A composite photocatalyst and its preparation and application

Abstract

This invention relates to the preparation and application of main catalysts with different morphologies and their composite photocatalysts. The preparation steps of the composite catalyst are as follows: TiVAlC is added to three different morphologies of ZnIn2S4, followed by ethanol addition, stirring, sonication, impregnation, evaporation, and grinding to obtain the target product TiVAlC / ZnIn2S4. The advantages of this invention are: fewer preparation conditions, simple process, and low cost. This photocatalyst can be applied to the field of photocatalytic water splitting for hydrogen production, and it significantly improves the hydrogen production rate of photocatalytic water splitting for hydrogen production.

Description

Technical Field

[0001] This invention relates to the preparation and application of three different morphologies of ZnIn2S4 and TiVAlC / ZnIn2S4 composite photocatalysts. These composite photocatalysts exhibit high photocatalytic hydrogen production rates through water splitting and hold promise for applications in other fields. Background Technology

[0002] Currently, the world faces two major problems: insufficient energy supply and environmental pollution, which seriously hinder human development and survival. How to rationally solve these two problems is crucial to achieving sustainable development. Scientific researchers have discovered that using sunlight to irradiate photocatalysts for water splitting to produce hydrogen is one of the most ideal methods to solve these two problems.

[0003] Different morphologies of semiconductors have a significant impact on their photocatalytic hydrogen production performance. Engineering the bulk, surface, and interface structures of semiconductors can significantly increase the separation and transport efficiency of photoexcited electrons and holes. Adjusting the unique morphology of semiconductor photocatalysts can affect the separation and transport efficiency of photogenerated carriers, thereby influencing photocatalytic hydrogen production performance.

[0004] In research on photocatalytic water splitting for hydrogen production, researchers have found that after photoexcitation, the photogenerated electrons easily recombine with holes, and the photocatalyst exhibits photocorrosion, severely affecting the efficiency of photocatalytic water splitting for hydrogen production. To address this, co-catalysts are used to reduce electron-hole recombination in the photocatalyst, enabling effective separation of photogenerated electrons and holes, increasing the number of reactive sites, and enhancing the photocatalytic hydrogen production activity. Summary of the Invention

[0005] The purpose of this invention is to compare the hydrogen production activity of ZnIn2S4 with different morphologies and the improvement rate of hydrogen production rate by photocatalytic water splitting after loading TiVAlC onto the composite catalyst.

[0006] Technical solution of the present invention

[0007] The preparation methods of three different morphologies of ZnIn2S4 and TiVAlC / ZnIn2S4 composite photocatalysts are as follows: 1) Using ZnCl2 and Zn(NO3)2·6H2O as zinc sources, InCl3·4H2O and In(NO3)·4.5H2O as indium sources, and TAA and thiourea as sulfur sources, three different morphologies of ZnIn2S4 are prepared by hydrothermal method with different raw material formulations; 2) TiVAlC is loaded on the three different morphologies of ZnIn2S4 by ultrasonication, impregnation, stirring, evaporation and grinding to obtain TiVAlC / ZnIn2S4 composite catalyst.

[0008] A composite photocatalyst, characterized in that:

[0009] It is composed of TiVAlC loaded with ZnIn2S4, with the mass ratio of TiVAlC to ZnIn2S4 being 12-23%, preferably 18-22%, and more preferably 19-21%.

[0010] The ZnIn2S4 is one or more of three different morphologies of ZnIn2S4 photocatalysts: spherical ZnIn2S4-S, blocky ZnIn2S4-B, and rod-shaped ZnIn2S4-R.

[0011] 12–25 mg (preferably 18–22 mg, more preferably 19–21 mg) of TiVAlC and 0.1 g of ZnIn2S4 are added to an open container containing 9–20 ml (preferably 12–18 ml, more preferably 15–16 ml) of dispersant (which may be one or more of ethanol, water, or methanol). The mixture is stirred at a rate of 100–800 r / min (preferably 300–600 r / min, more preferably 500–600 r / min) until dry, and then ground into powder to obtain the TiVAlC / ZnIn2S4 composite photocatalyst.

[0012] The specific preparation process of ZnIn2S4-S is as follows: 0.0562–0.1864 g (preferably 0.0967–0.1523 g, more preferably 0.13628 g–0.1473 g) of ZnCl2, 0.1465–1.327 g (preferably 0.3824–0.9369 g, more preferably 0.5844 g–0.6834 g) of InCl3·4H2O, and 0.1805–1.372 g (preferably 0.4736–0.8760 g, more preferably 0.60104 g–0.7613 g) of thioacetamide (… TAA was dissolved in 10-120 mL (preferably 30-80 mL, more preferably 40-55 mL) of distilled water; after stirring for 5-80 minutes (preferably 20-50 minutes, more preferably 30-45 minutes), the mixture was transferred to a hydrothermal reactor lined with polytetrafluoroethylene material and heated at 120-240°C (preferably 160-200°C, more preferably 180-190°C) for 13-27 h (preferably 15-21 h, more preferably 18-20 h). The mixture was centrifuged, and the precipitate was washed successively with distilled water and ethanol, and dried to obtain ZnIn2S4-S powder.

[0013] The specific process for preparing ZnIn2S4-B is as follows: Add 0.02763–1.432 g (preferably 0.0652–0.1703 g, more preferably 0.0892–0.0953 g) of Zn(NO3)2·6H2O and 0.0538–0.7491 g (preferably 0.1381–0.3961 g, more preferably 0.2291–0.2562 g) of In(NO3)·4.5H2O to 10–12 ml (preferably 4–9 ml) of deionized water, stirring until the solid is completely dissolved. Then add 3–12 ml (preferably 4–9 ml) of [the remaining water]. Add 0.1295–0.2273 g (preferably 0.1593–0.2056 g, more preferably 0.1803–0.1956 g) of TAA to the mixture, and stir continuously for 1–13 h (preferably 1.5–5 h, more preferably 2–4 h). Then, transfer the mixture to a hydrothermal reactor lined with polytetrafluoroethylene material and heat at 120–240 °C (preferably 140–190 °C, more preferably 160–180 °C) for 2–13 h (preferably 3–8 h, more preferably 6–7 h). Centrifuge, wash the precipitate with distilled water and ethanol, and dry to obtain ZnIn2S4-B.The specific process for preparing ZnIn2S4-R is as follows: 2–8 mg (preferably 3–6 mg, more preferably 4.5–5 mg) of In(NO3)·4.5H2O and 1–10 mg (preferably 3–6 mg, more preferably 4.5–5.5 mg) of terephthalic acid (H2BDC) are dispersed in 1–9 mL (preferably 1.5–4 mL, more preferably 2–3 mL) of DMF solution and heated at 70–160 °C (preferably 90–130 °C, more preferably 110–120 °C) for 10–70 min (preferably 20–55 min, more preferably 30–40 min); then, the white precipitate of MIL-68(In) is collected by centrifugation, washed with ethanol, and finally dried at 30–100 °C (preferably 40–80 °C, more preferably 60–70 °C); then, 5–80 mg (preferably 10–40 mg, more preferably) of the prepared MIL-68(In) is added. 20–30 mg of ZnIn2S4-R powder was dispersed in 10–70 mL (preferably 20–40 mL, more preferably 30–35 mL) of ethanol solution, and then 300–1050 μL (preferably 500–900 μL, more preferably 750–800 μL) of 0.03–0.5 M (preferably 0.15–0.3 M, more preferably 0.1–0.2 M) ZnCl2 solution and 120–280 mg (preferably 160–220 mg, more preferably 200–210 mg) of thiourea were added and stirred until the thiourea was completely dissolved. The resulting mixture was then transferred to a Teflon-lined autoclave, sealed tightly, and heated at 140–230 °C (preferably 160–210 °C, more preferably 180–200 °C) for 1–7 h (preferably 2–6 h, more preferably 3–4 h). After cooling to room temperature, the product was collected by centrifugation, washed with ethanol, and dried to obtain ZnIn2S4-R powder.

[0014] The application of TiVAlC / ZnIn2S4 composite catalyst prepared by the composite catalyst preparation method as a catalyst or active component of the catalyst in the photocatalytic water splitting process for hydrogen production.

[0015] The photocatalytic water splitting for hydrogen production uses 420–800 nm visible light as the light source, with an illumination time of 0.5–4 h (preferably 0.7–2 h, more preferably 1–1.5 h).

[0016] The photocatalytic hydrogen production performance of the LabSolor-H2 photocatalytic water splitting hydrogen production system of Pofilai Technology Co., Ltd. was tested under the following conditions: the light source was a 100-600W (preferably 200-500W, more preferably 300-350W) xenon lamp in the visible light band; the operating current was 8-21mA (preferably 13-18mA, more preferably 15-17mA); the illumination time was 0.5-4h (preferably 0.7-2h, more preferably 1-1.5h); Ar gas was used as the carrier gas; and the hydrogen production was measured by gas chromatography equipped with a TDX-01 column and a TCD detector.

[0017] The specific steps are as follows:

[0018] (1) The specific process for preparing three different morphologies of ZnIn2S4 is as follows: 0.1362 g ZnCl2, 0.5864 g InCl3·4H2O, and 0.60104 g thioacetamide (TAA) were dissolved in 40 mL of distilled water. After stirring for 30 minutes, the mixture was transferred to a 100 mL Teflon liner, heated at 180 °C for 18 h, and the precipitate was washed with distilled water and ethanol and dried at 80 °C for 12 h to obtain ZnIn2S4-S. 0.0892 g of Zn(NO3)2·6H2O and 0.2291 g of In(NO3)4·4.5H2O were added to 35 mL of deionized water and stirred until the solids were completely dissolved. Then, 5 mL of TAA (0.1803 g) was added, and the mixture was stirred continuously for 2 h. The mixture was then transferred to a 100 mL Teflon liner and heated at 160 °C for 6 h. The precipitate was washed with distilled water and ethanol and dried at 50 °C for 48 h to obtain ZnIn2S4-B. 4.5 mg of In(NO3)4·4.5H2O and 5.5 mg of terephthalic acid (H2BDC) were dispersed in 2 mL of DMF solution and heated in an oil bath at 120 °C for 30 min. The white precipitate of MIL-68(In) was then collected by centrifugation, washed three times with ethanol, and finally dried in a vacuum oven at 60°C. 20 mg of the prepared MIL-68(In) was dispersed in 30 mL of ethanol solution, followed by the addition of (750 μL, 0.1 M) ZnCl2 solution and 200 mg of thiourea, and stirred until the thiourea was completely dissolved. The resulting mixture was then transferred to a Teflon-lined autoclave, sealed tightly, and heated at 180°C for 3 hours. After naturally cooling to room temperature, the product was collected by centrifugation and washed three times with ethanol. The final product was dried in a vacuum oven at 60°C to obtain ZnIn2S4-R.

[0019] (2) The specific process for preparing TiVAlC / ZnIn2S4-S is as follows: Under strong stirring, TiVAlC and ZnIn2S4-B are weighed and added to a small beaker at a mass ratio of 20% (Wt%). 15ml of ethanol is measured with a graduated cylinder and added to the beaker. The mixture is then sonicated and stirred at a rate of 500r / min until completely dry. The dried catalyst is scraped off with a spatula and ground thoroughly into a uniform powder to obtain TiVAlC / ZnIn2S4-S powder.

[0020] (3) The specific process for preparing TiVAlC / ZnIn2S4-B is as follows: Weigh 20mg TiVAlC and 0.1g ZnIn2S4-B and dissolve them in 10ml of ethanol. Sonicate until the dispersion is uniform. Stir at a rate of 500r / min until completely dry. Scrape the dried catalyst off with a spatula and grind it thoroughly into a uniform powder to obtain TiVAlC / ZnIn2S4-B powder.

[0021] (4) The specific process for preparing TiVAlC / ZnIn2S4-R is as follows: Weigh 20mg TiVAlC and 0.1g ZnIn2S4-R and dissolve them in 10ml of ethanol. Sonicate until the dispersion is uniform, stir at a rate of 500r / min until completely dry, scrape the dried catalyst off with a spatula, and grind it thoroughly into a uniform powder to obtain TiVAlC / ZnIn2S4-R powder.

[0022] Test conditions: 90 mL deionized water, 10 mL lactic acid, 300 W xenon lamp in the visible light band as the light source, working current of 15 mA, illumination time of 1 h, and Ar gas as the carrier gas.

[0023] The advantages of this invention are: it utilizes TiVAlC and three different morphologies of ZnIn2S4 to form a binary composite photocatalyst, which has the advantages of simple preparation method, abundant reserves, and low cost. Tests show that the photocatalytic hydrogen production activity of TiVAlC / ZnIn2S4-S is 1.8 times that of ZnIn2S4-S alone in photocatalytic water splitting for hydrogen production. The photocatalytic hydrogen production activity of TiVAlC / ZnIn2S4-B is 2 times that of ZnIn2S4-B alone in photocatalytic water splitting for hydrogen production. The photocatalytic hydrogen production activity of TiVAlC / ZnIn2S4-R is 1.6 times that of ZnIn2S4-R alone in photocatalytic water splitting for hydrogen production.

[0024] The advantages of this invention are: fewer preparation conditions, simple process, and low price. This photocatalyst can be applied to the field of photocatalytic water splitting for hydrogen production, and the hydrogen production rate of photocatalytic water splitting for hydrogen production is significantly improved. Attached Figure Description

[0025] Figure 1The images show the XRD patterns of Examples 1, 2, and 3 (XRD patterns of ZnIn2S4 with different morphologies).

[0026] Figure 2 The images shown are the XRD patterns of Examples 4, 5, 6, 7, and 8 (XRD patterns of TiVAlC / ZnIn2S4-S). Figure 3 XRD patterns of TiVAlC cocatalyst and TiVAlC supported on ZnIn2S4 with different morphologies in Examples 6, 9, and 10 ( );

[0027] Figure 4 The activity graphs for Examples 1, 4, 5, 6, 7, and 8 (photocatalytic hydrogen production activity graphs of ZnIn2S4-S supported by different contents of TiVAlC);

[0028] Figure 5 The activity diagrams for Examples 1, 2, 3, 6, 9, and 10 (photocatalytic hydrogen production activity diagrams of ZnIn2S4 with different morphologies and its TiVAlC-supported form);

[0029] Figure 6 The images are scanning electron microscope images of Examples 1, 2, and 3 (SEM images of ZnIn2S4 with different morphologies: (a) ZnIn2S4-S, (b) ZnIn2S4-B, (c) ZnIn2S4-R).

[0030] Figure 7 Scanning electron microscope images of Examples 6, 9, and 10 (SEM images of TiVAlC cocatalyst and TiVAlC supported on ZnIn2S4 with different morphologies: (a) TiVAlC, (b) TiVAlC / ZnIn2S4-S, (c) TiVAlC / ZnIn2S4-B, (d) TiVAlC / ZnIn2S4-R); Detailed Implementation

[0031] The present invention will be further described in detail below through specific embodiments.

[0032] TiVAlC was purchased from Suzhou Beike Nanotechnology Co., Ltd.; it is a layered TiVAlC with a thickness of 0.1 to 0.5 μm and a surface that is a quadrilateral with a length and width of 0.5 to 3 μm.

[0033] The following examples illustrate the reaction conditions for photocatalytic water splitting to produce hydrogen.

[0034] The photocatalytic hydrogen production performance of the LabSolor-H2 photocatalytic water splitting hydrogen production system of Pofilai Technology Co., Ltd. was tested. Ar gas was used as the carrier gas, and the hydrogen production was measured by gas chromatography equipped with a TDX-01 column and a TCD detector.

[0035] Photocatalytic hydrogen production reaction: 0.1g of composite photocatalyst was added to a mixed solution of lactic acid and deionized water with a volume of 100mL, 90mL of deionized water solution, and 10mL of lactic acid solution. The lamp source was a 300W xenon lamp with a visible light band of 420-800nm, the working current was 15mA, and the illumination time was 1h.

[0036] Example 1:

[0037] Preparation of ZnIn2S4-S photocatalyst: 0.13628 g ZnCl2, 0.5844 g InCl3·4H2O, and 0.60104 g thioacetamide (TAA) were weighed and dissolved in 40 mL deionized water. After stirring for 30 minutes, the mixture was transferred to a 100 mL hydrothermal reactor lined with polytetrafluoroethylene and heated at 180 °C for 18 h. After cooling to room temperature, the mixture was centrifuged, and the precipitate was washed three times each with water and ethanol, dried at 80 °C for 12 h, and ground to obtain spherical ZnIn2S4-S powder. The photocatalytic hydrogen production performance was tested in a LabSolor-H2 photocatalytic water splitting hydrogen production system, and the photocatalytic water splitting hydrogen production rate was 159 μmol / h. -1 g -1 .

[0038] Example 2

[0039] Preparation of ZnIn2S4-B photocatalyst: 89.24 mg Zn(NO3)2·6H2O and 229.15 mg In(NO3)·4.5H2O were weighed and dissolved in 35 ml of deionized water. The mixture was stirred at room temperature until all the solids were dissolved. Then, 5 ml of TAA (180.31 mg) aqueous solution was added, and the mixture was stirred continuously for two hours. The mixture was transferred to a hydrothermal reactor lined with polytetrafluoroethylene and reacted at 160 °C for 6 h. After cooling to room temperature, the mixture was centrifuged and washed three times each with water and ethanol. The resulting precipitate was dried in a vacuum drying oven at 50 °C for 48 h. After grinding, irregularly shaped (block-like) ZnIn2S4-B powder was obtained. The photocatalytic hydrogen production performance was tested in a LabSolor-H2 photocatalytic water splitting hydrogen production system, and the photocatalytic water splitting hydrogen production rate was 81 μmol / h. -1 g -1 .

[0040] Example 3:

[0041] Preparation of ZnIn2S4-R photocatalyst: 4.5 mg In(NO3)·4.5H2O and 5.5 mg terephthalic acid (H2BDC) were weighed and dispersed in 2 mL DMF solution, and heated in an oil bath at 120 °C for 30 min. The white precipitate of MIL-68(In) was then collected by centrifugation, washed three times with ethanol, and finally dried in a vacuum oven at 60 °C. 20 mg of the prepared MIL-68(In) was then weighed and dispersed in 30 mL ethanol solution, followed by the addition of (750 μL, 0.1 M) ZnCl2 solution and 200 mg thiourea, and stirred until the thiourea was completely dissolved. The resulting mixture was then transferred to a Teflon-lined autoclave, sealed tightly, and heated at 180 °C for 3 hours. After naturally cooling to room temperature, the product was collected by centrifugation and washed three times with ethanol. The final product was dried in a vacuum oven at 60 °C to obtain rod-shaped ZnIn2S4-R. The photocatalytic hydrogen production performance of the LabSolor-H2 photocatalytic water splitting hydrogen production system was tested, and the photocatalytic water splitting hydrogen production rate was 71 μmol / h. -1 g -1

[0042] Example 4:

[0043] Preparation of TiVAlC / ZnIn2S4-S composite photocatalyst: Weigh 0.1g ZnIn2S4-S and 12mg TiVAlC into an open container (beaker) containing 15mL of anhydrous ethanol solution and sonicate for 10min to disperse evenly. Stir the above solution at 500r / min to evaporate the ethanol. Grind the dried mixture into a uniform powder to obtain a TiVAlC / ZnIn2S4-S composite photocatalyst with a TiVAlC loading of 12% (Wt) relative to ZnIn2S4-S.

[0044] The photocatalytic hydrogen production performance of the LabSolor-H2 photocatalytic water splitting hydrogen production system was tested, and the photocatalytic water splitting hydrogen production rate was 195 μmol / h. -1 g -1 (Hydrogen μmol / h·g catalyst, the same below).

[0045] Example 5:

[0046] The process and conditions were the same as in Example 4, except that the amount of TiVAlC added was 15 mg, resulting in a TiVAlC / ZnIn2S4-S composite photocatalyst with a TiVAlC loading of 18% (Wt) relative to ZnIn2S4-S.

[0047] The photocatalytic hydrogen production performance of the LabSolor-H2 photocatalytic water splitting hydrogen production system was tested, and the photocatalytic water splitting hydrogen production rate was 248 μmol / h. -1 g -1.

[0048] Example 6:

[0049] The process and conditions were the same as in Example 4, except that the amount of TiVAlC added was 20 mg, resulting in a TiVAlC / ZnIn2S4-S composite photocatalyst with a TiVAlC loading of 20% (Wt) relative to ZnIn2S4-S.

[0050] The photocatalytic hydrogen production performance of the LabSolor-H2 photocatalytic water splitting hydrogen production system was tested, and the photocatalytic water splitting hydrogen production rate was 285 μmol / h. -1 g -1 .

[0051] Example 7:

[0052] The process and conditions were the same as in Example 4, except that the amount of TiVAlC added was 22 mg, resulting in a TiVAlC / ZnIn2S4-S composite photocatalyst with a TiVAlC loading of 22% (Wt) relative to ZnIn2S4-S.

[0053] The photocatalytic hydrogen production performance of the LabSolor-H2 photocatalytic water splitting hydrogen production system was tested, and the photocatalytic water splitting hydrogen production rate was 173 μmol / h. -1 g -1 .

[0054] Example 8:

[0055] The process and conditions were the same as in Example 4, except that the amount of TiVAlC added was 25 mg, resulting in a TiVAlC / ZnIn2S4-S composite photocatalyst with a TiVAlC loading of 25% (Wt) relative to ZnIn2S4-S.

[0056] The photocatalytic hydrogen production performance of the LabSolor-H2 photocatalytic water splitting hydrogen production system was tested, and the photocatalytic water splitting hydrogen production rate was 170 μmol / h. -1 g -1 .

[0057] Example 9:

[0058] Preparation of TiVAlC / ZnIn2S4-B composite photocatalyst: Weigh 0.1g ZnIn2S4-B and 18mg TiVAlC into an open container (beaker) containing 15mL of anhydrous ethanol solution and sonicate for 10min to disperse evenly. Stir the above solution at 500r / min to evaporate the ethanol. Grind the dried mixture into a uniform powder to obtain a TiVAlC / ZnIn2S4-B composite photocatalyst with a TiVAlC loading of 18% (Wt) relative to ZnIn2S4-B.

[0059] The photocatalytic hydrogen production performance of the LabSolor-H2 photocatalytic water splitting hydrogen production system was tested, and the photocatalytic water splitting hydrogen production rate was 136 μmol / h. -1 g -1 .

[0060] Example 10:

[0061] Preparation of TiVAlC / ZnIn2S4-B composite photocatalyst: Weigh 0.1g ZnIn2S4-B and 20mg TiVAlC into an open container (beaker) containing 15mL of anhydrous ethanol solution and sonicate for 10min to disperse evenly. Stir the above solution at 500r / min to evaporate the ethanol. Grind the dried mixture into a uniform powder to obtain a TiVAlC / ZnIn2S4-B composite photocatalyst with a TiVAlC loading of 20% (Wt) relative to ZnIn2S4-B.

[0062] The photocatalytic hydrogen production performance of the LabSolor-H2 photocatalytic water splitting hydrogen production system was tested, and the photocatalytic water splitting hydrogen production rate was 162 μmol / h. -1 g -1 .

[0063] Example 11:

[0064] Preparation of TiVAlC / ZnIn2S4-B composite photocatalyst: Weigh 0.1g ZnIn2S4-B and 22mg TiVAlC into an open container (beaker) containing 15mL of anhydrous ethanol solution and sonicate for 10min to disperse evenly. Stir the above solution at 500r / min to evaporate the ethanol. Grind the dried mixture into a uniform powder to obtain a TiVAlC / ZnIn2S4-B composite photocatalyst with a TiVAlC loading of 22% (Wt) relative to ZnIn2S4-B.

[0065] The photocatalytic hydrogen production performance of the LabSolor-H2 photocatalytic water splitting hydrogen production system was tested, and the photocatalytic water splitting hydrogen production rate was 117 μmol / h. -1 g -1 .

[0066] Example 12:

[0067] Preparation of TiVAlC / ZnIn2S4-R composite photocatalyst: Weigh 0.1g ZnIn2S4-R and 18mg TiVAlC into an open container (beaker) containing 15mL of anhydrous ethanol solution and sonicate for 10min to disperse evenly. Stir the above solution at 500r / min to evaporate the ethanol. Grind the dried mixture into a uniform powder to obtain a TiVAlC / ZnIn2S4-R composite photocatalyst with a TiVAlC loading of 18% (Wt) relative to ZnIn2S4-R.

[0068] The photocatalytic hydrogen production performance of the LabSolor-H2 photocatalytic water splitting hydrogen production system was tested, and the photocatalytic water splitting hydrogen production rate was 94 μmol / h. -1 g -1 .

[0069] Example 13:

[0070] Preparation of TiVAlC / ZnIn2S4-R composite photocatalyst: Weigh 0.1g ZnIn2S4-R and 20mg TiVAlC into an open container (beaker) containing 15mL of anhydrous ethanol solution and sonicate for 10min to disperse evenly. Stir the above solution at 500r / min to evaporate the ethanol. Grind the dried mixture into a uniform powder to obtain a TiVAlC / ZnIn2S4-R composite photocatalyst with a TiVAlC loading of 20% (Wt) relative to ZnIn2S4-R.

[0071] The photocatalytic hydrogen production performance of the LabSolor-H2 photocatalytic water splitting hydrogen production system was tested, and the photocatalytic water splitting hydrogen production rate was 119 μmol / h. -1 g -1 .

[0072] Example 14:

[0073] Preparation of TiVAlC / ZnIn2S4-R composite photocatalyst: Weigh 0.1g ZnIn2S4-R and 22mg TiVAlC into an open container (beaker) containing 15mL of anhydrous ethanol solution and sonicate for 10min to disperse evenly. Stir the above solution at 500r / min to evaporate the ethanol. Grind the dried mixture into a uniform powder to obtain a TiVAlC / ZnIn2S4-R composite photocatalyst with a TiVAlC loading of 22% (Wt) relative to ZnIn2S4-R.

[0074] The photocatalytic hydrogen production performance of the LabSolor-H2 photocatalytic water splitting hydrogen production system was tested, and the photocatalytic water splitting hydrogen production rate was 93 μmol / h.-1 g -1 .

[0075] The catalyst samples obtained in Examples 1, 2, and 3 were tested using an X-ray diffractometer. Figure 1 It can be seen that the characteristic peaks of the three different morphologies of ZnIn2S4 photocatalysts all correspond to the standard card PDF#48-1778, indicating that the catalysts were successfully prepared.

[0076] The catalyst samples obtained in Examples 4, 5, 6, and 7 were tested using an X-ray diffractometer. Figure 2 A distinct diffraction peak of TiVAlC at 40° was observed in the composite catalyst TiVAlC / ZnIn2S4-S, and a diffraction peak corresponding to that of ZnIn2S4 standard card PDF#48-1778 was also observed. This indicates that composite catalysts with different TiVAlC loadings were successfully prepared.

[0077] The catalyst samples obtained in Examples 1, 2, and 3 were tested using scanning electron microscopy. Figure 3 It can be seen that three different morphologies of ZnIn2S4 photocatalysts were successfully prepared: spherical ZnIn2S4 with a particle size of 0.6–0.85 μm, blocky (irregularly shaped) ZnIn2S4 with an equivalent diameter of 0.6–0.85 μm, and rod-shaped ZnIn2S4 with a cross-sectional diameter of 0.9–0.95 μm and a length of 0.8–1.2 μm.

[0078] The catalyst samples obtained in Examples 6, 9, and 10 were tested using scanning electron microscopy. Figure 7 As can be seen, layered TiVAlC with a thickness of 0.1–0.5 μm and a surface with a length and width of 0.5–3 μm quadrilaterals was successfully loaded onto ZnIn2S4 with three different morphologies, proving the successful preparation of the composite catalyst.

[0079] Example 11:

[0080] To test the photocatalytic hydrogen production performance of commercial TiVAlC: Weigh 0.1g TiVAlC and 10ml triethanolamine and place them in a photocatalytic hydrogen production glass container.

[0081] The photocatalytic hydrogen production performance of the LabSolor-H2 photocatalytic water splitting hydrogen production system was tested, and the photocatalytic water splitting hydrogen production rate was 0.

Claims

1. A composite photocatalyst, characterized in that: It is composed of TiVAlC loaded with ZnIn2S4, with a mass ratio of TiVAlC to ZnIn2S4 of 19-21%.

2. The composite photocatalyst according to claim 1, characterized in that: The ZnIn2S4 is one or more of three different morphologies of ZnIn2S4 photocatalysts: spherical ZnIn2S4-S, blocky ZnIn2S4-B, and rod-shaped ZnIn2S4-R.

3. A method for preparing the composite photocatalyst according to claim 1 or 2, characterized in that: Add 12-25 mg of TiVAlC and 0.1 g of ZnIn2S4 to an open container containing 9-20 ml of dispersant, which is one or more of ethanol, water or methanol. Stir at a rate of 100-800 r / min until dry, and grind into powder to obtain TiVAlC / ZnIn2S4 composite photocatalyst.

4. The preparation method according to claim 3, characterized in that: Add 18-22 mg of TiVAlC and 0.1 g of ZnIn2S4 to an open container containing 12-18 ml of dispersant, stir at 300-600 r / min until dry, and grind into powder to obtain TiVAlC / ZnIn2S4 composite photocatalyst.

5. The preparation method according to claim 3, characterized in that: The specific preparation process of ZnIn2S4-S is as follows: 0.0562~0.1864 g ZnCl2, 0.1465~1.327 g InCl3·4H2O, and 0.1805~1.372 g thioacetamide are dissolved in 10~120 mL of distilled water; after stirring for 5~80 minutes, the mixture is transferred to a hydrothermal reactor lined with polytetrafluoroethylene material and heated at 120~240℃ for 13~27 h. After centrifugation, the precipitate is washed successively with distilled water and ethanol, and dried to obtain ZnIn2S4-S powder.

6. The preparation method according to claim 5, characterized in that: The specific preparation process of ZnIn2S4-S is as follows: 0.0967~0.1523 g ZnCl2, 0.3824~0.9369 g InCl3·4H2O, and 0.4736~0.8760 g thioacetamide are dissolved in 30~80 ml of distilled water; after stirring for 20~50 minutes, the mixture is transferred to a hydrothermal reactor lined with polytetrafluoroethylene material, heated at 160~200℃ for 15~21 h, centrifuged, and the precipitate is washed successively with distilled water and ethanol, and dried to obtain ZnIn2S4-S powder.

7. The preparation method according to claim 3, characterized in that: The specific process for preparing ZnIn2S4-B is as follows: 0.02763~1.432 g of Zn(NO3)2·6H2O and 0.0538~0.7491 g of In(NO3)·4.5H2O are added to 10~65 ml of deionized water and stirred until the solid is completely dissolved. Then, 3~12 ml of thioacetamide is added and stirred continuously for 1~13 h. The mixture is then transferred to a hydrothermal reactor lined with polytetrafluoroethylene material and heated at 120~240℃ for 2~13 h. After centrifugation, the precipitate is washed with distilled water and ethanol and dried to obtain ZnIn2S4-B.

8. The preparation method according to claim 7, characterized in that: The specific process for preparing ZnIn2S4-B is as follows: 0.0652-0.1703 g of Zn(NO3)2·6H2O and 0.1381-0.3961 g of In(NO3)·4.5H2O are added to 20-50 ml of deionized water and stirred until the solids are completely dissolved. Then, 4-9 ml of 0.1593-0.2056 g of thioacetamide is added, and the mixture is stirred continuously for 1.5-5 h. The mixture is then transferred to a hydrothermal reactor lined with polytetrafluoroethylene material and heated at 140-190℃ for 3-8 h. After centrifugation, the precipitate is washed with distilled water and ethanol and dried to obtain ZnIn2S4-B.

9. The preparation method according to claim 3, characterized in that: The specific process for preparing ZnIn2S4-R is as follows: 2-8 mg In(NO3)·4.5H2O and 1-10 mg terephthalic acid are dispersed in 1-9 mL DMF solution and heated at 70-160℃ for 10-70 min; then, the white precipitate of MIL-68(In) is collected by centrifugation, washed with ethanol, and finally dried at 30-100℃; 5-80 mg of the prepared MIL-68(In) is dispersed in 10-70 mL ethanol solution, and then 300-1050 μL of 0.03-0.5 M ZnCl2 solution and 120-280 mg of thiourea are added and stirred until the thiourea is completely dissolved; then the resulting mixture is transferred to a Teflon-lined autoclave, sealed tightly, and heated at 140-230℃ for 1-7 h; after cooling to room temperature, the product is collected by centrifugation, washed with ethanol, and dried to obtain ZnIn2S4-R powder.

10. The preparation method according to claim 9, characterized in that: The specific process for preparing ZnIn2S4-R is as follows: 3-6 mg In(NO3)·4.5H2O and 3-6 mg terephthalic acid are dispersed in 1.5-4 mL DMF solution and heated at 90-130℃ for 20-55 min; then, the white precipitate of MIL-68(In) is collected by centrifugation, washed with ethanol, and finally dried at 40-80℃; 10-40 mg of the prepared MIL-68(In) is dispersed in 20-40 mL ethanol solution, and then 500-900 μL of 0.15-0.3 M ZnCl2 solution and 160-220 mg of thiourea are added and stirred until the thiourea is completely dissolved; then the resulting mixture is transferred to a Teflon-lined autoclave, sealed tightly, and heated at 160-210℃ for 2-6 h; after cooling to room temperature, the product is collected by centrifugation, washed with ethanol, and dried to obtain ZnIn2S4-R powder.

11. The application of the composite catalyst according to any one of claims 1 to 2 or the TiVAlC / ZnIn2S4 composite catalyst prepared by any one of the preparation methods according to claims 3 to 10 as a catalyst or the active component of a catalyst in the photocatalytic water splitting process for hydrogen production.

12. The application according to claim 11, characterized in that: The photocatalytic water splitting for hydrogen production uses 420-800nm ​​visible light as the light source and 0.5-4 hours of illumination.

13. The application according to claim 12, characterized in that: The photocatalytic hydrogen production performance of the LabSolor-H2 photocatalytic water splitting hydrogen production system of Pofilai Technology Co., Ltd. was tested under the following conditions: a 100-600W xenon lamp in the visible light band was used as the light source, the operating current was 8-21 mA, the illumination time was 0.5-4 h, Ar gas was used as the carrier gas, and the hydrogen production was measured by gas chromatography equipped with a TDX-01 column and a TCD detector.

14. The application according to claim 13, characterized in that: The test conditions were as follows: a 200-500 W xenon lamp in the visible light band was used as the light source, the working current was 13-18 mA, the illumination time was 0.7-2 h, Ar gas was used as the carrier gas, and the hydrogen production was measured by gas chromatography equipped with a TDX-01 column and a TCD detector.

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