then, 0.013 g of ZnSe prepared in Example 2 was added and ultrasonically dispersed. Separately, 4 mg of TCPP was weighed and dissolved in 4 mL of the mixed solvent to obtain solution B. Solution B was slowly added dropwise to solution A containing ZnSe, and the mixture was reacted in an oil bath at 80°C for 16 hours to obtain 20% ZnSe@Zn-TCPP photoelectrode material. By changing the mass of ZnSe added (0.0065 g, 0.0098 g, and 0.0163 g), photoelectrode materials with ZnSe loading ratios of 10%, 15%, and 25% could be obtained.
[0036] Preparation of the working electrode: The carbon felt was cut into 2cm×3cm pieces for later use. 5mg ZnSe@Zn-TCPP was dispersed in 0.5mL of deionized water, and 6μL of naphthol solution was added. After ultrasonic dispersion, the mixture was uniformly deposited on the carbon felt (2cm×2cm). After drying, a uniform catalyst thin layer was formed, denoted as ZnSe@Zn-TCPP / CF.
[0037] Figure 1 In the image, a and b are SEM images of Zn-TCPP and ZnSe, respectively, showing a typical two-dimensional sheet structure and a uniform nanosphere structure. c is an SEM image of ZnSe@Zn-TCPP, indicating that ZnSe nanospheres have been successfully loaded onto the Zn-TCPP surface.
[0038] like Figure 2 As shown, the XRD pattern of the ZnSe@Zn-TCPP photoelectrode material exhibits both characteristic diffraction peaks belonging to the ZnSe crystal phase and characteristic diffraction peaks consistent with those of the Zn-TCPP material. This result indicates that during the composite process, both ZnSe and Zn-TCPP components maintained their original crystal structures, without any significant shift in crystal phase or characteristic peak positions due to inter-component interactions. This strongly confirms the successful construction of the target photoelectrode material.
[0039] Figure 3 XPS full spectra of Zn-TCPP, ZnSe, and ZnSe@Zn-TCPP photoelectrode materials are shown. The results show that characteristic signals of four elements, Zn, Se, C, and N, were detected simultaneously in the full spectrum of ZnSe@Zn-TCPP, further confirming that ZnSe has been successfully loaded onto the surface of Zn-TCPP material. Comparative Example 1
[0040] For comparison, a photocathode based on carbon paper was prepared under the same conditions.
[0041] Example 4: Application of Zn-TCPP / CF, ZnSe / CF, and ZnSe@Zn-TCPP / CF photocathodes in photoelectrocatalytic oxygen reduction to produce H2O2. A three-electrode testing system was constructed using Zn-TCPP / CF, ZnSe / CF, and ZnSe@Zn-TCPP / CF as working electrodes, a platinum sheet (Pt) as the counter electrode, and Ag / AgCl as the reference electrode. A 20 mL, 0.1 mol / L Na₂SO₄ aqueous solution was used as the electrolyte, and the pH was adjusted to 2 with 10 mol / L HClO₄. A 300W xenon lamp (λ > 420 nm) was used as the visible light source, and the temperature of the reaction system was kept constant at approximately 15 °C using a water-circulating condensation system. Before the catalytic reaction, oxygen was continuously bubbled into the electrolyte for 30 min in darkness, and the photoelectrochemical preparation of H₂O₂ was carried out under a bias voltage of -0.5 V (vs. Ag / AgCl). During the experiment, 0.5 mL samples were taken every 15 min, and the concentration of H₂O₂ generated in the system was detected and calculated using the potassium titanium oxalate method.
[0042] 1. LSV curves under different atmospheres like Figure 4 As shown, linear sweep voltammetry (LSV) tests were performed under different atmospheres to determine the applied bias voltage of the photocathode. In an N2-saturated electrolyte solution, no obvious current density response or characteristic reduction peak was observed in any sample, indicating that no significant oxygen reduction reaction occurred on the material surface under an N2 atmosphere. When O2 was introduced, the LSV curves showed obvious reduction characteristic peaks in the potential range of -0.3 to -0.5 V (vs. Ag / AgCl), fully demonstrating that the material has significant oxygen reduction activity in this potential range and can efficiently catalyze the O2 reduction process. In addition, compared with the two monomer materials Zn-TCPP and ZnSe, the ZnSe@Zn-TCPP photoelectrode material exhibited a stronger characteristic reduction peak and a significantly increased current density. This is because the synergistic effect of ZnSe and Zn-TCPP optimizes electron transport and active site exposure, resulting in the strongest reduction peak and the highest current density.
[0043] 2. The effect of different materials on H2O2 production Figure 5The results of comparative tests on the H2O2 generation performance of different materials are shown in the figure. As can be seen from the figure, the H2O2 generation amount of the carbon felt substrate is extremely low. Compared with single ZnSe / CF and Zn-TCPP / CF monomer materials, the ZnSe@Zn-TCPP / CF heterojunction material prepared in this invention exhibits superior H2O2 generation performance, with an H2O2 generation concentration reaching 13.3 mmol·L⁻¹. -1 The efficiency and yield of H2O2 production were 5.8 times that of pure ZnSe and 3.9 times that of pure Zn-TCPP, respectively. These results indicate that constructing a heterojunction structure with ZnSe and Zn-TCPP significantly improves the efficiency and yield of H2O2 production.
[0044] 3. Effect of different ZnSe loadings on H2O2 production like Figure 6 As shown, with the increase of ZnSe loading, the yield of H2O2 by ZnSe@Zn-TCPP photoelectrode material also gradually increases. When the loading is 20%, the amount of H2O2 produced by photoelectrocatalysis is the largest. However, when the ZnSe loading is further increased to 25%, the yield of H2O2 decreases instead.
[0045] 4. Effect of different solution pH values on H2O2 production Figure 7 The effect of electrolyte pH on H2O2 yield is presented. The pH of the electrolyte was adjusted using HClO4 and NaOH, successively set to 2, 4, 5.6, 7, 10, and 12, to systematically investigate the effect of pH on H2O2 production. As shown in the figure, the H2O2 yield reached its peak at pH=2; as the pH gradually increased, the yield continuously decreased. This result indicates that an acidic environment is more conducive to H2O2 formation.
[0046] 5. The impact of the construction of the gas-solid-liquid three-phase interface on H2O2 production The regulation of the electrode surface microenvironment for PEC 2e ⁻ The ORR route is crucial for H2O2 production. Traditional solid-liquid two-phase interfacial microenvironments severely restrict oxygen mass transfer, significantly inhibiting H2O2 production. Constructing a solid-liquid-gas three-phase interfacial microenvironment, with hydrophobic channels, can effectively capture and enrich oxygen, greatly increasing the local oxygen concentration at the interface. This overcomes the mass transfer limitation caused by insufficient dissolved oxygen in conventional two-phase systems. Furthermore, the three-phase interface can expand the effective contact area of the catalyst, allowing active sites to simultaneously and fully contact both oxygen and electrolyte. In addition, a well-designed interfacial microstructure can optimize proton transport channels and accessibility, ensuring a sufficient proton supply while guaranteeing oxygen supply, thus promoting the two-electron oxygen reduction reaction (2e⁻). ⁻ ORR (Orbital-Reduction) is carried out efficiently, thereby significantly improving hydrogen peroxide yield and current efficiency. For example... Figure 8As shown, a solid-liquid two-phase interface microenvironment electrode was constructed using hydrophilic carbon paper (hydrophobic angle = 59.2°) as the substrate, and a three-phase interface microenvironment electrode was constructed using hydrophobic carbon felt (hydrophobic angle = 140.3°) as the substrate. Figure 9 It can be seen that the yield of ZnSe@Zn-TCPP / CF based on carbon felt is significantly better than that of ZnSe@Zn-TCPP / CP based on carbon paper. Further coating of PDMS on the surface of carbon felt to improve its hydrophobicity (hydrophobic angle = 149.4°) to prepare electrodes, with the further improvement of its hydrophobicity, the H2O2 yield was further improved.
[0047] To further investigate the mechanism of photoelectrochemical H2O2 production from the ZnSe@Zn-TCPP photoelectrode material, we conducted capture experiments, using p-benzoquinone (BQ), silver nitrate (AgNO3), isopropanol (IPA), and citric acid as •O2, respectively. - e - •OH and h + Capture agents, such as Figure 10 As shown, inert gas N2 and AgNO3 were introduced respectively to capture e. - Under these conditions, H2O2 formation was almost completely suppressed, demonstrating that H2O2 formation is highly dependent on the presence of O2, and that the oxygen reduction reaction is the key step in H2O2 formation. Regarding the •O2 formation of ZnSe@Zn-TCPP... - and e - After capture, a significant decrease in H2O2 production was observed, indicating that •O2 - and e - They play a crucial role in the ORR process to generate H2O2, and are the main active substances. The system is dominated by a highly selective two-step single-electron ORR reaction mechanism.
[0048] Based on the standard electrode potential for generating active particles (O2 / •O2) - (-0.33 eV vs. NHE)), combined with the capture experiment results and bandgap structure, S-type conduction is considered to be the charge conduction mode of this heterojunction. Figure 11 ).
Claims
1. A method for preparing a photocathode with a gas-solid-liquid three-phase interface microenvironment, characterized in that, The method is as follows: Step 1, Preparation of ZnSe: Selenium powder, sodium borohydride and zinc chloride are dissolved in deionized water in sequence and stirred continuously until completely dissolved. The mixed solution is then transferred to an autoclave for hydrothermal reaction. After washing and drying, it is placed in a quartz boat and calcined under an inert atmosphere. After natural cooling, ZnSe powder is obtained. Step 2, Preparation of ZnSe@Zn-TCPP photocathode material: Weigh Zn(NO3)2·6H2O, pyrazine and PVP and dissolve them in a mixed solvent to obtain solution A. Then add ZnSe and disperse it by ultrasonication. Separately dissolve TCPP in a mixed solvent to obtain solution B. Slowly add solution B to solution A containing ZnSe and stir to react, to obtain ZnSe@Zn-TCPP photocathode material; Step 3: Disperse the ZnSe@Zn-TCPP photocathode material in deionized water, add naphthol solution, and after ultrasonic dispersion, uniformly deposit it on carbon felt to obtain a photocathode with a gas-solid-liquid three-phase interface microenvironment.
2. The method for preparing a photocathode with a gas-solid-liquid three-phase interface microenvironment according to claim 1, characterized in that, In step 1, the mass ratio of selenium powder: sodium borohydride: zinc chloride is 4:4:
30.
3. The method for preparing a photocathode with a gas-solid-liquid three-phase interface microenvironment according to claim 1, characterized in that, In step 1, the hydrothermal reaction is carried out at 170-190℃ for 5-7 hours.
4. The method for preparing a photocathode with a gas-solid-liquid three-phase interface microenvironment according to claim 1, characterized in that, In step 1, the roasting is carried out at 400℃ for 2 hours.
5. The method for preparing a photocathode with a gas-solid-liquid three-phase interface microenvironment according to claim 1, characterized in that, In step 2, the mixed solvent is obtained by mixing DMF and ethanol at a volume ratio of 3:
1.
6. The method for preparing a photocathode with a gas-solid-liquid three-phase interface microenvironment according to claim 1, characterized in that, In step 2, the stirring reaction is carried out at 80-90℃ for 15-17 hours.
7. The method for preparing a photocathode with a gas-solid-liquid three-phase interface microenvironment according to claim 1, characterized in that, In step 2, Zn(NO3)2·6H2O:pyrazine:PVP:ZnSe:TCPP=4.5:0.8:20:0.0065-0.0163:
4.
8. A photocathode with a gas-solid-liquid three-phase interface microenvironment prepared by the preparation method according to any one of claims 1-8.
9. The photocathode with a gas-solid-liquid three-phase interface microenvironment as described in claim 8 is used in the photoelectrocatalytic oxygen reduction to produce H2O2.
10. The application according to claim 9, characterized in that, The method is as follows: a three-electrode system was constructed using a photocathode with a gas-solid-liquid three-phase interface microenvironment as the working electrode, a platinum sheet as the counter electrode, and Ag / AgCl as the reference electrode. A 0.1 mol / L Na2SO4 aqueous solution was used as the electrolyte, and the pH of the system was adjusted to 1-6 using 10 mol / L HClO4. A 300W xenon lamp was used as the visible light source, and the temperature of the reaction system was controlled at 14-16℃. Oxygen was continuously introduced into the electrolyte under dark conditions, and photoelectrocatalytic preparation of H2O2 was carried out under a bias voltage of -0.5V vs. Ag / AgCl.