Ge4se9 composite photocatalyst with sheet structure, preparation method thereof and method for photocatalytic production of hydrogen peroxide

Abstract

The application discloses a Ge4Se9 composite photocatalyst with a sheet structure, a preparation method thereof and a method for photocatalytic production of hydrogen peroxide, and relates to the technical field of photocatalytic materials. The preparation method comprises the following steps: firstly, a sheet structure Ge4Se9 is prepared by using a hydrothermal synthesis method; and then, a cocatalyst is loaded on the sheet structure Ge4Se9 by using a photodeposition method, so as to obtain the sheet structure Ge4Se9 composite photocatalyst. The sheet structure Ge4Se9 composite photocatalyst has outstanding long-wavelength response performance, and breaks through the traditional photocatalytic bottleneck. The sheet structure Ge4Se9 composite photocatalyst has excellent long-wavelength visible light response capability, can still efficiently catalyze a hydrogen peroxide synthesis reaction with water and oxygen as raw materials under the condition of 650nm wavelength light, greatly widens the spectral response range of the catalyst, and significantly improves the solar full-spectrum utilization efficiency.

Description

Technical Field

[0001] This invention relates to the field of photocatalytic materials technology, and in particular to a sheet-like Ge4Se9 composite photocatalyst, its preparation method, and a method for photocatalytic hydrogen peroxide production. Background Technology

[0002] Hydrogen peroxide (H2O2) is a core chemical with both high oxidizing power and environmentally friendly properties, and it has irreplaceable and wide-ranging applications in chemical synthesis, environmental remediation, medical and health care, and energy storage. Currently, the mainstream industrial production process for H2O2 is the anthraquinone process. This process has inherent drawbacks such as high energy consumption, severe organic solvent pollution, numerous byproducts, and a complex production process, making it difficult to meet the current development needs of green chemistry. Artificial photosynthesis technology, driven by solar energy and using water (H2O) and oxygen (O2) as raw materials, synthesizes H2O2 in one step under ambient temperature and pressure conditions. It has significant advantages such as a wide availability of raw materials, mild reaction conditions, and zero pollution, providing an ideal alternative for the sustainable and green production of H2O2.

[0003] The efficient capture and utilization of solar energy is a core factor determining the performance ceiling of photocatalytic H2O2 synthesis systems. However, the lack of photocatalyst materials that simultaneously possess high activity, long-term durability, and efficient solar energy utilization capabilities makes the practical realization of this method still challenging. Developing inorganic photocatalysts with narrow band gaps and long-wavelength light responses is crucial for improving solar energy utilization in H2O2 photosynthesis. Although inorganic materials exhibit higher stability than organic semiconductors in photocatalytic H2O2 production, their light responses are typically limited to wavelengths below 520 nm. Existing materials struggle to effectively capture and utilize the larger proportion of visible light in the long-wavelength region. This deficiency directly leads to low full-spectrum solar energy utilization efficiency, failing to reach the conversion efficiency threshold required for industrial applications.

[0004] Ge4Se9, as a novel layered narrow bandgap semiconductor material, shows great promise for applications in photocatalysis. With an intrinsic bandgap of approximately 1.5–2.0 eV, Ge4Se9 effectively captures most of the visible light in the solar spectrum, fundamentally solving the core problem of narrow photoresponse range in traditional inorganic photocatalysts. Besides its excellent optical properties, Ge4Se9 also possesses advantages such as low toxicity, high cost-effectiveness, abundant reserves, and high chemical stability. However, pure-phase Ge4Se9 still suffers from intrinsic performance defects that limit its actual efficiency in photocatalytic synthesis of H2O2: on the one hand, photogenerated electron-hole pairs in pure-phase Ge4Se9 readily recombine rapidly at the bulk and interface, leading to a significant reduction in the utilization efficiency of photogenerated carriers; on the other hand, the limited density of surface catalytic active sites in pure-phase Ge4Se9 makes it difficult to effectively catalyze the oxygen reduction reaction, thus restricting the kinetics of H2O2 formation. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a sheet-like Ge4Se9 composite photocatalyst and its preparation method. The sheet-like Ge4Se9 composite photocatalyst of this invention can achieve narrow bandgap long-wavelength response, direct visible light / sunlight driving, no sacrificial agent involvement, and hydrogen peroxide production using water and oxygen as the sole raw materials.

[0006] A further technical problem to be solved by the present invention is to provide a method for photocatalytic production of hydrogen peroxide.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A method for preparing a sheet-like Ge4Se9 composite photocatalyst involves first preparing a sheet-like Ge4Se9 using a hydrothermal synthesis method, and then loading a co-catalyst onto the sheet-like Ge4Se9 using a photodeposition method to obtain the sheet-like Ge4Se9 composite photocatalyst.

[0009] The preparation of Ge4Se9 with a plate-like structure using a hydrothermal synthesis method specifically includes the following steps:

[0010] S1: Selenium dioxide, germanium dioxide, deionized water and formic acid are mixed evenly to obtain a mixture; wherein the molar ratio of germanium dioxide to selenium dioxide is 1:2~8, and the molar ratio of germanium dioxide to formic acid is 1:60~260.

[0011] S2: After sealing the mixture, heat it to 140~210℃ and react at a constant temperature for 8~48 hours, then cool it naturally to room temperature to obtain the reaction product;

[0012] S3: The reaction product was subjected to filtration, washing and drying to obtain Ge4Se9 with a plate-like structure.

[0013] The mixing in step S1 is carried out in a reaction vessel with a polytetrafluoroethylene liner.

[0014] The heating in step S2 is specifically carried out by sealing the polytetrafluoroethylene liner tightly before placing it inside the stainless steel outer shell, sealing the stainless steel outer shell, and then placing it in an oven for heating.

[0015] The drying process in step S3 is carried out in a vacuum environment, with a drying temperature of 40℃~60℃ and a drying time of 12~24 hours.

[0016] Among them, the sheet-like Ge4Se9 has an overall sheet-like stacked morphology, with irregular polygonal sheets, relatively flat surfaces, and clear edge contours; the sheet-like Ge4Se9 has an optical band gap of 1.8~2.1 eV, has visible light response capability, and can be directly used for visible light-driven photocatalytic reactions.

[0017] The method of loading the co-catalyst by photodeposition specifically includes the following steps:

[0018] S4: Add the noble metal co-catalyst precursor and the metal oxide co-catalyst precursor together to a phosphate buffer solution dispersion medium with a pH of 6.5 and a concentration of 25 mM, and stir until homogeneous to obtain a uniform dispersion.

[0019] S5: Add the plate-like Ge4Se9 to the above uniform dispersion, continue stirring to form a uniform suspension, and then carry out the photodeposition reaction;

[0020] S6: The photodeposition reaction product obtained by photodeposition reaction is filtered, washed and dried to obtain a sheet-like Ge4Se9 composite photocatalyst.

[0021] In step S4, the noble metal co-catalyst precursor is one or more of rhodium salt, ruthenium salt, iridium salt, gold salt, silver salt, platinum salt, and palladium salt; based on the mass of Ge4Se9 catalyst, the loading of each noble metal co-catalyst is no more than 1%; preferably, the noble metal co-catalyst precursor is one or two of rhodium salt, ruthenium salt, iridium salt, gold salt, silver salt, platinum salt, and palladium salt.

[0022] The metal oxide co-catalyst precursor in step S4 is one or more of iron salt, cobalt salt, manganese salt, and nickel salt; based on the mass of Ge4Se9 catalyst, the loading of each metal oxide co-catalyst is no more than 2%.

[0023] In step S5, the photodeposition reaction temperature is controlled between 5°C and 30°C; a light source with a wavelength greater than 350 nm is used, and the light intensity is 40–200 mW·cm⁻¹. -2The duration of illumination is 0.1 to 4 hours.

[0024] A sheet-like Ge4Se9 composite photocatalyst is prepared using the above-mentioned method for preparing sheet-like Ge4Se9 composite photocatalysts.

[0025] A method for photocatalytic production of hydrogen peroxide, which uses the above-mentioned sheet-like Ge4Se9 composite photocatalyst, wherein the method uses only water and oxygen as reaction raw materials and visible light or sunlight as the sole driving energy source, the concentration of the sheet-like Ge4Se9 composite photocatalyst is 0.1 mg / mL to 5 mg / mL, and the reaction temperature is 5℃ to 30℃.

[0026] In the process of photocatalytic hydrogen peroxide production, oxygen-containing gas is continuously introduced at a flow rate of 0~100 mL / min.

[0027] The beneficial effects of this invention are as follows:

[0028] (1) The sheet-like Ge4Se9 composite photocatalyst of the present invention has outstanding long-wavelength response performance, breaking through the bottleneck of traditional photocatalysis: The sheet-like Ge4Se9 composite photocatalyst of the present invention has excellent long-wavelength visible light response capability. Under 650 nm wavelength light irradiation conditions, it can still catalyze the hydrogen peroxide synthesis reaction using water and oxygen as raw materials with relatively high efficiency, which greatly broadens the spectral response range of the catalyst and significantly improves the full spectrum utilization efficiency of solar energy. It solves the industry pain points of weak long-wavelength response, low visible light utilization rate and limited solar energy conversion of existing photocatalysts.

[0029] (2) Excellent synergistic catalytic performance: By precisely controlling different co-catalysts and the loading ratio of co-catalysts and photodeposition strategies, this invention achieves a tight interfacial bond between the co-catalyst and the Ge4Se9 matrix, effectively suppressing the recombination of photogenerated carriers, significantly improving the carrier separation efficiency and the utilization rate of catalytic active sites, and thus significantly enhancing the intrinsic activity of photocatalytic hydrogen peroxide production.

[0030] (3) The preparation process is highly controllable: It adopts a two-step method combining hydrothermal synthesis and photodeposition. The process steps are simple, the process parameter range is clear, and the batch repeatability is excellent. It does not require complex high-end equipment and can precisely control the microstructure of the catalyst and the loading of the co-catalyst, making it easy to achieve large-scale preparation.

[0031] (4) Good compatibility between raw materials and process costs: The raw materials used in this invention are all commercially available conventional reagents, which are readily available and inexpensive; at the same time, they have the advantages of simple preparation process, short reaction cycle, strong process controllability, convenient operation and low equipment requirements, and have good prospects for industrial application. Attached Figure Description

[0032] Figure 1 This is a SEM image of the sheet-like Ge4Se9 catalyst prepared in Example 1 of this invention; Figure 1 a and Figure 1 b represents the SEM images of Ge4Se9 catalysts with plate-like structures in different regions;

[0033] Figure 2 The UV-Vis diffuse reflectance absorption spectrum of the sheet-like Ge4Se9 catalyst prepared in Example 2 of the present invention is shown.

[0034] Figure 3 This is an EDS-Mapping diagram of the sheet-like Ge4Se9 catalyst prepared in Example 3 of the present invention;

[0035] Figure 4 The XRD pattern of the sheet-like Ge4Se9 catalyst prepared in Example 4 of this invention;

[0036] Figure 5 The image shows the XPS diagram of the sheet-like Ge4Se9 catalyst prepared in Example 4 of this invention; the left image shows the Ge 2p orbitals and the right image shows the Se 3d orbitals.

[0037] Figure 6 The graph shows the hydrogen peroxide production performance test results of the composite photocatalysts prepared in Example 1 and Comparative Examples 1 to 5 of this invention.

[0038] Figure 7 The graph shows the hydrogen peroxide production performance test results of the Ge4Se9 catalysts prepared in Example 4 and Comparative Examples 6 to 10 of this invention under different co-catalyst conditions.

[0039] Figure 8 Apparent quantum efficiency (AQY) for hydrogen peroxide production by the sheet-like Ge4Se9 catalyst prepared in Example 1 of this invention. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0041] This invention provides a method for preparing a sheet-like Ge4Se9 composite photocatalyst, comprising a hydrothermal synthesis step of the sheet-like Ge4Se9 catalyst and a photodeposition loading step of a co-catalyst, the specific operations of which are as follows:

[0042] Part 1: Hydrothermal Synthesis Steps of Ge4Se9 Catalyst

[0043] (1) Analytical grade selenium dioxide, germanium dioxide, deionized water and formic acid were placed in a 200 mL hydrothermal reactor with a polytetrafluoroethylene liner and stirred for 30 minutes until the system was uniformly dispersed; wherein the molar ratio of selenium dioxide to germanium dioxide was 1:2~8; the molar ratio of germanium dioxide to formic acid was 1:60~260, and then deionized water was added, the volume of the mixture accounting for 40%~80% of the volume of the polytetrafluoroethylene liner;

[0044] (2) After the polytetrafluoroethylene liner is tightly sealed, it is placed in the stainless steel shell and the reaction vessel is sealed. It is placed in an oven and heated to 140℃~210℃ and reacted at a constant temperature for 8~48 hours. After the reaction is completed, it is naturally cooled to room temperature.

[0045] (3) Remove the polytetrafluoroethylene liner, filter the reaction product, wash it three times with deionized water and anhydrous ethanol, and then dry it in a vacuum environment at 40~60℃ for 12~24 h to obtain the Ge4Se9 catalyst with a sheet-like structure.

[0046] Part Two: Photodeposition Loading Steps of Ge4Se9 Composite Photocatalyst

[0047] (4) One or more of the following sources are used as precursors for noble metal co-catalysts: Rh source (rhodium salt), Ru source (ruthenium salt), Ir source (iridium salt), Au source (gold salt), Ag source (silver salt), Pt source (platinum salt), Pd source (palladium salt), and Ni source (nickel salt); each precursor corresponds to the elements Rh, Ru, Ir, Au, Ag, Pt, Pd, and Ni, respectively. Based on the mass of the Ge4Se9 substrate catalyst, the mass fraction of each noble metal co-catalyst is 0% to 1%.

[0048] (5) One or more of Fe source (iron salt), Co source (cobalt salt), Mn source (manganese salt) and Ni source (nickel salt) are used as precursors for metal oxide co-catalysts; based on the mass of Ge4Se9 substrate catalyst, the total mass fraction of each metal oxide co-catalyst is 0%~2%.

[0049] (6) The sheet-like Ge4Se9 catalyst prepared in the first part, together with the noble metal co-catalyst precursor in (4) and the metal oxide co-catalyst precursor in (5), are added to the phosphate buffer solution dispersion medium. The components are thoroughly mixed by magnetic stirring to form a uniform and stable suspension. The suspension is transferred to a constant temperature reaction device for photodeposition reaction, and the system parameters are precisely controlled: the concentration of the sheet-like Ge4Se9 catalyst in the phosphate buffer solution dispersion medium is 0.1 mg / mL to 5 mg / mL, the reaction temperature of the photodeposition reaction is 5℃ to 30℃; a light source with a wavelength greater than 350 nm is used, and the reaction temperature is 50 to 200 mW·cm⁻¹. -2 In-situ deposition of the co-catalyst Ge4Se9 was achieved by irradiating with intensity for 0.5 to 4 hours.

[0050] (7) The sample obtained in step (6) is filtered, washed and dried in sequence to obtain a Ge4Se9 composite photocatalyst with a sheet-like structure that has high hydrogen peroxide production activity.

[0051] (8) Add the composite photocatalyst to deionized water (the concentration of the sheet-like Ge4Se9 composite photocatalyst is 0.1 mg / mL to 5 mg / mL), maintain the suspension state with magnetic stirring, and adjust the system temperature to 5℃ to 30℃ using a constant temperature reaction apparatus. During the reaction, oxygen is continuously introduced at a flow rate of 0 to 100 mL / min, and a light source with a wavelength greater than 420 nm is used. The aeration and illumination are started in tandem, and the reaction time is 60 min.

[0052] (9) The concentration of H2O2 generated was determined by colorimetric method: 1 mL of the filtered suspension was taken every 15 min, mixed with 1 mL of 0.02 M potassium titanium oxalate solution, and allowed to stand for 1 minute. The absorbance was measured at a wavelength of 385 nm using a UV spectrophotometer, and the concentration was calculated by combining the hydrogen peroxide standard curve.

[0053] Example 1:

[0054] Part 1: Preparation of Ge4Se9 catalyst.

[0055] (1) Take 0.00214 mol of analytical grade GeO2 and 0.00858 mol of SeO2, with a molar ratio of about 1:4; add 123 mL of deionized water and 17 mL of formic acid (the molar ratio of germanium dioxide to formic acid is 1:210), and place them together in the polytetrafluoroethylene liner of a 200 mL hydrothermal reactor. Stir magnetically for 30 minutes until the system is uniformly dispersed. At this time, the total volume of the mixture is 140 mL, which accounts for 70% of the liner volume.

[0056] (2) After sealing the polytetrafluoroethylene inner liner, put it into the stainless steel outer shell and seal the reaction vessel. Place it in an oven and heat it to 210 °C. React at a constant temperature for 24 hours, and then cool it naturally to room temperature.

[0057] (3) Remove the polytetrafluoroethylene liner, filter the product, wash it four times with deionized water, and then dry it under vacuum at 50°C for 18 hours to obtain a sheet-like Ge4Se9 catalyst. The band gap width is 1.9 eV.

[0058] Part Two: Preparation of Pd-FeCoO x / Ge4Se9 composite photocatalyst.

[0059] (4) Potassium tetrachloropalladium (K2PdCl4), potassium ferricyanide (K3[Fe(CN)6]), and cobalt nitrate (Co(NO3)2) were used as Pd source, Fe source, and Co source, respectively. The mass fractions of each co-catalyst, based on the mass of the Ge4Se9 substrate catalyst, were: 0.4 wt% Pd (K2PdCl4), 0.3 wt% Co (Co(NO3)2), and 0.55 wt% K3[Fe(CN)6], respectively. 0.1 g of the Ge4Se9 substrate catalyst prepared above was added together with the corresponding amounts of the three co-catalyst precursors to 50 mL of phosphate buffer solution (pH=6.5, concentration 25 mM) and magnetically stirred until a uniform suspension was formed.

[0060] (5) Place the suspension in a constant temperature reaction apparatus, adjust the temperature to 5℃, and use a light source with a wavelength greater than 350 nm (light source intensity 100 mW·cm). -2 Irradiation for 2 hours completes the photodeposition reaction.

[0061] (6) The photodeposition reaction products were filtered, washed, and dried sequentially to obtain Pd-FeCoO2 with high hydrogen peroxide production activity. x / Ge4Se9 composite photocatalyst.

[0062] Part 3: Photocatalytic production of hydrogen peroxide.

[0063] (7) Take the Pd-FeCoO prepared above x 0.1 g of Ge4Se9 composite photocatalyst was added to 50 mL of deionized water. The concentration of the Ge4Se9 composite photocatalyst was 2 mg / mL. The mixture was magnetically stirred to maintain suspension. The system temperature was controlled at 5°C using a constant temperature reaction apparatus, with a temperature fluctuation range of ≤±2°C. Pure oxygen was introduced before the reaction, with a cumulative introduction of 4 L over 20 minutes. Oxygen was continuously introduced during the reaction at a flow rate of 50 mL / min. A light source with a wavelength greater than 420 nm was used, and the aeration and illumination were synergistically initiated. The reaction time was 60 min.

[0064] The concentration of H₂O₂ generated was determined by colorimetry: 1 mL of the filtered suspension was taken every 15 min, mixed thoroughly with 1 mL of 0.02 M potassium titanium oxalate solution, and allowed to stand for 1 minute. The absorbance was measured at 385 nm using a UV spectrophotometer, and the concentration was calculated using the hydrogen peroxide standard curve. The test results showed that after 60 min of reaction, the hydrogen peroxide yield was 1066 μmol·h⁻¹. -1 It exhibits good catalytic stability.

[0065] Comparative Example 1

[0066] The first part of Comparative Example 1 is exactly the same as the first part of Example 1.

[0067] The catalyst used in Part 3 is the Ge4Se9 catalyst prepared in Part 1 (i.e., unsupported, denoted as bareGe4Se9), and the rest is the same as in Example 1.

[0068] Comparative Example 2

[0069] The first part of Comparative Example 2 is exactly the same as the first part of Example 1.

[0070] The preparation steps in Part Two are as follows:

[0071] (4) Using palladium chloride (PdCl2) as the Pd source, the co-catalyst was based on the mass of the Ge4Se9 substrate catalyst, with a mass fraction of 1 wt% Pd (PdCl2). Take 0.1 g of the Ge4Se9 catalyst prepared above and add it together with the corresponding amount of catalyst precursor into 50 mL of phosphate buffer solution (pH=6.5, concentration 25 mM), and stir magnetically until a uniform suspension is formed.

[0072] (5) Place the suspension in a constant temperature reaction apparatus, adjust the temperature to 5℃, and use a light source with a wavelength greater than 350 nm (light source intensity 200 mW·cm). -2 Irradiation for 4 hours completes the photodeposition reaction.

[0073] (6) The photodeposition reaction products were filtered, washed and dried in sequence to obtain a Pd / Ge4Se9 composite photocatalyst with high hydrogen peroxide production activity.

[0074] The catalyst used in Part 3 is the Pd / Ge4Se9 composite photocatalyst prepared in Part 2, and the rest is the same as in Example 1.

[0075] Comparative Example 3

[0076] The first part of Comparative Example 3 is exactly the same as the first part of Example 1.

[0077] The preparation steps in Part Two are as follows:

[0078] (4) Using palladium nitrate (Pd(NO3)2) as the Pd source and cobalt chloride (CoCl2) as the Co source, the mass fractions of each co-catalyst, based on the mass of the Ge4Se9 substrate catalyst, were: 0.2 wt% Pd (Pd(NO3)2) and 1 wt% Co (CoCl2). 0.1 g of the Ge4Se9 catalyst prepared above was added together with the corresponding amount of catalyst precursor to 50 mL of phosphate buffer solution (pH=6.5, concentration 25 mM), and magnetically stirred until a uniform suspension was formed.

[0079] (5) Place the suspension in a constant temperature reaction apparatus, adjust the temperature to 15 °C, and use a light source with a wavelength greater than 350 nm (light source intensity 50 mW·cm). -2 Irradiation for 0.1 hours completes the photodeposition reaction.

[0080] (6) The photodeposition reaction products were filtered, washed, and dried sequentially to obtain Pd-CoO with high hydrogen peroxide production activity. x / Ge4Se9 composite photocatalyst.

[0081] The catalyst used in the third part is the Pd-CoO prepared in the second part. x / Ge4Se9 composite photocatalyst, the rest is the same as in Example 1.

[0082] Comparative Example 4

[0083] The first part of Comparative Example 4 is exactly the same as the first part of Example 1.

[0084] The preparation steps in Part Two are as follows:

[0085] (4) Using cobalt sulfate (CoSO4) as the Co source and ferric chloride (FeCl3) as the Fe source, the mass fractions of each co-catalyst, based on the mass of the Ge4Se9 substrate catalyst, were 0.1 wt% Co (CoSO4) and 1 wt% Fe (FeCl3). 0.1 g of the Ge4Se9 catalyst prepared above was added together with the corresponding amount of catalyst precursor to 50 mL of phosphate buffer solution (pH=6.5, concentration 25 mM), and magnetically stirred until a uniform suspension was formed.

[0086] (5) Place the suspension in a constant temperature reaction apparatus, adjust the temperature to 25 °C, and use a light source with a wavelength greater than 350 nm (light source intensity 150 mW·cm). -2 Irradiation for 3 hours completes the photodeposition reaction.

[0087] (6) The photodeposition reaction products were filtered, washed, and dried sequentially to obtain FeCoO2 with high hydrogen peroxide production activity. x / Ge4Se9 composite photocatalyst.

[0088] The catalyst used in the third part is the FeCoO2 prepared in the second part. x / Ge4Se9 composite photocatalyst, the rest is the same as in Example 1.

[0089] Comparative Example 5

[0090] The first part of Comparative Example 5 is exactly the same as the first part of Example 1.

[0091] The preparation steps in Part Two are as follows:

[0092] (4) Using palladium sulfate (PdSO4) as the Pd source and ferric chloride (Fe2(SO4)3) as the Fe source, the mass fractions of each co-catalyst, based on the mass of the Ge4Se9 substrate catalyst, were: 0.1 wt% Pd (PdSO4) and 1 wt% Fe (Fe2(SO4)3). 0.1 g of the Ge4Se9 catalyst prepared above was added together with the corresponding amount of catalyst precursor to 50 mL of phosphate buffer solution (pH=6.5, concentration 25 mM), and magnetically stirred until a uniform suspension was formed.

[0093] (5) Place the suspension in a constant temperature reaction apparatus, adjust the temperature to 30 °C, and use a light source with a wavelength greater than 350 nm (light source intensity 100 mW·cm). -2 Irradiation for 4 hours completes the photodeposition reaction.

[0094] (6) The photodeposition reaction products were filtered, washed, and dried sequentially to obtain Pd-FeO with high hydrogen peroxide production activity. x / Ge4Se9 composite photocatalyst.

[0095] The catalyst used in the third part is the Pd-FeO prepared in the second part. x / Ge4Se9 composite photocatalyst, the rest is the same as in Example 1.

[0096] Example 2

[0097] Part 1: Preparation of Ge4Se9 catalyst.

[0098] (1) Take 0.00214 mol of analytical grade GeO2 and 0.01717 mol of SeO2, with a molar ratio of about 1:8; add 155.2 mL (80%) of deionized water and 4.8 mL (molar ratio of germanium dioxide to formic acid is 1:60) of formic acid, and place them together in the polytetrafluoroethylene liner of a 200 mL hydrothermal reactor. Stir magnetically for 30 minutes until the system is uniformly dispersed. At this time, the total volume of the mixture is 160 mL, which accounts for 80% of the liner volume.

[0099] (2) After sealing the polytetrafluoroethylene inner liner, put it into the stainless steel outer shell and seal the reactor. Place it in an oven and heat it to 210 °C. React at a constant temperature for 48 hours, and then cool it naturally to room temperature.

[0100] (3) Remove the polytetrafluoroethylene liner, filter the product, wash it four times with deionized water, and then dry it under vacuum at 40 °C for 12 hours to obtain a pure phase Ge4Se9 catalyst. The band gap width is 1.8 eV.

[0101] Part Two: Preparation of Pd-FeCoO x / Ge4Se9 composite photocatalyst.

[0102] (4) Potassium tetrachloropalladium, potassium ferricyanide, and cobalt nitrate were used as Pd source, Fe source, and Co source, respectively. The mass fractions of each co-catalyst, based on the mass of the Ge4Se9 substrate catalyst, were: 0.5 wt% Pd (K2PdCl4), 0.2 wt% Co (Co(NO3)2), and 0.35 wt% Fe (K3[Fe(CN)6]). 0.25 g of the Ge4Se9 substrate catalyst prepared above was added together with the corresponding amounts of the three co-catalyst precursors to 50 mL of phosphate buffer solution (pH=6.5, concentration 25 mM) and magnetically stirred until a uniform suspension was formed.

[0103] (5) Place the suspension in a constant temperature reaction apparatus, adjust the temperature to 5 °C, and use a light source with a wavelength greater than 350 nm (light source intensity 200 mW·cm). -2 Irradiation for 2 hours completes the photodeposition reaction.

[0104] (6) The photodeposition reaction products were filtered, washed, and dried sequentially to obtain Pd-FeCoO2 with high hydrogen peroxide production activity. x / Ge4Se9 composite photocatalyst.

[0105] Part 3: Photocatalytic production of hydrogen peroxide.

[0106] (7) Take the Pd-FeCoO prepared above x0.25 g of Ge4Se9 composite photocatalyst was added to 50 mL of deionized water, with a concentration of 5 mg / mL. The mixture was kept in suspension by magnetic stirring. The system temperature was maintained at 5 °C using a constant-temperature reaction apparatus, with temperature fluctuations ≤ ±2 °C. Pure oxygen was introduced before the reaction, with a cumulative introduction of 2 L over 20 minutes. Oxygen was continuously introduced during the reaction at a flow rate of 50 mL / min. A light source with a wavelength greater than 420 nm was used, with aeration and illumination working in tandem. The reaction time was 60 min.

[0107] The concentration of H₂O₂ generated was determined by colorimetry: 1 mL of the filtered suspension was taken every 15 min, mixed thoroughly with 1 mL of 0.02 M potassium titanium oxalate solution, and allowed to stand for 1 minute. The absorbance was measured at 385 nm using a UV spectrophotometer, and the concentration was calculated using the hydrogen peroxide standard curve. The test results showed that after 60 min of reaction, the hydrogen peroxide yield was 877 μmol·h⁻¹. -1 It exhibits good catalytic stability.

[0108] Example 3

[0109] Part 1: Preparation of Ge4Se9 catalyst.

[0110] (1) Take 0.00214 mol of analytical grade GeO2 and 0.0042925 mol of SeO2, with a molar ratio of about 1:2; at the same time, add 59 mL of deionized water and 21 mL of formic acid (the molar ratio of germanium dioxide to formic acid is 1:260) and place them together in the polytetrafluoroethylene liner of a 200 mL hydrothermal reactor. Stir magnetically for 30 minutes until the system is uniformly dispersed. At this time, the total volume of the mixture is 80 mL, accounting for 40% of the liner volume.

[0111] (2) After sealing the polytetrafluoroethylene inner liner, put it into the stainless steel outer shell and seal the reactor. Place it in an oven and heat it to 140 °C. React at a constant temperature for 8 hours, and then cool it naturally to room temperature.

[0112] (3) Remove the polytetrafluoroethylene liner, filter the product, wash it four times with deionized water, and then dry it under vacuum at 60 °C for 24 hours to obtain a pure-phase Ge4Se9 substrate catalyst. The band gap width is 2.1 eV.

[0113] Part Two: Preparation of Pd-FeCoO x / Ge4Se9 composite photocatalyst.

[0114] (4) Potassium tetrachloropalladium, potassium ferricyanide, and cobalt nitrate were used as Pd source, Fe source, and Co source, respectively. The mass fractions of each co-catalyst, based on the mass of the Ge4Se9 substrate catalyst, were: 1 wt% Pd (K2PdCl4), 2 wt% Co (Co(NO3)2), and 2 wt% Fe (K3[Fe(CN)6]). 0.1 g of the Ge4Se9 substrate catalyst prepared above was added together with the corresponding amounts of the three co-catalyst precursors to 50 mL of phosphate buffer solution (pH=6.5, concentration 25 mM), and magnetically stirred until a uniform suspension was formed.

[0115] (5) Place the suspension in a constant temperature reaction apparatus, adjust the temperature to 30 °C, and use a light source with a wavelength greater than 420 nm (light source intensity 40 mW·cm). -2 Irradiation for 0.1 hours completes the photodeposition reaction.

[0116] (6) The photodeposition reaction products were filtered, washed, and dried sequentially to obtain Pd-FeCoO2 with high hydrogen peroxide production activity. x / Ge4Se9 composite photocatalyst.

[0117] Part 3: Photocatalytic production of hydrogen peroxide.

[0118] (7) Take the Pd-FeCoO prepared above x 0.25 g of Ge4Se9 composite photocatalyst was added to 50 mL of deionized water and kept in suspension by magnetic stirring. The system temperature was controlled at 30 °C using a constant-temperature reaction apparatus, with temperature fluctuations ≤ ±2 °C. Pure oxygen was introduced before the reaction, with a cumulative introduction of 2 L over 20 minutes. Oxygen was continuously introduced during the reaction at a flow rate of 20 mL / min. A light source with a wavelength greater than 420 nm was used, and the reaction was initiated in a coordinated manner with aeration and illumination. The reaction time was 60 min.

[0119] The concentration of H₂O₂ generated was determined by colorimetry: 1 mL of the filtered suspension was taken every 15 min, mixed thoroughly with 1 mL of 0.02 M potassium titanium oxalate solution, and allowed to stand for 1 minute. The absorbance was measured at 385 nm using a UV spectrophotometer, and the concentration was calculated using the hydrogen peroxide standard curve. The results showed that after 60 min of reaction, the hydrogen peroxide yield was 353 μmol·h⁻¹. -1 It exhibits good catalytic stability.

[0120] Example 4

[0121] Part 1: Preparation of Ge4Se9 catalyst.

[0122] (1) Take 0.00214 mol of analytical grade GeO2 and 0.00858 mol of SeO2, with a molar ratio of about 1:4; at the same time, add 129.5 mL of deionized water and 10.5 mL of formic acid (the molar ratio of germanium dioxide to formic acid is 1:130) and place them together in the polytetrafluoroethylene liner of a 200 mL hydrothermal reactor. Stir magnetically for 30 minutes until the system is uniformly dispersed. At this time, the total volume of the mixture is 140 mL, which accounts for 70% of the liner volume.

[0123] (2) After sealing the polytetrafluoroethylene inner liner, put it into the stainless steel outer shell and seal the reaction vessel. Place it in an oven and heat it to 200 °C. React at a constant temperature for 24 hours, and then cool it naturally to room temperature.

[0124] (3) Remove the polytetrafluoroethylene liner, filter the product, wash it 4 times with deionized water, and then dry it in a vacuum environment at 50 °C for 18 hours to obtain a pure phase Ge4Se9 catalyst.

[0125] Part Two: Preparation of Pd-FeCoO x / Ge4Se9 composite photocatalyst.

[0126] (4) Using potassium tetrachloropalladium as the Pd source, potassium ferricyanide as the Fe source, and cobalt nitrate as the Co source, the mass fractions of each co-catalyst, based on the mass of the Ge4Se9 substrate catalyst, were: 0.4 wt% Pd (K2PdCl4), 0.2 wt% Co (Co(NO3)2), and 0.2 wt% Fe (K3[Fe(CN)6]). 0.1 g of the Ge4Se9 substrate catalyst prepared above was added together with the corresponding amounts of the three co-catalyst precursors to 50 mL of phosphate buffer solution (pH=6.5, concentration 25 mM), and magnetically stirred until a uniform suspension was formed.

[0127] (5) Place the suspension in a constant temperature reaction apparatus, adjust the temperature to 5 ℃, and use a light source with a wavelength greater than 350 nm (intensity of 100 mW·cm). -2 Irradiation for 2 hours completes the photodeposition reaction.

[0128] (6) The photodeposition reaction products were filtered, washed, and dried sequentially to obtain Pd-FeCoO2 with high hydrogen peroxide production activity. x / Ge4Se9 composite photocatalyst.

[0129] Part 3: Photocatalytic production of hydrogen peroxide.

[0130] (7) Take the Pd-FeCoO prepared above x0.1 g of the Ge4Se9 composite photocatalyst was added to 50 mL of deionized water and kept in suspension by magnetic stirring. The system temperature was controlled at 5 °C using a constant-temperature reaction apparatus, with temperature fluctuations ≤ ±2 °C. Pure oxygen was introduced before the reaction, with a cumulative introduction of 6 L over 20 minutes. Oxygen was continuously introduced during the reaction at a flow rate of 100 mL / min. A light source with a wavelength greater than 550 nm was used, and the aeration and illumination were coordinated for the reaction. The reaction time was 60 min.

[0131] The concentration of H₂O₂ generated was determined by colorimetry: 1 mL of the filtered suspension was taken every 15 min, mixed thoroughly with 1 mL of 0.02 M potassium titanium oxalate solution, and allowed to stand for 1 minute. The absorbance was measured at 385 nm using a UV spectrophotometer, and the concentration was calculated using the hydrogen peroxide standard curve. The results showed that after 60 min of reaction, the hydrogen peroxide yield was 1066 μmol·h⁻¹. -1 It exhibits good catalytic stability.

[0132] Comparative Example 6

[0133] The first part of Comparative Example 6 is exactly the same as the first part of Example 4.

[0134] The preparation steps in Part Two are as follows:

[0135] (4) Using gold chloride (AuCl3), potassium ferricyanide (K3[Fe(CN)6]), and cobalt nitrate (Co(NO3)2) as Au source, Fe source, and Co source, respectively, the co-catalysts were based on the mass of the Ge4Se9 substrate catalyst, with the following mass fractions: 1 wt% Au (AuCl3), 0.4 wt% Co (Co(NO3)2), and 0.8 wt% Fe (K3[Fe(CN)6]). 0.1 g of the Ge4Se9 catalyst prepared above was added together with the corresponding amount of catalyst precursor to 50 mL of phosphate buffer solution (pH=6.5, concentration 25 mM), and magnetically stirred until a uniform suspension was formed.

[0136] (5) Place the suspension in a constant temperature reaction apparatus, adjust the temperature to 10 °C, and use a light source with a wavelength greater than 350 nm (light source intensity 200 mW·cm). -2 Irradiation for 3 hours completes the photodeposition reaction.

[0137] (6) The photodeposition reaction products were filtered, washed, and dried sequentially to obtain Au-FeCoO with high hydrogen peroxide production activity. x / Ge4Se9 composite photocatalyst.

[0138] The catalyst used in the third part is the Au-FeCoO2 prepared in the second part. x / Ge4Se9 composite photocatalyst, the rest is the same as in Example 4.

[0139] Comparative Example 7

[0140] The first part of Comparative Example 7 is exactly the same as the first part of Example 4.

[0141] The preparation steps in Part Two are as follows:

[0142] (4) Sodium rhodium chloride (Na3RhCl6), ferric sulfate (Fe2(SO4)3), and cobalt nitrate (Co(NO3)2) were used as Rh source, Fe source, and Co source, respectively. The co-catalysts were based on the mass of the Ge4Se9 substrate catalyst, with the following mass fractions: 0.5 wt% Rh (Na3RhCl6), 1 wt% Co (Co(NO3)2), and 0.7 wt% Fe (Fe2(SO4)3). 0.1 g of the Ge4Se9 catalyst prepared above was added together with the corresponding amount of catalyst precursor to 50 mL of phosphate buffer solution (pH=6.5, concentration 25 mM), and magnetically stirred until a uniform suspension was formed.

[0143] (5) Place the suspension in a constant temperature reaction apparatus, adjust the temperature to 15 °C, and use a light source with a wavelength greater than 350 nm (light source intensity 150 mW·cm). -2 Irradiation for 2 hours completes the photodeposition reaction.

[0144] (6) The photodeposition reaction products were filtered, washed, and dried sequentially to obtain Rh-FeCoO3 with high hydrogen peroxide production activity. x Ge4Se9 composite photocatalyst.

[0145] The catalyst used in the third part is the Rh-FeCoO2 prepared in the second part. x / Ge4Se9 composite photocatalyst, the rest is the same as in Example 4.

[0146] Comparative Example 8

[0147] The first part of Comparative Example 8 is exactly the same as the first part of Example 4.

[0148] The preparation steps in Part Two are as follows:

[0149] (4) Silver nitrate (AgNO3), iron nitrate (Fe(NO3)3), and cobalt nitrate (Co(NO3)2) were used as Ag source, Fe source, and Co source, respectively. The co-catalysts were based on the mass of the Ge4Se9 substrate catalyst, with the following mass fractions: 0.77 wt% Ag (AgNO3), 1 wt% Co (Co(NO3)2), and 1 wt% Fe (Fe(NO3)3). 0.1 g of the Ge4Se9 catalyst prepared above was added together with the corresponding amount of catalyst precursor to 50 mL of phosphate buffer solution (pH=6.5, concentration 25 mM), and magnetically stirred until a uniform suspension was formed.

[0150] (5) Place the suspension in a constant temperature reaction apparatus, adjust the temperature to 10 °C, and use a light source with a wavelength greater than 350 nm (light source intensity 120 mW·cm). -2 Irradiate for 1 hour to complete the photodeposition reaction.

[0151] (6) The photodeposition reaction product was filtered, washed and dried sequentially to obtain Ag-FeCoO with high hydrogen peroxide production activity. x / Ge4Se9 composite photocatalyst.

[0152] The catalyst used in the third part is the Ag-FeCoO2 prepared in the second part. x / Ge4Se9 composite photocatalyst, the rest is the same as in Example 4.

[0153] Comparative Example 9

[0154] The first part of Comparative Example 9 is exactly the same as the first part of Example 4.

[0155] The preparation steps in Part Two are as follows:

[0156] (4) Sodium chloroplatinate (Na2PtCl6), potassium ferricyanide (K3[Fe(CN)6]), and cobalt nitrate (Co(NO3)2) were used as Pt source, Fe source, and Co source, respectively. The co-catalysts were based on the mass of the Ge4Se9 substrate catalyst, with the following mass fractions: 0.5 wt% Pt (Na2PtCl6), 1 wt% Co (Co(NO3)2), and 2 wt% Fe (Fe2(SO4)3). 0.1 g of the Ge4Se9 catalyst prepared above was added together with the corresponding amount of catalyst precursor to 50 mL of phosphate buffer solution (pH=6.5, concentration 25 mM), and magnetically stirred until a uniform suspension was formed.

[0157] (5) Place the suspension in a constant temperature reaction apparatus, adjust the temperature to 10 °C, and use a light source with a wavelength greater than 350 nm (light source intensity 200 mW·cm). -2Irradiation for 4 hours completes the photodeposition reaction.

[0158] (6) The photodeposition reaction products were filtered, washed and dried sequentially to obtain Pt-FeCoO with high hydrogen peroxide production activity. x / Ge4Se9 composite photocatalyst.

[0159] The catalyst used in the third part is the Pt-FeCoO2 prepared in the second part. x / Ge4Se9 composite photocatalyst, the rest is the same as in Example 4.

[0160] Comparative Example 10

[0161] The first part of Comparative Example 10 is exactly the same as the first part of Example 4.

[0162] The preparation steps in Part Two are as follows:

[0163] (4) Ruthenium chloride (RuCl3), ferric sulfate (Fe2(SO4)3), and cobalt sulfate (CoSO4) were used as Ru source, Fe source, and Co source, respectively. The co-catalysts were based on the mass of the Ge4Se9 substrate catalyst, with the following mass fractions: 0.5 wt% Ru (RuCl3), 2 wt% Co (CoSO4), and 0.7 wt% Fe (Fe2(SO4)3). 0.1 g of the Ge4Se9 catalyst prepared above was added together with the corresponding amount of catalyst precursor to 50 mL of phosphate buffer solution (pH=6.5, concentration 25 mM), and magnetically stirred until a uniform suspension was formed.

[0164] (5) Place the suspension in a constant temperature reaction apparatus, adjust the temperature to 20 °C, and use a light source with a wavelength greater than 350 nm (light source intensity 170 mW·cm). -2 Irradiation for 2 hours completes the photodeposition reaction.

[0165] (6) The photodeposition reaction products were filtered, washed, and dried sequentially to obtain Ru-FeCoO₂ with high hydrogen peroxide production activity. x / Ge4Se9 composite photocatalyst.

[0166] The catalyst used in the third part is the Ru-FeCoO2 prepared in the second part. x / Ge4Se9 composite photocatalyst, the rest is the same as in Example 4.

[0167] Performance testing:

[0168] Figure 1 This is a SEM image of the sheet-like Ge4Se9 catalyst prepared in Example 1 of this invention; Figure 1In the figures, a and b are SEM images of different regions of the sheet-like Ge4Se9 catalyst prepared in Example 1 of this invention. Figure 1 It can be seen that the catalysts all exhibit a thin-plate stacked morphology, with irregular polygonal sheets, relatively flat surfaces, and clear edge contours. This morphology can shorten the carrier migration path and increase the specific surface area, which is beneficial to improving photocatalytic performance.

[0169] Figure 2 The image shows the UV-Vis diffuse reflectance absorption spectrum of the sheet-like Ge4Se9 catalyst prepared in Example 2 of this invention. Figure 2 The results show that the sample exhibits strong absorption in the 200-600 nm ultraviolet-visible region, reaching an absorption peak near 400 nm. Subsequently, the absorption intensity rapidly decreases, with an absorption cutoff wavelength of 630 nm. Based on this, the estimated optical bandgap is approximately 1.97 eV, confirming the sample's visible light response capability. In the 800-2000 nm near-infrared region, the sample absorption approaches zero.

[0170] Figure 3 This is an EDS-Mapping image of the sheet-like Ge4Se9 catalyst prepared in Example 3 of this invention. From... Figure 3 It can be seen that the Ge and Se elemental signals are uniformly distributed and perfectly match the particle profile, confirming that the micro-region is a single-phase Ge4Se9.

[0171] Figure 4 This is the XRD pattern of the sheet-like Ge4Se9 catalyst prepared in Example 4 of this invention. Figure 4 From the perspective of spectral matching, all characteristic diffraction peaks of the sample perfectly match the peak positions of standard Ge4Se9, and there are no obvious impurity peaks or amorphous diffuse peaks, confirming that the sample is a high-purity single-phase crystalline Ge4Se9. The diffraction peaks have good sharpness, indicating that the sample has good crystallinity, with regular atomic arrangement and low defect density inside the crystal.

[0172] Figure 5 This is an XPS image of the sheet-like Ge4Se9 catalyst prepared in Example 4 of this invention. From... Figure 5 It can be seen that the spectrum, after fitting, only shows Ge. 4+ Characteristic peaks (binding energy ~1220 eV), no Ge 2+ The presence of impurity peaks in elemental Ge indicates that Ge in the sample is primarily coordinated with Se in the +4 valence state, which perfectly matches the structural and chemical characteristics of Ge4Se9. Peak fitting yielded Se... 2- (Se 3d) 3 / 2 、Se 3d 5 / 2 ) and Se2 2-The characteristic signal. This result reflects the intrinsic structure of Ge4Se9 constrained by stoichiometry: because the Ge:Se ratio of 4:9 cannot be determined solely by Ge... 4+ With isolated Se 2- The tetrahedral coordination satisfies charge balance, and Se2 will naturally form in the system. 2- Diselenium ions (existing in the form of Ge-Se-Se-Ge bridging bonds) are used to adapt to stoichiometry and structural stability.

[0173] Figure 6 The graph shows the hydrogen peroxide production performance test results of the composite photocatalysts prepared in Example 1 and Comparative Examples 1 to 5 of the present invention, i.e., the kinetic curves of catalytic generation of hydrogen peroxide (H2O2) under visible light. Figure 6 As can be seen, the bare Ge4Se9 sample (grey curve) in Comparative Example 1 exhibits the weakest H2O2 production activity, with an H2O2 concentration of only about 350 μM at 60 min. When a co-catalyst is introduced, the activities of all modified samples obtained in Comparative Examples 2 to 5 and Example 1 are significantly higher than those of bare Ge4Se9: Specifically, the Pd / Ge4Se9 sample in Comparative Example 2 (green curve) shows an H2O2 production concentration of approximately 480 μM at 60 min, which is attributed to Pd's efficient capture of photogenerated electrons as a noble metal co-catalyst, promoting O2 adsorption and activation; the FeCoO2 sample in Comparative Example 4... x The activity of / Ge4Se9 (purple curve) increased to approximately 490 μM, reflecting the trapping and transfer effect of transition metal oxides on holes, which can further suppress charge recombination; among them, Pd-FeCoO3 in Example 1 showed the best performance. x The sample modified with the three-component Ge4Se9 cocatalyst (red curve) showed an H2O2 generation concentration of nearly 1000 μM at 60 min through synergistic electron-hole separation, which is approximately 2.9 times that of bare Ge4Se9 and significantly superior to other cocatalyst systems. This result fully demonstrates the synergistic effect of the multi-component cocatalyst.

[0174] Figure 7 The graph shows the kinetic curves and hydrogen peroxide production performance test results of the different co-catalysts Ge4Se9 composite photocatalysts prepared in Example 4 and Comparative Examples 6 to 10 of this invention, catalyzing the production of hydrogen peroxide (H2O2) under visible light. x The Ge4Se9 composite photocatalyst (blue curve) exhibited the strongest H2O2 production activity, with an H2O2 concentration of approximately 1066 μM at 60 min. Comparative Examples 6 to 10 compared Au, Rh, Ru, Ag, and Pt as noble metal co-catalysts with FeCoO2. xThe results for co-catalysts. This result reflects the performance differences caused by the different work functions of different metals and the catalyst host.

[0175] Figure 8 The apparent quantum efficiency (AQY) for hydrogen peroxide production by the sheet-like Ge4Se9 catalyst prepared in Example 1 of this invention is calculated. Figure 8 As shown, its apparent quantum efficiency curve is highly consistent with the optical absorption of Ge4Se9, confirming that the synthesis process is driven by intrinsic interband excitation. Notably, the AQY reaches 10.9% at 420 nm and remains as high as 1.8% even at 650 nm.

[0176] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention. The above embodiments are provided only for the purpose of describing the present invention and are not intended to limit the present invention. Parts not described in detail in this specification are well-known in the art and are not intended to limit the scope of the present invention. The scope of the present invention is defined by the appended claims. All equivalent substitutions and modifications made without departing from the spirit and principle of the present invention should be covered within the scope of the present invention.

Claims

1. A method for preparing a sheet-like Ge4Se9 composite photocatalyst, characterized in that: The preparation method first uses a hydrothermal synthesis method to prepare a sheet-like Ge4Se9, and then uses a photodeposition method to load a co-catalyst on the sheet-like Ge4Se9 to obtain a sheet-like Ge4Se9 composite photocatalyst.

2. The method for preparing the sheet-like Ge4Se9 composite photocatalyst according to claim 1, characterized in that, The preparation of plate-like Ge4Se9 using a hydrothermal synthesis method includes the following steps: S1: Selenium dioxide, germanium dioxide, deionized water and formic acid are mixed evenly to obtain a mixture; wherein the molar ratio of germanium dioxide to selenium dioxide is 1:2~8, and the molar ratio of germanium dioxide to formic acid is 1:60~260. S2: After sealing the mixture, heat it to 140~210℃ and react at a constant temperature for 8~48 hours, then cool it naturally to room temperature to obtain the reaction product; S3: The reaction product was subjected to filtration, washing and drying to obtain Ge4Se9 with a plate-like structure.

3. The method for preparing the sheet-like Ge4Se9 composite photocatalyst according to claim 2, characterized in that, The homogenization in step S1 is carried out in a reaction vessel with a polytetrafluoroethylene liner; The heating in step S2 is specifically carried out by sealing the polytetrafluoroethylene liner tightly before placing it inside the stainless steel outer shell, sealing the stainless steel outer shell, and then placing it in an oven for heating. The drying process in step S3 is carried out in a vacuum environment, with a drying temperature of 40℃~60℃ and a drying time of 12~24 hours.

4. The method for preparing the sheet-like Ge4Se9 composite photocatalyst according to claim 1, characterized in that, The sheet-like structure of Ge4Se9 exhibits an overall stacked morphology of thin sheets, with irregular polygonal layers; the optical band gap of the sheet-like structure of Ge4Se9 is 1.8~2.1 eV.

5. The method for preparing the sheet-like Ge4Se9 composite photocatalyst according to claim 2, characterized in that, The process of loading a cocatalyst via photodeposition includes the following steps: S4: Add the noble metal co-catalyst precursor and the metal oxide co-catalyst precursor together to a phosphate buffer solution dispersion medium with a pH of 6.5 and a concentration of 25 mM, and stir until homogeneous to obtain a uniform dispersion. S5: Add the plate-like Ge4Se9 to the above uniform dispersion, continue stirring to form a uniform suspension, and then carry out the photodeposition reaction; S6: The photodeposition reaction product obtained by photodeposition reaction is filtered, washed and dried to obtain a sheet-like Ge4Se9 composite photocatalyst.

6. The method for preparing the sheet-like Ge4Se9 composite photocatalyst according to claim 5, characterized in that, The noble metal co-catalyst precursor in step S4 is one or more of the following: rhodium salt, ruthenium salt, iridium salt, gold salt, silver salt, platinum salt, and palladium salt; based on the mass of the Ge4Se9 catalyst, the loading of each noble metal co-catalyst is no more than 1%; The metal oxide co-catalyst precursor in step S4 is one or more of iron salt, cobalt salt, manganese salt, and nickel salt; based on the mass of Ge4Se9 catalyst, the loading of the metal oxide co-catalyst is no more than 2%.

7. The method for preparing the sheet-like Ge4Se9 composite photocatalyst according to claim 5, characterized in that, In step S5, the photodeposition reaction temperature is controlled between 5°C and 30°C; a light source with a wavelength greater than 350 nm is used, and the light intensity is 40–200 mW·cm. -2 The duration of illumination is 0.1 to 4 hours.

8. A sheet-like Ge4Se9 composite photocatalyst, characterized in that, It was prepared using the method described in any one of claims 1 to 7 for the preparation of the sheet-like Ge4Se9 composite photocatalyst.

9. A method for photocatalytic production of hydrogen peroxide, characterized in that, The method of photocatalyzing hydrogen peroxide using the sheet-like Ge4Se9 composite photocatalyst as described in claim 8 uses only water and oxygen as reaction raw materials and visible light or sunlight as the sole driving energy source. The concentration of the sheet-like Ge4Se9 composite photocatalyst is 0.1 mg / mL to 5 mg / mL, and the reaction temperature is 5℃ to 30℃.

10. The method for photocatalytic hydrogen peroxide production according to claim 9, characterized in that, During the photocatalytic hydrogen peroxide production process, oxygen-containing gas is continuously introduced at a flow rate of 0~100 mL / min.

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