Carbon-containing phosphating metal-sulfur indium zinc composite material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of catalysis, and particularly relates to a carbon-containing phosphating metal-sulfur indium zinc composite material and a preparation method and application thereof. The carbon-containing phosphating metal-sulfur indium zinc composite material comprises sulfur indium zinc nano flower cluster microspheres and carbon-containing phosphating metal nanoparticles, the sulfur-indium-zinc nano flower cluster microspheres are aggregates of sulfur-indium-zinc nanosheets, and the chemical component of the sulfur-indium-zinc nanosheets is ZnIn2S4. The carbon-containing phosphatized metal nanoparticles are loaded on the surfaces of sulfur indium zinc nanosheets in the sulfur indium zinc nano flower cluster microspheres. The carbon-containing phosphating metal-sulfur indium zinc composite material can inhibit electron hole pair compounding, increase photocatalytic active sites and improve the photocatalytic water splitting hydrogen production activity.

Description

Technical Field

[0001] The invention belongs to the technical field of catalysis, and in particular relates to a carbon-containing metal phosphide-indium zinc sulfide composite material and a preparation method and application thereof. Background Art

[0002] The over-exploitation of fossil fuels such as oil, coal and natural gas and the environmental pollution caused by their products have always been urgent problems to be solved. In order to solve the above problems, researchers have turned their attention to seeking alternative clean renewable energy sources, such as hydrogen. At present, the use of visible light photocatalytic decomposition of water to produce hydrogen is the most widely studied technology for preparing hydrogen. On the one hand, available natural resources such as sunlight and water are inexhaustible. On the other hand, hydrogen, as an ideal secondary energy source, has the advantages of high calorific value and pollution-free products and is widely used in industrial production. However, in the process of using semiconductors as photocatalysts to decompose water to produce hydrogen under visible light, the electron-hole pairs generated by photoexcitation recombine seriously, and the corresponding photocatalytic performance is low. Therefore, it is urgent to find a convenient and effective strategy to solve the above problems of photocatalysts and improve the activity of photocatalytic decomposition of water to produce hydrogen.

[0003] ZnIn2S4 is a common ternary sulfide, which is widely used in photocatalysis due to its suitable band gap and high stability. Studies have found that this layered compound has anisotropic conductivity. It is manifested in that the photogenerated electrons tend to be transmitted along the direction perpendicular to the (001) direction and finally reach a specific active surface for reduction reaction. However, due to the small area of ​​the exposed active surface during the formation of ZnIn2S4 crystals, and most of the photogenerated electron-hole pairs that reach the active surface recombine, resulting in fewer active sites, which reduces its performance in photocatalytic water decomposition to produce hydrogen. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a carbon-containing metal phosphide-indium zinc sulfur composite material and a preparation method and application thereof, wherein the carbon-containing metal phosphide-indium zinc sulfur composite material can inhibit the recombination of electron-hole pairs, increase photocatalytic active sites, and improve the activity of photocatalytic water decomposition to produce hydrogen.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides a carbon-containing metal phosphide-indium zinc sulfide composite material, comprising:

[0007] Indium zinc sulfide nanoflower cluster microspheres and carbon-containing metal phosphide nanoparticles;

[0008] The sulfur indium zinc nano flower cluster microspheres are aggregates of sulfur indium zinc nanosheets, and the chemical composition of the sulfur indium zinc nanosheets is ZnIn2S4;

[0009] The carbon-containing metal phosphide nanoparticles are loaded on the surface of zinc indium sulfide nanosheets in the zinc indium sulfide nanoflower cluster microspheres.

[0010] Preferably, the metal element in the carbon-containing metal phosphide nanoparticles is one or more of Co, Cu, and Ni.

[0011] Preferably, the particle size of the zinc indium sulfide nanoflower cluster microspheres is 1-5 μm, and the specific surface area is 40-50 m 2 / g; the sheet diameter of the zinc indium sulfide nanosheets is 1-2 μm; the particle size of the carbon-containing metal phosphide nanoparticles is 500-1000 nm.

[0012] Preferably, the mass percentage content of the zinc indium sulfide nanoflower cluster microspheres in the carbon-containing metal phosphide-zinc indium sulfide composite material is 30-70%, and the mass percentage content of the carbon-containing metal phosphide nanoparticles is 30-70%.

[0013] The present invention also provides a preparation method of the carbon-containing metal phosphide-zinc indium sulfide composite material described in the above technical solution, including the following steps:

[0014] Annealing the metal-organic framework material and sodium hypophosphite in a protective gas to obtain carbon-containing metal phosphide nanoparticles;

[0015] Mixing and loading the carbon-containing metal phosphide nanoparticles and zinc indium sulfide nanoflower cluster microspheres in a polar solvent to obtain the carbon-containing metal phosphide-zinc indium sulfide composite material.

[0016] Preferably, the annealing temperature is 270-330 °C, and the heat preservation time is 1-3 h.

[0017] Preferably, the loading method is ultrasonic treatment; the power of the ultrasonic treatment is 80-120 W, the temperature is 20-30 °C, and the time is 10-20 min.

[0018] Preferably, the preparation method of the zinc indium sulfide nanoflower cluster microspheres includes the following steps: performing a solvothermal reaction on the precursor solution to obtain zinc indium sulfide nanoflower cluster microspheres, and the precursor solution includes a zinc salt, an indium salt, a sulfur-containing substance, and an aqueous alcohol solution.

[0019] The present invention also provides an application of the carbon-containing metal phosphide-zinc indium sulfide composite material described in the above technical solution or the carbon-containing metal phosphide-zinc indium sulfide composite material prepared by the preparation method described in the above technical solution as a photocatalyst.

[0020] The present invention also provides a method for photocatalytic water splitting to produce hydrogen, including the following steps:

[0021] Photocatalytically decomposing and producing hydrogen from an aqueous solution containing a photocatalyst under light irradiation to obtain hydrogen;

[0022] The photocatalyst is the carbon-containing metal phosphide-zinc indium sulfide composite material described in the above technical solution or the carbon-containing metal phosphide-zinc indium sulfide composite material prepared by the preparation method described in the above technical solution.

[0023] The present invention provides a carbon-containing metal phosphide-zinc indium sulfide composite material, including: zinc indium sulfide nanocluster microspheres and carbon-containing metal phosphide nanoparticles; the zinc indium sulfide nanocluster microspheres are aggregates of zinc indium sulfide nanosheets, and the chemical composition of the zinc indium sulfide nanosheets is ZnIn2S4; the carbon-containing metal phosphide nanoparticles are loaded on the surface of the zinc indium sulfide nanosheets in the zinc indium sulfide nanocluster microspheres. In the present invention, the carbon-containing metal phosphide nanoparticles are amorphous materials. As a cocatalyst, they can improve the transport characteristics of excited carriers, provide active sites for photocatalytic reactions, can not only act as electron receivers, but also provide proton reduction sites, can improve the stability of the zinc indium sulfide nanocluster microspheres, and inhibit the self-decomposition of sulfides by extracting photo-generated holes for oxygen evolution reaction, thereby enhancing the photocatalytic activity of the zinc indium sulfide nanocluster microspheres. The carbon-containing metal phosphide nanoparticles, as effective cocatalysts on the surface of the zinc indium sulfide nanocluster microspheres, greatly inhibit the recombination of electrons and holes and greatly increase the surface charge density. In addition, the carbon skeleton with a graphite sp2 hybrid structure can achieve strong electron interaction in the interfacial layer. This enhanced activity is attributed to the fact that the metal-based phosphide derived from the metal-organic framework material can separate the photo-generated charge carriers formed in the zinc indium sulfide nanocluster microspheres, effectively improving the photocatalytic water splitting hydrogen production activity of the carbon-containing metal phosphide-zinc indium sulfide composite material. Description of the Drawings

[0024] Figure 1 It is a schematic flow chart of the method for preparing the carbon-containing metal phosphide-zinc indium sulfide composite material in the embodiment of the present invention;

[0025] Figure 2 It is the XRD patterns of the zinc indium sulfide nanocluster microspheres (ZIS) of Comparative Example 1, CoPC of Comparative Example 2, Z 70 -CoPC 30 of Example 1, Z 50 -CoPC 50 of Example 2, and Z 30 -CoPC 70 of Example 3;

[0026] Figure 3 It is the XRD patterns of the zinc indium sulfide nanocluster microspheres (ZIS) of Comparative Example 1, CoPC of Comparative Example 2, Z 70 -CoPC 30 of Example 1, Z 50 -CoPC 50 of Example 2, and Z30 -CoPC 70 Photocurrent density test chart of

[0027] Figure 4 For zinc indium sulfide nanosheet cluster microspheres (ZIS) of Comparative Example 1, CoPC of Comparative Example 2, and Z of Example 1 70 -CoPC 30 and Z of Example 2 50 -CoPC 50 and Z of Example 3 30 -CoPC 70 Photocatalytic hydrogen production comparison chart of

[0028] Figure 5 For zinc indium sulfide nanosheet cluster microspheres (a) of Comparative Example 1, ZIF-67 and phosphated CoPC (b) in Comparative Example 2, and Z of Example 2 50 -CoPC 50 (c) Scanning electron microscope image and Z of Example 2 50 -CoPC 50 (d) EDS energy spectrum diagram of Detailed implementation manners

[0029] The present invention provides a carbon-containing phosphated metal-zinc indium sulfide composite material, comprising:

[0030] Zinc indium sulfide nanosheet cluster microspheres and carbon-containing phosphated metal nanoparticles;

[0031] The zinc indium sulfide nanosheet cluster microspheres are aggregates of zinc indium sulfide nanosheets, and the chemical composition of the zinc indium sulfide nanosheets is ZnIn2S4;

[0032] The carbon-containing phosphated metal nanoparticles are loaded on the surface of the zinc indium sulfide nanosheets in the zinc indium sulfide nanosheet cluster microspheres.

[0033] Unless otherwise specified, the present invention has no special requirements for the sources of the raw materials used, and commercially available products well-known to those skilled in the art can be used.

[0034] As an implementation manner, the ZnIn2S4 has a hexagonal crystal system structure, which is composed of Zn atoms or In atoms distributed in the octahedral or tetrahedral voids between S atomic layers, and the structural units are periodically stacked along the c-axis.

[0035] As an implementation manner, the carbon-containing phosphated metal nanoparticles are amorphous materials; the metal elements in the carbon-containing phosphated metal nanoparticles are one or more of Co, Cu, and Ni, and are Co in specific embodiments.

[0036] As an embodiment, the particle size of the zinc indium sulfide nanosheet cluster microspheres is 1-5 μm, specifically 3-5 μm in specific embodiments, and the specific surface area is 40-50 m 2 / g, specifically 45.93 m 2 / g in specific embodiments; the sheet diameter of the zinc indium sulfide nanosheets is 1-2 μm; the particle size of the carbon-containing metal phosphide nanoparticles is 500-1000 nm. In the present invention, the zinc indium sulfide nanosheet cluster microspheres are flower spheres assembled from zinc indium sulfide nanosheets. The sheet-like structure of the zinc indium sulfide nanosheet cluster microspheres has a large area, and the carbon-containing metal phosphide nanoparticles are easily attached to its surface

[0037] As an embodiment, the mass percentage content of the zinc indium sulfide nanosheet cluster microspheres in the carbon-containing metal phosphide-zinc indium sulfide composite material is 30-70%, specifically 30%, 50% or 70% in specific embodiments, and the mass percentage content of the carbon-containing metal phosphide nanoparticles is 30-70%, specifically 30%, 50% or 70% in specific embodiments.

[0038] In the present invention, the carbon-containing metal phosphide nanoparticles containing metal phosphides are used as co-catalysts and loaded with zinc indium sulfide nanosheet cluster microspheres. The carbon-containing metal phosphide nanoparticles can improve the transport characteristics of excited carriers, thereby promoting the photocatalytic activity of the zinc indium sulfide nanosheet cluster microspheres. They can also provide active sites for photocatalytic reactions. They can not only act as electron receivers but also provide proton reduction sites, which can improve the stability of the zinc indium sulfide nanosheet cluster microspheres. By extracting photogenerated holes for oxygen evolution reaction to inhibit the self-decomposition of sulfides, the photocatalytic activity of the zinc indium sulfide nanosheet cluster microspheres is enhanced. First-principles calculations and experimental data show that the carbon-containing metal phosphide nanoparticles are effective co-catalysts on the surface of the zinc indium sulfide nanosheet cluster microspheres, and the recombination of electrons and holes is greatly inhibited, and the surface charge density is greatly increased. In addition, the carbon skeleton with a graphite sp2 hybrid structure can achieve strong electron interaction in the interfacial layer. This enhanced activity is attributed to the metal-based phosphides derived from metal-organic framework materials that can separate the photogenerated charge carriers formed in the zinc indium sulfide nanosheet cluster microspheres, and it shows that the presence of the carbon-containing metal phosphide as a co-catalyst in the composite material improves the effectiveness of the carbon-containing metal phosphide-zinc indium sulfide composite (Z-carbon-containing metal phosphide) photocatalyst. Therefore, the Z-carbon-containing metal phosphide photocatalyst with the best performance exhibits an excellent hydrogen evolution rate of 2.1 mmol·g -1 ·h -1 .

[0039] The present invention also provides a preparation method of the carbon-containing metal phosphide-zinc indium sulfide composite material described in the above technical solution, including the following steps:

[0040] Anneal the metal-organic framework material and sodium hypophosphite in a protective gas to obtain carbon-containing metal phosphide nanoparticles;

[0041] Mix and load the carbon-containing metal phosphide nanoparticles and zinc indium sulfide nanoflower cluster microspheres in a polar solvent to obtain the carbon-containing metal phosphide-zinc indium sulfide composite material.

[0042] In the present invention, a metal-organic framework material and sodium hypophosphite are annealed in a protective gas to obtain carbon-containing metal phosphide nanoparticles.

[0043] As an implementation manner, the metal base in the metal-organic framework material is one or more of Co, Cu, and Ni, and in specific embodiments, it is Co, or Cu, or Co and Ni.

[0044] As an implementation manner, the preparation method of the metal-organic framework material includes the following steps: mix a metal salt, an organic ligand, and a polar solvent, and perform a coordination reaction on the obtained coordination reaction precursor solution to obtain the metal-organic framework material.

[0045] As an implementation manner, the metal salt includes one or more of cobalt salts, nickel salts, and copper salts, and in specific embodiments, it is a cobalt salt; the cobalt salt is cobalt nitrate and / or cobalt chloride, and in specific embodiments, it is cobalt nitrate; the nickel salt is nickel nitrate and / or nickel chloride, and in specific embodiments, it is nickel nitrate; the copper salt is copper nitrate and / or copper chloride, and in specific embodiments, it is copper nitrate; the organic ligand is dimethylimidazole (C4H6N2); the polar solvent is one or more of methanol, ethanol, and water, and in specific embodiments, it is methanol.

[0046] As an implementation manner, mixing the metal salt, the organic ligand, and the polar solvent is as follows: dissolve the metal salt in a part of the polar organic solvent to obtain a metal salt solution; dissolve the organic ligand in the remaining polar organic solvent to obtain an organic ligand solution; mix the metal salt solution and the organic ligand solution to obtain a coordination reaction precursor solution; the volume ratio of the metal salt solution to the organic ligand solution is 1:0.6 - 1.5, and in specific embodiments, it is 1:1; the concentration of the metal salt in the metal salt solution is 0.05 - 0.1 mol / L, and in specific embodiments, it is 0.05 - 0.09 mol / L, and the concentration of the organic ligand in the organic ligand solution is 0.09 - 0.3 mol / L, and in specific embodiments, it is 0.125 - 0.24 mol / L.

[0047] As an implementation manner, the coordination reaction is carried out by stirring and then standing in sequence; the stirring time is 10 - 60 min, and in specific embodiments, it is 20 - 40 min; the standing time is 10 - 24 h, and in specific embodiments, it is 16 - 24 h. The present invention has no special limitation on the stirring rate, and a well-known stirring rate in the art can be adopted, and it is sufficient to stir as fast as possible.

[0048] In the present invention, the metal ions and the organic ligands are fully combined by static standing.

[0049] As an embodiment, after the coordination reaction, it further includes: after solid-liquid separation of the product obtained from the coordination reaction, the precipitate obtained is washed; the solid-liquid separation is centrifugation or suction filtration, specifically suction filtration in the specific embodiment; the rotation speed of the centrifugation is 8000-10000 rpm, specifically 8000-9000 rpm in the specific embodiment; the time of the centrifugation is 10-20 min, specifically 10-15 min in the specific embodiment; the reagent used for washing is one or several of methanol, ethanol and water, specifically methanol in the specific embodiment; the washing is carried out until there is no suspended matter, specifically until there is no purple suspended matter in the specific embodiment.

[0050] As an embodiment, the mass ratio of the metal-organic framework material to sodium hypophosphite is 1:3-10, specifically 1:5 in the specific embodiment; the protective gas is nitrogen or argon, specifically argon in the specific embodiment; the annealing temperature is 270-330 °C, specifically 280-310 °C in the specific embodiment, and the heat preservation time is 1-3 h, specifically 2 h in the specific embodiment; the heating rate for heating to the annealing temperature is 1-10 °C / min, specifically 3-5 °C / min in the specific embodiment; the equipment used for annealing is a tube furnace and a porcelain boat; during the annealing process, the metal-organic framework material and sodium hypophosphite are placed on both sides of the porcelain boat, and sodium hypophosphite is located on the upstream side of the tube furnace.

[0051] During the annealing process, NaH2PO2 is heated to become PH3 gas. The PH3 gas is carried by argon to phosphide the metal ions in the metal-organic framework material to generate phosphided metal. The organic ligands in the metal-organic framework material are partially carbonized to form carbon-containing phosphided metal nanoparticles containing amorphous carbon. The carbon-containing phosphided metal nanoparticles lose the original dodecahedron structure of the metal-organic framework material (MOFs), undergo structure collapse, disperse into fragments, and become fragmented small particles.

[0052] As an embodiment, after the annealing, it further includes: washing and drying the product obtained from the annealing in sequence; the reagents used for washing are ethanol and deionized water; the number of washing times is 2-5 times for each reagent used for washing, specifically 3-4 times in the specific embodiment; the drying temperature is 50-80 °C, specifically 60-70 °C in the specific embodiment; the drying time is 6-12 h, specifically 8-12 h in the specific embodiment.

[0053] As an embodiment, the preparation method of the zinc indium sulfide nanosheet cluster microspheres includes the following steps: subjecting a precursor solution to a solvothermal reaction to obtain zinc indium sulfide nanosheet cluster microspheres, and the precursor solution includes a zinc salt, an indium salt, a sulfur-containing substance and an alcohol aqueous solution.

[0054] As an implementation manner, the zinc salt is one or more of zinc chloride, zinc nitrate and zinc sulfate, specifically zinc chloride in a specific embodiment; the indium salt is one or more of indium chloride, indium nitrate and indium sulfate, specifically indium chloride in a specific embodiment; the sulfur-containing substance is thioacetamide (TAA, C2H5NS) and / or thiourea (CH4N2S), specifically thioacetamide or thiourea in a specific embodiment; the aqueous alcohol solution includes ethanol and water; the volume ratio of ethanol to water is 1:0.8 - 2, specifically 1:1 in a specific embodiment.

[0055] As an implementation manner, the preparation method of the precursor solution is: mixing the zinc salt, indium salt, sulfur-containing substance and aqueous alcohol solution; the mixing is to perform a first stirring on the zinc salt, indium salt and aqueous alcohol solution, and then adding the sulfur-containing substance for a second stirring; the rotation speeds of the first stirring and the second stirring are 200 - 500 rpm, specifically 300 - 400 rpm in a specific embodiment; the time of the first stirring and the second stirring is independently 10 - 40 min, specifically 10 - 30 min in a specific embodiment; the concentration of the zinc salt in the precursor solution is 0.01 - 0.03 mol / L, specifically 0.017 mol / L in a specific embodiment, the concentration of the indium salt is 1.2 - 3 times that of the zinc salt, specifically 1.5 - 2.5 times in a specific embodiment, and the concentration of the sulfur-containing substance is 3.5 - 8 times that of the zinc salt, specifically 4 - 6 times in a specific embodiment.

[0056] As an implementation manner, the temperature of the solvothermal reaction is 130 - 180 °C, specifically 160 - 180 °C in a specific embodiment, the heat preservation time is 6 - 12 h, specifically 8 - 10 h in a specific embodiment; the heating rate to the temperature of the solvothermal reaction is 1 - 5 °C / min, specifically 1 - 3 °C / min in a specific embodiment; the equipment used for the solvothermal reaction is a reaction kettle; the inner liner of the reaction kettle is a polytetrafluoroethylene inner liner, and the outer shell is a stainless steel outer shell; the volume of the precursor solution for the solvothermal reaction accounts for 40 - 80% of the volume of the reaction kettle, specifically 50 - 60% in a specific embodiment.

[0057] As an implementation manner, after the solvothermal reaction, it further includes: after cooling the product obtained from the solvothermal reaction to room temperature, performing solid-liquid separation, and washing and drying the obtained precipitate in sequence to obtain zinc indium sulfide nanosheet cluster microspheres; the cooling is natural cooling; the washing is to perform centrifugal washing with distilled water and ethanol in sequence for 2 - 5 times each, specifically 3 times in a specific embodiment; the rotation speed of the centrifugal washing is 8000 - 10000 rpm, specifically 8000 - 9000 rpm in a specific embodiment; the time of the centrifugal washing is 10 - 20 min, specifically 10 - 15 min in a specific embodiment; the drying temperature is 50 - 80 °C, specifically 60 - 70 °C in a specific embodiment; the drying time is 6 - 12 h, specifically 8 - 12 h in a specific embodiment; the drying is carried out in air.

[0058] After obtaining the carbon-containing metal phosphide nanoparticles, the present invention mixes and loads the carbon-containing metal phosphide nanoparticles and zinc indium sulfide nanoflower cluster microspheres in a polar solvent to obtain the carbon-containing metal phosphide-zinc indium sulfide composite material.

[0059] As an embodiment, the mass ratio of the carbon-containing metal phosphide nanoparticles to the zinc indium sulfide nanoflower cluster microspheres is 30-70:70-30, specifically 30:70, 50:50 or 70:30 in specific examples; the polar solvent is methanol; the mass of the zinc indium sulfide nanoflower cluster microspheres to the volume of the polar solvent is (30-70) mg:(30-80) mL, specifically 70 mg:80 mL, 50 mg:30 mL or 30 mg:80 mL in specific examples; the mixing is carried out under stirring; the stirring rate is 200-500 rpm, specifically 300-400 rpm in specific examples; the loading method is ultrasonic treatment; the power of the ultrasonic treatment is 80-120 W, specifically 100-110 W in specific examples, the temperature is 20-30 °C, specifically 20-25 °C in specific examples, and the time is 10-20 min, specifically 10 min in specific examples.

[0060] During the ultrasonic treatment, the carbon-containing metal phosphide nanoparticles and the zinc indium sulfide nanoflower cluster microspheres are fully combined by electrostatic adsorption for loading to obtain the carbon-containing metal phosphide-zinc indium sulfide composite material.

[0061] As an embodiment, after the ultrasonic treatment, it further includes: filtering by suction and then drying; the drying temperature is 60-80 °C, specifically 60-70 °C in specific examples; the drying time is 1-2 h, specifically 2 h in specific examples.

[0062] Figure 1 It is a schematic flow chart of the method for preparing the carbon-containing metal phosphide-zinc indium sulfide composite material in the embodiments of the present invention. As Figure 1 shown, the present invention mixes zinc salt (ZnCl2), indium salt (InCl3·4H2O), sulfur-containing substance (TAA) and aqueous alcohol solution (C2H5OH + H2O) to carry out a solvothermal reaction to generate zinc indium sulfide nanospheres (ZnIn2S4, ZIS), and mixes an organic ligand (C4H6N2) and a metal salt (Co 2+ ) to carry out a coordination reaction to generate a metal-organic framework material (ZIF-67), then phosphides the metal with sodium hypophosphite (NaH2PO2) during annealing to generate carbon-containing metal phosphide particles (CoPC), and then loads ZIS and CoPC to obtain the carbon-containing metal phosphide-zinc indium sulfide composite material (Z x -CoPC y ).

[0063] The present invention also provides an application of the carbon-containing metal phosphide-zinc indium sulfide composite material described in the above technical solution or the carbon-containing metal phosphide-zinc indium sulfide composite material prepared by the preparation method described in the above technical solution as a photocatalyst.

[0064] The present invention also provides a method for photocatalytic water splitting to produce hydrogen, comprising the following steps:

[0065] Performing photocatalytic hydrogen production by photolysis on an aqueous solution containing a photocatalyst under light irradiation to obtain hydrogen;

[0066] The photocatalyst is the carbon-containing metal phosphide-zinc indium sulfide composite material described in the above technical solution or the carbon-containing metal phosphide-zinc indium sulfide composite material prepared by the preparation method described in the above technical solution.

[0067] As an embodiment, the mass concentration of the photocatalyst in the aqueous solution containing the photocatalyst is 0.3-0.7 g / L, and in a specific embodiment it is 0.67 g / L; the aqueous solution containing the photocatalyst further includes a sacrificial agent; the sacrificial agent is triethanolamine; the concentration of the sacrificial agent in the aqueous solution containing the photocatalyst is 5-20% (v / v), and in a specific embodiment it is 10% (v / v); the light source used for the light irradiation is sunlight or visible light, and in a specific embodiment it is visible light; the wavelength of the light source used for the light irradiation is 420-800 nm; the power of the light irradiation is 9-10 W, and in a specific embodiment it is 10 W; the average light power density of the light irradiation is 9-10 mW / cm 2 and in a specific embodiment it is 10 mW / cm 2 ; the temperature for the photocatalytic hydrogen production by photolysis is 20-25 °C, and in a specific embodiment it is 20 °C, and the time is 9-12 h, and in a specific embodiment it is 10 h; the simulated visible light is provided by a photochemical workstation, and in a specific embodiment it is the MCP-WS1000 type photochemical workstation produced by Beijing Perfectlight Technology Co., Ltd.

[0068] As an embodiment, the hydrogen evolution rate of the photocatalytic hydrogen production by photolysis is 1.7-2.1 mmol·g -1 ·h -1 and in a specific embodiment it is 2.1 mmol·g -1 ·h -1 .

[0069] The extensive and close contact interface between the zinc indium sulfide nanospheres and the CoPC nanofragments in the carbon-containing metal phosphide-zinc indium sulfide composite material, together with the strong coupling effect between them, promotes light capture, charge separation, rapid charge carrier transport, and utilization of active adsorption sites, increases the active sites of the carbon-containing metal phosphide-zinc indium sulfide composite material, and effectively improves its activity for photocatalytic water splitting to produce hydrogen as a photocatalyst.

[0070] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention, but they should not be construed as limiting the protection scope of the present invention.

[0071] Example 1

[0072] Synthesis of cobalt-based metal-organic framework material (Co-MOFs) ZIF-67: 3.6 mmol (1.048 g) of Co(NO3)2·6H2O was dissolved in methanol (40 mL) to obtain a homogeneous solution A; 40 mL of methanol and 9.6 mmol of dimethylimidazole (C4H6N2) were mixed to obtain a homogeneous solution B. Then the two solutions were mixed and stirred for 10 min for a coordination reaction, followed by standing and precipitating for 24 h. After centrifuging at 8000 rpm for 10 min, the obtained precipitate was washed with methanol until there was no purple suspension, and a cobalt-based metal-organic framework material was obtained, named ZIF-67;

[0073] Synthesis of CoPC: The synthesized Co-MOFs (ZIF-67, 100 mg) and NaH2PO2 (500 mg) were placed on both sides of a porcelain boat, and NaH2PO2 was located on the upstream side of the tube furnace. Subsequently, it was heated at 300 °C in argon for 120 min. The PH3 gas generated by the heating of NaH2PO2 carried out phosphidation of Co to generate cobalt phosphide by argon. The heating rate in the argon atmosphere was 5 °C / min. The obtained product was washed 3 times each with ethanol and deionized water, and then dried at 60 °C for 12 h to obtain carbon-containing cobalt phosphide nanoparticles, named CoPC.

[0074] Synthesis of ZnIn2S4 (ZIS) nanoflower cluster microspheres: ZnCl2 (0.5 mmol, 0.06814 g) and InCl3·4H2O (1.0 mmol, 0.293 g) were added to a 30 mL mixed solution of ethanol and water with an equal volume ratio, and stirred at 350 rpm for 10 min. Then thioacetamide (TAA, 2 mmol, 0.1503 g) was added to the obtained mixed solution, and stirred at 300 rpm for 30 min. The finally obtained precursor solution was transferred to a 50 mL polytetrafluoroethylene-lined stainless steel autoclave, heated at 1 °C / min, and subjected to a hydrothermal reaction at 453 K (180 °C) for 10 h. After natural cooling to room temperature, suction filtration was carried out to obtain a yellow ZnIn2S4 precipitate. The obtained product was centrifugally washed 3 times each with distilled water and ethanol, with a rotation speed of 8000 rpm and a time of 10 min each time, and then dried in air at 333 K (60 °C) for 12 h to obtain zinc indium sulfide nanoflower cluster microspheres;

[0075] Synthesis of ZIS / CoPC (Z-CoPC): 70 mg of zinc indium sulfide nanoflower cluster microspheres and 30 mg of CoPC were stirred evenly in 80 mL of methanol at 400 rpm, and then ultrasonically mixed at 20 °C and 100 W for 10 min to form a gray suspension. The solid obtained by suction filtration was placed in a petri dish and dried at 60 °C for 2 h to obtain the CoPC-zinc indium sulfide composite material, denoted as Z 70 -CoPC 30 .

[0076] Example 2

[0077] Synthesis of cobalt-based metal-organic framework material (Co-MOFs) ZIF-67: 10 mmol (3.2 g) of Co(NO3)2·6H2O was dissolved in methanol (200 mL) to obtain a homogeneous solution A; 200 mL of methanol and 25 mmol of dimethylimidazole (C4H6N2) were mixed to obtain a homogeneous solution B; then the two solutions were mixed and stirred for 10 min for a coordination reaction, and then allowed to stand and precipitate for 24 h. After centrifugation at 8000 rpm for 10 min, the obtained precipitate was washed with methanol until there was no purple suspension to obtain the cobalt-based metal-organic framework material, named ZIF-67;

[0078] Synthesis of CoPC: The synthesized Co-MOFs (ZIF-67, 100 mg) and NaH2PO2 (500 mg) were placed on both sides of a porcelain boat, with NaH2PO2 on the upstream side of the tubular furnace. Subsequently, it was heated in argon at 300 °C for 120 min. The PH3 gas generated by the heating of NaH2PO2 carried out phosphidation of Co by argon to generate cobalt phosphide. The heating rate in the argon atmosphere was 5 °C / min. The obtained product was washed 3 times each with ethanol and deionized water, and then dried at 60 °C for 12 h to obtain carbon-containing cobalt phosphide nanoparticles, named CoPC;

[0079] Synthesis of ZnIn2S4 (ZIS) nanoflower cluster microspheres: ZnCl2 (0.5 mmol, 0.06814 g) and InCl3·4H2O (1.0 mmol, 0.293 g) were added to a 30 mL mixed solution of ethanol and water with an equal volume ratio, and stirred at 300 rpm for 10 min. Then, 2 mmol (0.1523 g) of thiourea was added to the obtained mixed solution and stirred at 400 rpm for 30 min. The finally obtained precursor solution was transferred to a 50 mL Teflon-lined stainless steel autoclave, heated at 1 °C / min, and subjected to a hydrothermal reaction at 453 K (180 °C) for 10 h. After natural cooling to room temperature, suction filtration was carried out to obtain a yellow ZnIn2S4 precipitate. The obtained product was centrifugally washed 3 times with distilled water and ethanol respectively, with a centrifugal washing speed of 8000 rpm and a time of 10 min. Then, it was dried in air at 333 K (60 °C) for 12 h to obtain zinc indium sulfide nanoflower cluster microspheres (ZIS);

[0080] Synthesis of ZIS / CoPC (Z-CoPC): 50 mg of zinc indium sulfide nanoflower cluster microspheres and 50 mg of CoPC were stirred evenly in 30 mL of methanol at 400 rpm, and then ultrasonicated at 20 °C and 100 W for 10 min to form a gray suspension. The solid obtained by suction filtration was placed in a petri dish and dried at 60 °C for 2 h to obtain a CoPC-zinc indium sulfide composite material, denoted as Z 50 -CoPC 50 。

[0081] Example 3

[0082] The difference from Example 1 is that 30 mg of zinc indium sulfide nanoflower cluster microspheres and 70 mg of CoPC were ultrasonically treated, and the rest was the same as in Example 1, to obtain Z 30 -CoPC 70 。

[0083] Comparative Example 1

[0084] The zinc indium sulfide nanoflower cluster microspheres (ZIS) prepared in Example 1 were used as the comparative example.

[0085] Comparative Example 2

[0086] CoPC prepared in Example 1 was used as the comparative example.

[0087] Application Example 1

[0088] Using the MCP-WS1000 type photochemical workstation produced by Beijing Perfectlight Technology Co., Ltd. for the Z prepared in Example 1 70 -CoPC 30The photocatalytic hydrogen production experiment under simulated sunlight irradiation was carried out. The visible light source of this workstation is 420 - 800 nm, with a power of 10 W and an average light power density of 10 mW / cm 2 , and the experimental system was composed of 20 mg of photocatalyst (Z 70 -CoPC 30 ) dispersed in 10% (v / v) triethanolamine aqueous solution. Among them, the mass concentration of Z 70 -CoPC 30 was 0.67 g / L. To maintain a constant reaction temperature, a water cooling system was used throughout the experiment to control the reaction temperature at 20 °C. Photocatalytic hydrogen production was carried out for 10 h. During the hydrogen evolution reaction process, a GC979011 type gas chromatograph of Fuli Instruments was used to quantitatively detect the generated hydrogen, and the sampling interval was 2 h.

[0089] Application Example 2

[0090] The difference from Application Example 1 was that the Z 70 -CoPC 30 prepared in Example 1 was replaced with the Z 50 -CoPC 50 prepared in Example 2, and the rest was the same as Application Example 1.

[0091] Application Example 3

[0092] The difference from Application Example 1 was that the Z 70 -CoPC 30 prepared in Example 1 was replaced with the Z 30 -CoPC 70 prepared in Example 3, and the rest was the same as Application Example 1.

[0093] Comparative Application Example 1

[0094] The difference from Application Example 1 was that the Z 70 -CoPC 30 prepared in Example 1 was replaced with the zinc indium sulfide nanosheet cluster microspheres of Comparative Example 1, and the rest was the same as Application Example 1.

[0095] Comparative Application Example 2

[0096] The difference from Application Example 1 was that the Z 70 -CoPC 30 prepared in Example 1 was replaced with CoPC of Comparative Example 2, and the rest was the same as Application Example 1.

[0097] Performance Test

[0098] (1) The zinc indium sulfide nanosheet cluster microspheres (ZIS) of Comparative Example 1, CoPC of Comparative Example 2, and Z 70-CoPC 30 and Z of Example 2 50 -CoPC 50 and Z of Example 3 30 -CoPC 70 The crystal structures are as shown in Figure 2 .

[0099] It can be seen from Figure 2 that obvious diffraction peaks appear at 22.3°, 27.5°, 30.5°, 47.3°, 52.5° and 55.7° for the sample of sulfur indium zinc nanosized flower cluster microspheres, corresponding to the (006), (102), (104), (110), (116) and (022) crystal planes of ZnIn2S4 respectively, indicating that the prepared sulfur indium zinc nanosized flower cluster microspheres are all ZnIn2S4 with a hexagonal phase structure (JCPDS No. 65-2023). The diffraction peaks of ZIS gradually weaken with the increase of the composite amount after compounding with CoPC. The absence of obvious diffraction peaks in CoPC may be due to the poor crystallinity of argon phosphating at 300 °C. In addition, the diffraction peaks of ZIF-67 appearing in the 10-20° region of CoPC indicate that ZIF-67 is not completely phosphated during the phosphating process and a part of carbon element is retained.

[0100] (2) To evaluate the influence of the CoPC cocatalyst on the electrochemical reaction in the photocatalytic reaction of the ZIS material. The sulfur indium zinc nanosized flower cluster microspheres (ZIS) of Comparative Example 1, CoPC of Comparative Example 2, and Z 70 -CoPC 30 of Example 1, Z 50 -CoPC 50 of Example 2, and Z 30 -CoPC 70 of Example 3 were respectively drop-coated on FTO glass slides as the photoanode, a 1 cm 2 platinum sheet was used as the counter electrode, and an Ag / AgCl electrode was used as the reference electrode. The photocurrent density was measured by linear sweep voltammetry under AM 1.5G light power of 100 mW·cm -2 light irradiation, and the results are as shown in Figure 3 . The linear sweep voltammetry (LSV) measurement was carried out in the potential range of -0.4 to 1.75 V (versus RHE).

[0101] It can be seen from Figure 3 that in an environment with a pH value of 6, the ZIS / CoPC composite material exhibits a photocurrent density of 175 μA·cm - 2 at -0.24 V (versus RHE), which is the original ZIS (34 μA·cm -5 times that of pure CoPC (11.7 μA·cm at 2, -0.24 V vs. RHE), and 15 times that of pure CoPC (at 2, -0.24 V vs. RHE). The significant improvement in the photocurrent density of the ZIS / CoPC composite indicates its excellent charge separation and transfer capabilities, which are crucial for efficient photocatalytic applications. The significant increase in photocurrent can be attributed to the enhanced charge separation mechanism, enabling ZIS / CoPC to exhibit remarkable light response. - 5 times that of pure CoPC (11.7 μA·cm at 2, -0.24 V vs. RHE), and 15 times that of pure CoPC (at 2, -0.24 V vs. RHE). The significant improvement in the photocurrent density of the ZIS / CoPC composite indicates its excellent charge separation and transfer capabilities, which are crucial for efficient photocatalytic applications. The significant increase in photocurrent can be attributed to the enhanced charge separation mechanism, enabling ZIS / CoPC to exhibit remarkable light response.

[0102] (3) Put the zinc indium sulfide nanosheet cluster microspheres (ZIS) of Comparative Example 1, CoPC of Comparative Example 2, Z 70 -CoPC 30 of Example 1, Z 50 -CoPC 50 of Example 2, and Z 30 -CoPC 70 into a quartz reactor and conduct a hydrogen production test under 10 W full spectrum (simulated sunlight) and visible light for 10 h under the same test conditions. Take samples every 2 h. During the test, use 10% (v / v) triethanolamine as a sacrificial agent under 10 W visible light conditions. The results are as Figure 4 shown.

[0103] As can be seen from Figure 4 , the hydrogen production rate of pure ZIS can reach 0.25 mmol·g -1 ·h -1 . When CoPC is combined with zinc indium sulfide nanosheet cluster microspheres, the hydrogen production rate is significantly improved. Among them, the photocatalytic hydrogen production rate of Z 50 -CoPC 50 reaches 21 mmol·g -1 (2.1 mmol·g -1 ·h -1 ), which is 7.4 times that of pure ZIS.

[0104] (4) Figure 5 are the scanning electron microscope images of the zinc indium sulfide nanosheet cluster microspheres (a) of Comparative Example 1, ZIF-67 and phosphated CoPC (b) of Comparative Example 2, Z 50 -CoPC 50 of Example 2 (c), and the EDS spectrum (d) of Z 50 -CoPC 50 of Example 2.

[0105] As can be seen from Figure 5 (a), the zinc indium sulfide nanosheet cluster microspheres are flower-like microspheres composed of countless intertwined zinc indium sulfide nanosheets (sheet diameter is 1 - 2 μm), with a diameter of 5 μm and a specific surface area of 45.93 m 2 / g.

[0106] From Figure 5 As can be seen from (b), CoPC loses the dodecahedral structure of the original cobalt-based metal-organic framework material (Co-MOFs) and becomes fragmented small particles (particle size: 500 - 1000 nm). This may be due to the structural collapse of Co-MOFs during argon annealing, resulting in fragmentation and dispersion.

[0107] From Figure 5 As can be seen from (c), the morphology of zinc indium sulfide remains basically unchanged after ultrasonic treatment, and small CoPC particles adhere to its surface.

[0108] From Figure 5 As can be seen from (d), EDS elemental mapping indicates the successful synthesis of Z 50 -CoPC 50 .

[0109] Although the above embodiments have described the present invention in detail, they are only a part rather than all of the embodiments of the present invention. People can also obtain other embodiments based on these embodiments without creative efforts, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A carbon-containing metal phosphide-indium zinc sulfide composite material, characterized in that: include: Indium zinc sulfide nanoflower cluster microspheres and carbon-containing metal phosphide nanoparticles; The sulfur indium zinc nano flower cluster microspheres are aggregates of sulfur indium zinc nanosheets, and the chemical composition of the sulfur indium zinc nanosheets is ZnIn2S4; The carbon-containing metal phosphide nanoparticles are loaded on the surface of the indium zinc sulfide nanosheets in the indium zinc sulfide nanoflower cluster microspheres.

2. The carbon-containing metal phosphide-indium zinc sulfide composite material according to claim 1, characterized in that: The metal element in the carbon-containing metal phosphide nanoparticles is one or more of Co, Cu and Ni.

3. The carbon-containing metal phosphide-indium zinc sulfide composite material according to claim 1, characterized in that: The particle size of the sulfur indium zinc nano flower cluster microspheres is 1 to 5 μm, and the specific surface area is 40 to 50 m 2 / g; the diameter of the sulfur indium zinc nanosheet is 1 to 2 μm; and the particle size of the carbon-containing metal phosphide nanoparticle is 500 to 1000 nm.

4. The carbon-containing metal phosphide-indium zinc sulfide composite material according to claim 1, characterized in that: The mass percentage of indium zinc sulfide nano flower cluster microspheres in the carbon-containing metal phosphide-indium zinc sulfide composite material is 30-70%, and the mass percentage of carbon-containing metal phosphide nanoparticles is 30-70%.

5. The method for preparing the carbon-containing metal phosphide-indium zinc sulfide composite material according to any one of claims 1 to 4, characterized in that: The following steps are involved: Annealing the metal organic framework material and sodium hypophosphite in a protective gas to obtain carbon-containing metal phosphide nanoparticles; The carbon-containing metal phosphide nanoparticles and indium zinc sulfide nanoflower cluster microspheres are mixed and loaded in a polar solvent to obtain the carbon-containing metal phosphide-indium zinc sulfide composite material.

6. The preparation method according to claim 5, characterized in that: The annealing temperature is 270-330° C., and the insulation time is 1-3 hours.

7. The preparation method according to claim 5, characterized in that: The loading method is ultrasonic treatment; the power of the ultrasonic treatment is 80-120W, the temperature is 20-30°C, and the time is 10-20min.

8. The preparation method according to claim 5, characterized in that: The method for preparing the sulfur-indium-zinc nano-flower cluster microspheres comprises the following steps: subjecting a precursor solution to a solvothermal reaction to obtain sulfur-indium-zinc nano-flower cluster microspheres, wherein the precursor solution comprises zinc salt, indium salt, sulfur-containing substance and alcohol aqueous solution.

9. Use of the carbon-containing metal phosphide-indium zinc sulfide composite material according to any one of claims 1 to 4 or the carbon-containing metal phosphide-indium zinc sulfide composite material prepared by the preparation method according to any one of claims 5 to 8 as a photocatalyst.

10. A method for producing hydrogen by photocatalytic decomposition of water, characterized in that: The following steps are involved: The aqueous solution containing the photocatalyst is subjected to photolysis and catalytic hydrogen production under light to obtain hydrogen gas; The photocatalyst is the carbon-containing metal phosphide-indium zinc sulfide composite material as described in any one of claims 1 to 4 or the carbon-containing metal phosphide-indium zinc sulfide composite material prepared by the preparation method as described in any one of claims 5 to 8.

Images