A z-type zn tcpp / zis heterojunction catalyst and a preparation method and application thereof

Abstract

This invention discloses a Z-type ZnTCPP / ZIS heterojunction catalyst, its preparation method, and its application, belonging to the field of photocatalysis technology. The process includes the following steps: Step S1, synthesizing a zinc porphyrin metal-organic framework (Zn-TCPP); Step S2, dissolving Zn-TCPP, zinc salt, indium salt, and a sulfur source in water, stirring until homogeneous, and then performing a solvothermal reaction; Step S3, after the reaction is complete, cooling to room temperature, centrifuging, washing, and drying to obtain the Z-type ZnTCPP / ZIS heterojunction catalyst. Photogenerated electrons on the ZnIn2S4 conduction band recombine with photogenerated holes on the ZnTCPP valence band at the interface, while the electrons retained on the ZnTCPP conduction band and the holes on the ZnIn2S4 valence band possess strong reducing and oxidizing abilities, respectively. This forms a built-in electric field from ZnTCPP to ZnIn2S4, and the unique charge transfer path promotes the spatial separation of photogenerated carriers, effectively suppressing bulk recombination of electron-hole pairs, and significantly improving charge separation efficiency and photocatalytic activity.

Description

Technical Field

[0001] This invention relates to the field of photocatalysis technology, specifically to a Z-type ZnTCPP / ZIS heterojunction catalyst, its preparation method, and its application. Background Technology

[0002] Hydrogen peroxide (H2O2), as an important green oxidant and energy carrier, has wide applications in environmental protection, chemical industry, medicine, and energy. Traditional industrial anthraquinone processes for H2O2 production suffer from problems such as complex processes, high energy consumption, and significant pollution. Photocatalysis, utilizing solar energy to directly convert water and oxygen into H2O2, represents a promising green synthetic route. The core of this technology lies in developing efficient, stable photocatalysts that respond in the visible light region.

[0003] Currently, common materials used for photocatalytic H2O2 production include TiO2, g C3N4, MOFs, and ternary sulfides (such as ZnIn2S4) are among the catalytic agents. ZnIn2S4 (ZIS) has a suitable visible light absorption band gap, but its fast photogenerated carrier recombination rate limits its catalytic efficiency.

[0004] Furthermore, most photocatalytic H2O2 production systems rely on organic sacrificial agents (such as alcohols) to consume holes and promote the reaction. This not only increases costs but may also trigger side reactions that lead to a decrease in H2O2 selectivity. Developing efficient photocatalytic systems that do not require sacrificial agents and directly use water and oxygen as raw materials has significant practical implications and application value. Summary of the Invention

[0005] To address or partially address the problems existing in related technologies, this invention provides a Z-type ZnTCPP / ZIS heterojunction catalyst, its preparation method, and its application. By compositing ZnTCPP with ZnIn2S4 nanosheets to form a Z-type ZnTCPP / ZIS heterojunction catalyst, this catalyst achieves efficient and stable visible light-driven hydrogen peroxide production without the use of sacrificial agents.

[0006] To achieve the above objectives, the technical solution of this invention is as follows: A method for preparing a Z-type ZnTCPP / ZIS heterojunction catalyst is provided, the innovation of which lies in the following steps: Step S1: Synthesis of zinc porphyrin metal-organic framework Zn-TCPP; Step S2: Dissolve Zn-TCPP, zinc salt, indium salt and sulfur source in water, stir well and then carry out a solvothermal reaction; Step S3: After the reaction is complete, cool to room temperature, centrifuge, wash, and dry to obtain the Z-type ZnTCPP / ZIS heterojunction catalyst.

[0007] Preferably, the synthesis process of Zn-TCPP in step S1 is as follows: first, 5, 10, 15, 20 4(4) Carboxyphenyl)porphyrin and zinc nitrate hexahydrate dissolve sequentially in N,N Benzoic acid was added as a regulator to dimethylformamide, and the mixture was stirred at 80-100℃ for 4-5 hours. The precipitate was collected by centrifugation, washed, and dried to obtain Zn. TCPP.

[0008] Preferably, each 5 ml of N,N In dimethylformamide, 5, 10, 15, 20 4(4) The molar amount of carboxyphenyl porphyrin added was 0.0169 - 0.0508 mmol, the molar amount of zinc nitrate hexahydrate added was 0.4225 - 1.27 mmol, and the amount of benzoic acid added was 0.10 - 0.14 g; After adding benzoic acid, then add N,N Dimethylformamide, followed by N,N The amount of dimethylformamide was 4-4.4 times that of before.

[0009] Preferably, the washing conditions are: washing with ethanol 3 to 5 times; the drying conditions are: vacuum drying at 60 to 80°C.

[0010] Preferably, in step S2, the zinc salt is zinc acetate dihydrate, the indium salt is indium chloride, and the sulfur source is thioacetamide.

[0011] Preferably, in step S2, the molar ratio of Zn-TCPP, zinc salt, indium salt and sulfur source is (0.004-0.04):0.4:0.8:1.6; and the amount of Zn-TCPP added per 30 mL of water is 5-30 mg.

[0012] Preferably, in step S2, the reaction temperature of the solvothermal reaction is 180~200℃, and the reaction time is 24~26h.

[0013] Preferably, in step S3, the washing conditions are: first wash with deionized water 3 to 5 times, then wash with ethanol 3 to 5 times; the drying conditions are: vacuum drying at 60 to 80°C overnight.

[0014] The innovative feature of the Z-type ZnTCPP / ZIS heterojunction catalyst prepared according to the above preparation method is that the catalyst is a hierarchical heterostructure assembled from Zn-TCPP and ZnIn2S4 nanosheets, and the mass percentage of Zn-TCPP in the catalyst is 3-16 wt%.

[0015] The innovation of the above-mentioned Z-type ZnTCPP / ZIS heterojunction catalyst in photocatalytic hydrogen peroxide production lies in the fact that the catalyst is dispersed in an oxygen-saturated aqueous solution, and the reaction of water and oxygen is catalyzed to produce hydrogen peroxide under visible light irradiation.

[0016] This invention provides a Z-type ZnTCPP / ZIS heterojunction catalyst, its preparation method, and its application, which have the following beneficial effects: (1) The Z-type ZnTCPP / ZIS heterojunction catalyst obtained by the preparation method of the present invention has a two-dimensional layered Zn TCPP surfaces are formed by solvothermal growth of ZnIn2S4 nanosheets, resulting in a tight interfacial contact and a stacked sheet structure. This heterojunction follows a Z-type charge transfer mechanism: under illumination, photogenerated electrons in the conduction band of ZnIn2S4 react with Zn... Photogenerated holes in the TCPP valence band recombine at the interface, while those retained in Zn Electrons in the TCPP conduction band and holes in the ZnIn2S4 valence band possess strong reducing and oxidizing abilities, respectively. This leads to the formation of Zn... TCPP points to the built-in electric field of ZnIn2S4, and its unique charge transfer path promotes the spatial separation of photogenerated carriers and effectively suppresses electrons. Bulk recombination of hole pairs significantly improves charge separation efficiency and photocatalytic activity.

[0017] (2) Under the driving force of the built-in electric field at the interface, the photogenerated electrons in the conduction band of ZnIn2S4 recombine with the holes in the valence band of Zn-TCPP, effectively suppressing carrier bulk recombination, while retaining electrons with strong reducing ability in the conduction band of Zn-TCPP. These long-lived electrons reduce O2 to ·O2 through the two-electron oxygen reduction pathway. - It generates H2O2, achieving efficient conversion of light energy into chemical energy. Therefore, the Z-type ZnTCPP / ZIS heterojunction catalyst of this invention has a high apparent quantum yield (AQY).

[0018] (3) ZT / ZIS prepared in this invention The heterojunction catalyst exhibits high H2O2 yield under pure water, visible light irradiation, and without any sacrificial agents, demonstrating superior performance compared to other photocatalysts. The catalyst maintains stable activity after multiple cycles and maintains high H2O2 yields in various water sources (tap water, lake water, and seawater), showcasing excellent potential for practical applications. Attached Figure Description

[0019] Figure 1 The XRD patterns are of the catalysts prepared in Examples 1-4 and Comparative Examples 1-2 of this invention.

[0020] Figure 2 FT of the catalysts prepared in Examples 1-4 and Comparative Examples 1-2 of the present invention IR spectrum.

[0021] Figure 3 The SEM spectra of the catalysts prepared in Example 1 and Comparative Examples 1-2 of this invention are shown.

[0022] Figure 4 TEM image of the ZT / ZIS-3 catalyst prepared for Example 1 of the present invention.

[0023] Figure 5 The image shows a TEM-Mapping of the ZT / ZIS-3 catalyst prepared in Example 1 of this invention.

[0024] Figure 6 UV of the catalysts prepared in Examples 1-4 and Comparative Examples 1-2 of the present invention vis DRS diagram.

[0025] Figure 7 The above are It curves of the catalysts prepared in Examples 1-4 and Comparative Examples 1-2 of the present invention.

[0026] Figure 8 The graph shows the H2O2 production of the catalysts prepared in Examples 1-4 and Comparative Examples 1-2 of this invention under visible light irradiation (λ>420 nm).

[0027] Figure 9 The graph shows the heterojunction cycle stability test of the ZT / ZIS-3 catalyst prepared in Example 1 of the present invention.

[0028] Figure 10 The image shows the XRD pattern of the heterojunction of the ZT / ZIS-3 catalyst prepared in Example 1 of this invention after cycling.

[0029] Figure 11 The graph shows the H2O2 production of the heterojunction of the ZT / ZIS-3 catalyst prepared in Example 1 of this invention from different water sources.

[0030] Figure 12 ZT / ZIS prepared in Example 1 for free radical capture experiments 3. Effect of heterojunction photocatalytic H2O2 production performance. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings, but the scope of protection of the present invention is not limited to the content described.

[0032] Example 1 This embodiment provides a method for preparing a Z-type ZnTCPP / ZIS heterojunction catalyst, including the following steps: (1) Weigh 0.04 mmol (approximately 31.6 mg) of 5,10,15,20-tetra(4-carboxyphenyl)porphyrin (TCPP) and place it in a 50 mL round-bottom flask. Add 5 mL of N,N-dimethylformamide (DMF) to the flask and sonicate it for 4 min to initially disperse it. Then, add 1 mmol (approximately 297.5 mg) of zinc nitrate hexahydrate and 0.12 g of benzoic acid. Add another 21 mL of DMF (to reduce the concentration of reactants such as zinc nitrate hexahydrate and benzoic acid, avoiding excessively high concentrations that could lead to rapid precipitation, crystal defects, or uneven size, thus promoting slow and uniform nucleation and growth of Zn-TCPP crystals). Place the mixture on a magnetic stirrer and stir continuously in an oil bath at 90 °C for 4 hours. After the reaction is complete, allow the mixture to cool naturally to room temperature, then centrifuge at 8000 rpm for 5 minutes and collect the purple precipitate. The precipitate was washed four times with ethanol until the supernatant became colorless. Finally, the washed solid was transferred to a petri dish and dried overnight in a vacuum oven at 70°C to obtain purple Zn-TCPP powder.

[0033] (2) Accurately weigh 0.02 mmol (approximately 20 mg) of the Zn-TCPP powder prepared in step (1), and place it together with 0.4 mmol (approximately 87.7 mg) of zinc acetate dihydrate, 0.8 mmol (approximately 176.8 mg) of indium chloride, and 1.6 mmol (approximately 120.2 mg) of thioacetamide (TAA) into a 50 mL beaker. Add 30 mL of deionized water to the beaker and stir vigorously with a magnetic stirrer for 30 minutes at room temperature to form a uniform pale yellow suspension. Transfer the entire suspension to a 50 mL capacity polytetrafluoroethylene-lined stainless steel high-pressure reactor and seal it tightly. Place the reactor in an oven, heat it to 190°C, and maintain this temperature for 25 hours for a solvothermal reaction.

[0034] (3) After the reaction was completed, the oven was closed and the reactor was allowed to cool naturally to room temperature. The reactor was opened and all the materials in the reactor were transferred to centrifuge tubes and centrifuged at 8000 rpm for 5 minutes to collect the yellow solid precipitate. The precipitate was washed 4 times (30 mL) each with deionized water and anhydrous ethanol. Finally, the solid was dried in a vacuum drying oven at 70℃ for 18 hours, and after grinding, the yellow ZT / ZIS heterojunction catalyst was obtained and named ZT / ZIS-3.

[0035] The addition of benzoic acid acts as a regulator, functioning as a "growth regulator." By precisely controlling the coordination process, the size, morphology, crystallinity, and properties of MOF materials are ultimately optimized.

[0036] Example 2 The only difference between this embodiment and Example 1 is that the amount of Zn-TCPP added in step (2) is 0.005 mmol (5 mg), and the catalyst prepared is named ZT / ZIS-1.

[0037] Example 3 The only difference between this embodiment and Example 1 is that the amount of Zn-TCPP added in step (2) is 0.01 mmol (10 mg), and the catalyst prepared is named ZT / ZIS-2.

[0038] Example 4 The only difference between this embodiment and Example 1 is that the amount of Zn-TCPP added in step (2) is 0.03 mmol (30 mg), and the catalyst prepared is named ZT / ZIS-4.

[0039] Comparative Example 1 The difference between this example and Example 1 is that step (1) is omitted, and Zn-TCPP is not added in step (2). Instead, 0.4 mmol zinc acetate dihydrate, 0.8 mmol indium chloride and 1.6 mmol thioacetamide are dissolved in 30 mL of water for a solvothermal reaction. The subsequent processing steps are the same as in Example 1, and pure ZnIn2S4 nanosheets (named ZIS) are obtained as a catalyst.

[0040] Comparative Example 2: The steps in this example only include step (1) in Example 1, to obtain pure Zn-TCPP as a photocatalyst.

[0041] To fully characterize the chemical and structural features of the catalysts of this invention, X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) were jointly performed on the catalysts obtained in Examples 1-4 and Comparative Examples 1-2. The results are as follows: Figure 1 and 2 As shown.

[0042] Depend on Figure 1XRD analysis showed that the X-ray diffraction patterns of the ZT / ZIS-x series catalysts (including ZT / ZIS-1, ZT / ZIS-2, ZT / ZIS-3, and ZT / ZIS-4) prepared in this invention all simultaneously exhibited characteristic diffraction peaks of ZnIn2S4 (JCPDS standard card) (e.g., 2θ = 21.2°, 27.7°). Compared with the characteristic diffraction peaks of the Zn-TCPP catalyst in Comparative Example 2 (e.g., 2θ ≈ 18.8°), this indicates that the ZT / ZIS-x series catalysts successfully retained the crystal structure of both components. Compared with the pure ZnIn2S4 prepared in Comparative Example 1 (showing only ZnIn2S4 diffraction peaks) and the pure Zn-TCPP prepared in Comparative Example 2 (showing only Zn-TCPP diffraction peaks), the diffraction peaks of the ZT / ZIS-x catalysts are not a simple superposition of the two phases; the characteristic peak positions of Zn-TCPP have undergone observable shifts compared to its pure phase. This peak shift indicates that during the solvothermal in-situ growth process, ZnIn2S4 and Zn-TCPP are not simply physically mixed, but rather strong lattice interactions or electronic coupling occur at the interface, forming a tight heterojunction interface.

[0043] Depend on Figure 2 FT-IR analysis further corroborated the above-mentioned interactions. Compared with the pure Zn-TCPP prepared in Comparative Example 2, pure Zn-TCPP showed a higher concentration at approximately 1694 cm⁻¹. -1 1602 cm -1 and 1462 cm -1 The characteristic vibrational peak at the ZnIn2S4 surface, belonging to the -COOH group, was observed, while in the ZT / ZIS-x catalyst, all of the aforementioned characteristic peaks showed significant attenuation and shift. This change indicates that during the solvothermal in-situ growth process, the interaction between ZnIn2S4 and Zn-TCPP is not a simple physical adsorption, but rather a chemical bond or strong interaction between ZnIn2S4 and functional groups such as -COOH, forming a tight interfacial chemical coupling.

[0044] SEM images of the catalysts in Example 1 and Comparative Examples 1-2, and TEM images of ZT / ZIS-3, are shown below. Figure 3 and Figure 4 As shown, the pure ZnIn2S4 prepared in Example 1 of this invention exhibits a typical nanosheet structure with relatively obvious and smooth sheets; while Zn-TCPP also has two-dimensional sheet characteristics, with thin and flat sheets and slight local stacking. In the composite sample ZT / ZIS-3, ZnIn2S4 almost completely covers Zn-TCPP, forming a continuous and wrinkle-rich composite layer structure, which is beneficial for increasing active sites.

[0045] The element distribution on ZT / ZIS-3 was further verified by TEM-Mapping, and the results are as follows: Figure 5As shown, C, N, In, S, O, and Zn are uniformly dispersed within the observation area, indicating that Zn-TCPP and ZnIn2S4 phases have achieved uniform nanoscale composite, resulting in strong interfacial interactions and electronic coupling between the two phases.

[0046] The results of UV-Vis DRS analysis of pure ZnIn2S4 (ZIS), pure Zn-TCPP, and the ZT / ZIS-3 composite catalyst of this invention are as follows: Figure 6 This indicates that, compared with pure ZIS and Zn-TCPP, ZT / ZIS-3 exhibits a significant redshift at the absorption edge, suggesting enhanced absorption of visible light.

[0047] The it curves of pure ZIS, pure Zn-TCPP, and ZT / ZIS-3 prepared in Example 1 are shown below. Figure 7 As shown in the figure, the photocurrent density generated by the ZT / ZIS-3 catalyst is significantly higher than that of the two single components (pure ZIS and pure Zn-TCPP). This indicates that the successful construction of the heterojunction greatly promotes the separation of photogenerated electron-hole pairs and effectively suppresses their recombination, thereby significantly improving the photoelectric conversion efficiency.

[0048] The catalysts obtained in Examples 1-4 and Comparative Examples 1-2 were subjected to photocatalytic hydrogen peroxide production via the following steps: In a quartz reaction tube, 20 mg of the pure Z15 and pure Zn to be tested were added respectively. TCPP and ZT / ZIS-x catalysts were mixed with 50 mL of ultrapure water. The suspension was ultrasonically dispersed for 5 minutes, followed by magnetic stirring in the dark for 30 minutes, while high-purity oxygen was continuously bubbled into the solution at a flow rate of 100 mL / min for 30 minutes to achieve adsorption-desorption equilibrium and saturate the solution with dissolved oxygen. A 300 W xenon lamp was used as the light source, with a 420 nm long-pass cutoff filter installed before the light path to ensure that only visible light irradiated the reaction system. The light source was turned on for irradiation, and magnetic stirring was maintained during the reaction. The reaction temperature was kept constant at 20 °C using an external circulating water bath. Every certain period of time (e.g., 15 / 30 minutes), 1 mL of the reaction solution (1-1.2 mL) was drawn with a syringe and immediately filtered through a 0.22 μm aqueous filter to remove the catalyst. The H2O2 concentration in the filtrate was determined using iodometric titration: 1 mL of filtrate was taken, and 1 mL of 0.1 mol / L potassium hydrogen phthalate buffer and 1 mL of 0.4 mol / L potassium iodide solution were added sequentially. After mixing, the solution was allowed to stand in the dark for 60 minutes. The absorbance of the solution at 350 nm was measured using a UV-Vis spectrophotometer, and the actual concentration was calculated based on a pre-established H2O2 concentration-absorbance standard curve.

[0049] The results of the above experiments on hydrogen peroxide production are as follows: Figure 8 As shown, under visible light irradiation, the heterojunction catalysts prepared in Examples 1-4 all exhibited significantly better performance than single ZnIn2S4 or Zn-TCPP catalysts. Among them, ZT / ZIS-3 showed the highest activity, with an H2O2 yield of 658 μmol·g. -1 ·h -1 In comparison, the yields of pure ZnIn2S4 and pure Zn-TCPP were only 152 and 129 μmol·g, respectively. -1 ·h -1 This indicates that the composite of Zn-TCPP and ZnIn2S4 produces a significant synergistic effect.

[0050] The ZT / ZIS-3 catalyst prepared in Example 1 was used in a continuous cycle experiment. Each photocatalytic reaction lasted for 1 hour, and the conditions and procedures were the same as those for the photocatalytic production of hydrogen peroxide described above. After each reaction, the reaction solution was centrifuged to recover the solid catalyst. The recovered catalyst was washed three times each with ultrapure water and ethanol, and then vacuum dried at 60°C for use in the next round. This "reaction-recovery-washing-drying" process was repeated 5 times using the same batch of catalyst. The results are as follows: Figure 9 (As shown in the cycling stability section), after 5 cycles, the H2O2 yield of the catalyst remained at 624 μmol·g. -1 ·h -1 The activity retention rate reached over 94%. Furthermore, the XRD pattern of the catalyst after cycling is shown below. Figure 10 The results are largely consistent with those of the fresh catalyst (before cycling), indicating that the heterojunction catalyst has excellent chemical and structural stability during the photocatalytic reaction.

[0051] To evaluate the practicality of the ZT / ZIS-3 catalyst, the reaction solvent for the hydrogen peroxide production experiment was replaced with actual water samples, including tap water, river water, and lake water (all samples were filtered through a 0.22 μm filter membrane before use). The test conditions were exactly the same as those for the photocatalytic hydrogen peroxide production described above. The results are as follows: Figure 11 As shown, ZT / ZIS-3 exhibits good photocatalytic activity for H2O2 production in tap water, river water, and lake water. This demonstrates that the catalyst has a certain tolerance to common ions and impurities in complex aquatic environments and possesses practical application potential.

[0052] In the standard reaction system, the following scavenging agents were added: 5 mM p-benzoquinone (p-BQ, used to scaveng superoxide radical · O2). - ), 10 vol% tert-butanol (TBA, for capturing hydroxyl radicals ·OH), and 10 mM 2,2,6,6-tetramethylpiperidine nitride (TEMPO, for capturing singlet oxygen).1 O2) and 5 mM potassium bromate (KBrO3, as an electron capture agent under N2 atmosphere).

[0053] Figure 12 To elucidate the formation pathway and key reactive species of H2O2, free radical capture experiments were conducted. The results showed that the addition of p-BQ (which captures H2O2)... - KBrO3 (captures electrons e) - After the addition of TBA and TEMPO, the generation of H2O2 was significantly suppressed. This result indicates that in this photocatalytic system, the generation of H2O2 proceeds via a two-electron oxygen reduction reaction pathway, where photogenerated electrons (e... - ) and superoxide radicals (·O2) generated by its reduction of O2 - () is the key active intermediate. This mechanistically confirms that the Z-type heterojunction effectively separates and retains strong reducing electrons, thereby efficiently driving the process of O2 reduction to H2O2 (the background in the figure indicates the amount of hydrogen peroxide produced by the ZT / ZIS-3 catalyst under conditions without the addition of sacrificial and scavenging agents).

[0054] In summary, the Z-type ZT / ZIS-x heterojunction photocatalyst prepared in this invention ingeniously combines the photoelectric properties of the two components, constructing a highly efficient Z-type charge transfer channel. This enables the efficient and stable synthesis of hydrogen peroxide under visible light-driven conditions without the need for sacrificial agents, and demonstrates promising application prospects in various real-world water bodies. This invention provides new material choices and approaches for developing green and low-cost hydrogen peroxide production technologies.

[0055] Example 5 This embodiment provides a method for preparing a Z-type ZnTCPP / ZIS heterojunction catalyst, including the following steps: (1) Weigh 0.0169 mmol (13.4 mg) of 5,10,15,20-tetra(4-carboxyphenyl)porphyrin (TCPP) and place it in a 50 mL round-bottom flask. Add 5 mL of N,N-dimethylformamide (DMF) to the flask and sonicate it for 4 min to initially disperse it. Then, add 0.4225 mmol (approximately 125.7 mg) of zinc nitrate hexahydrate and 0.10 g of benzoic acid. Add another 20 mL of DMF, place the mixture on a magnetic stirrer, and stir continuously in an oil bath at 90 °C for 4 hours. After the reaction is complete, allow the mixture to cool naturally to room temperature, then centrifuge at 8000 rpm for 5 min and collect the purple precipitate. Wash the precipitate three times with ethanol until the supernatant becomes colorless. Finally, transfer the washed solid to a watch glass and dry it overnight in a vacuum drying oven at 60 °C to obtain purple Zn-TCPP powder.

[0056] (2) Accurately weigh 0.02 mmol (approximately 20 mg) of the Zn-TCPP powder prepared in step (1), and place it together with 0.4 mmol (approximately 87.7 mg) of zinc acetate dihydrate, 0.8 mmol (approximately 176.8 mg) of indium chloride, and 1.6 mmol (approximately 120.2 mg) of thioacetamide (TAA) into a 50 mL beaker. Add 30 mL of deionized water to the beaker and stir vigorously with a magnetic stirrer for 30 minutes at room temperature to form a uniform pale yellow suspension. Transfer the entire suspension to a 50 mL capacity polytetrafluoroethylene-lined stainless steel high-pressure reactor and seal it tightly. Place the reactor in an oven, heat it to 180°C, and maintain this temperature for 26 hours for a solvothermal reaction.

[0057] (3) After the reaction was completed, the oven was closed and the reactor was allowed to cool naturally to room temperature. The reactor was opened and all the materials in the reactor were transferred to centrifuge tubes and centrifuged at 8000 rpm for 5 minutes to collect the yellow solid precipitate. The precipitate was washed three times (30 mL) each with deionized water and anhydrous ethanol. Finally, the solid was placed in a vacuum drying oven at 60℃ and dried for 24 hours. After grinding, the yellow ZT / ZIS heterojunction catalyst was obtained.

[0058] Example 6 This embodiment provides a method for preparing a Z-type ZnTCPP / ZIS heterojunction catalyst, including the following steps: (1) Weigh 0.0508 mmol (approximately 40.2 mg) of 5,10,15,20-tetra(4-carboxyphenyl)porphyrin (TCPP) and place it in a 50 mL round-bottom flask. Add 5 mL of N,N-dimethylformamide (DMF) to the flask and sonicate to initially disperse it for 4 min. Then, add 1.27 mmol (approximately 377.8 mg) of zinc nitrate hexahydrate and 0.14 g of benzoic acid. Add another 22 mL of DMF, place the mixture on a magnetic stirrer, and stir continuously in an oil bath at 90 °C for 4 hours. After the reaction is complete, allow the mixture to cool naturally to room temperature, then centrifuge at 8000 rpm for 5 minutes and collect the purple precipitate. Wash the precipitate repeatedly with ethanol 5 times until the supernatant becomes colorless. Finally, transfer the washed solid to a watch glass and dry it overnight in a vacuum drying oven at 80 °C to obtain purple Zn-TCPP powder.

[0059] (2) Accurately weigh 0.02 mmol (approximately 20 mg) of the Zn-TCPP powder prepared in step (1), and place it together with 0.4 mmol (approximately 87.7 mg) of zinc acetate dihydrate, 0.8 mmol (approximately 176.8 mg) of indium chloride, and 1.6 mmol (approximately 120.2 mg) of thioacetamide (TAA) into a 50 mL beaker. Add 30 mL of deionized water to the beaker and stir vigorously with a magnetic stirrer for 30 minutes at room temperature to form a uniform pale yellow suspension. Transfer the entire suspension to a 50 mL capacity polytetrafluoroethylene-lined stainless steel high-pressure reactor and seal it tightly. Place the reactor in an oven, heat it to 200°C, and maintain this temperature for 24 hours for a solvothermal reaction.

[0060] (3) After the reaction was completed, the oven was closed and the reactor was allowed to cool naturally to room temperature. The reactor was opened and all the materials in the reactor were transferred to centrifuge tubes and centrifuged at 8000 rpm for 5 minutes to collect the yellow solid precipitate. The precipitate was washed 5 times (30 mL) each with deionized water and anhydrous ethanol. Finally, the solid was dried in a vacuum drying oven at 80℃ for 26 hours and then ground to obtain the yellow ZT / ZIS heterojunction catalyst.

[0061] The structures and properties of the ZT / ZIS heterojunction catalysts in Examples 5 and 6 are similar to those of the ZT / ZIS-x series catalysts obtained in Examples 1-4.

[0062] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a Z-type ZnTCPP / ZIS heterojunction catalyst, characterized in that: Includes the following steps: Step S1: Synthesis of zinc porphyrin metal-organic framework Zn-TCPP; Step S2: Dissolve Zn-TCPP, zinc salt, indium salt and sulfur source in water, stir well and then carry out a solvothermal reaction; Step S3: After the reaction is complete, cool to room temperature, centrifuge, wash, and dry to obtain the Z-type ZnTCPP / ZIS heterojunction catalyst.

2. The method for preparing a Z-type ZnTCPP / ZIS heterojunction catalyst according to claim 1, characterized in that: The synthesis process of Zn-TCPP in step S1 is as follows: first, 5, 10, 15, 20 4(4) Carboxyphenyl)porphyrin and zinc nitrate hexahydrate dissolve sequentially in N,N Benzoic acid was added as a regulator to dimethylformamide, and the mixture was stirred at 80-100℃ for 4-5 hours. The precipitate was collected by centrifugation, washed, and dried to obtain Zn. TCPP.

3. The method for preparing a Z-type ZnTCPP / ZIS heterojunction catalyst according to claim 2, characterized in that: N,N per 5ml In dimethylformamide, 5, 10, 15, 20 4(4) The molar amount of carboxyphenyl porphyrin added was 0.0169-0.0508 mmol, the molar amount of zinc nitrate hexahydrate added was 0.4225-1.27 mmol, and the amount of benzoic acid added was 0.10-0.14 g; After adding benzoic acid, then add N,N Dimethylformamide, followed by N,N The amount of dimethylformamide was 4-4.4 times that of before.

4. The method for preparing a Z-type ZnTCPP / ZIS heterojunction catalyst according to claim 2, characterized in that: The washing conditions are: wash with ethanol 3 to 5 times; the drying conditions are: vacuum drying at 60 to 80°C.

5. The method for preparing a Z-type ZnTCPP / ZIS heterojunction catalyst according to claim 1, characterized in that: In step S2, the zinc salt is zinc acetate dihydrate, the indium salt is indium chloride, and the sulfur source is thioacetamide.

6. The method for preparing a Z-type ZnTCPP / ZIS heterojunction catalyst according to claim 1, characterized in that: In step S2, the molar ratio of Zn-TCPP, zinc salt, indium salt and sulfur source is 0.004-0.04:0.4:0.8:1.6; the amount of Zn-TCPP added per 30 mL of water is 5-30 mg.

7. The method for preparing a Z-type ZnTCPP / ZIS heterojunction catalyst according to claim 1, characterized in that: In step S2, the reaction temperature of the solvothermal reaction is 180~200℃, and the reaction time is 24~26h.

8. The method for preparing a Z-type ZnTCPP / ZIS heterojunction catalyst according to claim 1, characterized in that: In step S3, the washing conditions are: first wash with deionized water 3 to 5 times, then wash with ethanol 3 to 5 times; the drying conditions are: vacuum drying at 60 to 80°C overnight.

9. The Z-type ZnTCPP / ZIS heterojunction catalyst prepared by the preparation method according to any one of claims 1-8, characterized in that: The catalyst is a hierarchical heterostructure assembled from Zn-TCPP and ZnIn2S4 nanosheets, and the mass percentage of Zn-TCPP in the catalyst is 3-16 wt%.

10. The application of the Z-type ZnTCPP / ZIS heterojunction catalyst according to claim 9 in photocatalytic hydrogen peroxide production, characterized in that: The catalyst was dispersed in an oxygen-saturated aqueous solution and then catalyzed to react water and oxygen to produce hydrogen peroxide under visible light irradiation.

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