Preparation method and application of W18O49 / Zn0. 1Cu0. 9InS2 heterojunction photocatalyst

Abstract

The invention relates to a preparation method and application of a W18O49 / Zn0. 1Cu0. 9InS2 heterojunction photocatalyst, and belongs to the technical field of photocatalytic materials. The W18O49 / Zn0. 1Cu0. 9InS2 photocatalyst is prepared by adopting a two-step hydrothermal method, and can be applied to the field of photocatalytic hydrogen evolution. Compared with the existing photocatalyst, the W18O49 / Zn0. 1Cu0. 9InS2 photocatalyst prepared by the invention has the advantages that the compounding of electron hole pairs can be reduced by doping Zn, and the photoelectron injection efficiency is improved. And the heterojunction is constructed, so that the separation efficiency of photon-generated carriers is improved, the light response capability of the material is remarkably improved, and the photocatalytic activity is enhanced. The method is green and environment-friendly, simple, convenient to operate and low in material preparation cost, conforms to the green and environment-friendly concept advocated at present, and has a wide application market prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of photocatalytic materials and particularly relates to a W 18 O 49 / Zn 0.1 Cu 0.9 InS 2 Preparation method and application of heterojunction photocatalyst. Background Art

[0002] Photocatalytic hydrogen evolution is a technology that uses light energy to decompose water to generate hydrogen. Due to its high efficiency and environmental protection, it has attracted widespread attention in recent years. With the growth of global energy demand and the intensification of environmental problems, hydrogen as a clean energy is regarded as an important alternative to fossil fuels. Compared with traditional hydrogen production methods, photocatalytic hydrogen evolution technology can not only utilize solar energy, a renewable resource, but also effectively solve problems such as high resource consumption and environmental pollution. This technology uses solar energy to catalyze water to decompose hydrogen through semiconductor photocatalysts, providing a green solution to future energy crisis problems.

[0003] Copper Indium Sulfide (CuInS 2 ) has the advantages of appropriate electronic band structure, excellent light absorption ability, environmental protection, stability and low cost, and is widely used in the field of visible light driven photocatalytic hydrogen evolution. 2 The band gap is narrow, the recombination efficiency of photogenerated carriers is high, and the efficiency of photocatalytic hydrogen production is low. Zn ion doping can improve CuInS 2 The surface chemical state can effectively enhance the photogenerated carrier density. 18 O 49 As a transition metal oxide, CuInS has a high specific surface area and abundant oxygen vacancies. 2 and W 18 O 49 The band structure of W is well matched. 18 O 49 / Zn 0.1 Cu 0.9 InS 2 Heterojunction photocatalytic materials can effectively inhibit the recombination of photogenerated electrons and holes, thereby improving the photocatalytic activity. 18 O 49 / Zn 0.1 Cu 0.9 InS 2 There are no reports on heterojunction photocatalysts acting on water to decompose hydrogen. Summary of the invention

[0004] The present invention provides a W 18 O 49 / Zn 0.1 Cu 0.9 InS 2 Preparation method and application of heterojunction photocatalyst.

[0005] The technical solution adopted by the present invention is:

[0006] A W 18 O 49 / Zn 0.1 Cu 0.9 InS 2 The preparation method of the heterojunction photocatalyst comprises the following steps:

[0007] 1) InCl 3 、CuSO 4 ·5H 2 O、NH 2 CSNH 2 Add them into a beaker containing N,N-dimethylformamide (DMF) in sequence, stir them thoroughly with a magnetic stirrer until they are dissolved, and then add ZnCl 2 Add to the above solution, stir for 30 minutes, transfer the resulting solution to an autoclave for hydrothermal reaction, wait until it is cooled to room temperature, centrifuge and wash the product, and place it in an oven to dry to obtain Zn 0.1 Cu 0.9 InS 2 Photocatalytic materials;

[0008] 2) WCl 6 Dissolve in anhydrous ethanol and add Zn 0.1 Cu 0.9 InS 2 , stirred, put into an autoclave for hydrothermal reaction, cooled naturally, centrifuged, washed and dried to obtain W 18 O 49 / Zn 0.1 Cu 0.9 InS 2 Heterojunction photocatalysts.

[0009] Furthermore, in the above-mentioned preparation method, in step 1), the InCl 3 、CuSO 4 ·5H 2 O、NH 2 CSNH 2 、ZnCl 2 The amounts used were 2mmol, 1.8mmol, 4.5mmol, and 0.2mmol respectively, and the amount of DMF used was 60mL.

[0010] Furthermore, in the above preparation method, in step 1), the temperature of the hydrothermal reaction is 180° C. and the reaction time is 24 h.

[0011] Further, in the above preparation method, in step 2), the amount of anhydrous ethanol used is 12 mL, WCl 6 The dosage is 0.2g, Zn 0.1 Cu 0.9 InS 2 The dosage is 0.05g.

[0012] Furthermore, in the above preparation method, in step 2), the temperature of the hydrothermal reaction is 160° C. and the reaction time is 6 hours.

[0013] Furthermore, in the above-mentioned preparation method, in step 1) and step 2), the centrifugal washing is performed by washing with deionized water twice and washing with anhydrous ethanol three times, the centrifugal speed is 8000 rpm, and the centrifugal time for each time is 10 minutes.

[0014] Furthermore, in the above-mentioned preparation method, in step 1) and step 2), the drying temperature is 60°C.

[0015] W prepared by any one of the preparation methods described above 18 O 49 / Zn 0.1 Cu 0.9 InS 2 Application of heterojunction photocatalysts in water splitting to produce hydrogen under light irradiation.

[0016] Further, the above application method is as follows: take W 18 O 49 / Zn 0.1 Cu 0.9 InS 2 The heterojunction photocatalyst was uniformly dispersed in a mixed solution of deionized water, triethanolamine and chloroplatinic acid. Argon gas was continuously introduced into the container containing the mixed solution at 40 mL / min to expel the air, and the reactor was sealed with an injection pad to decompose water to produce hydrogen under light conditions.

[0017] Furthermore, in the above application, the W 18 O 49 / Zn 0.1 Cu 0.9 InS 2 The amount of heterojunction photocatalyst used is 20 mg, the amount of deionized water used is 18 mL, the amount of triethanolamine used is 2 mL, and the amount of chloroplatinic acid used is 20 μL.

[0018] The beneficial effects of the present invention are:

[0019] 1. The present invention uses a two-step hydrothermal method to prepare a W 18 O 49 / Zn 0.1 Cu 0.9 InS 2 In heterojunction photocatalysts, Zn doping can reduce the recombination of electron-hole pairs and improve the photoelectron injection efficiency.

[0020] 2. W prepared by the present invention 18 O 49 / Zn 0.1 Cu 0.9 InS 2 Heterojunction photocatalysts, constructing heterojunctions improves the separation efficiency of photogenerated carriers, significantly improves the light response ability of the material, and enhances the photocatalytic activity.

[0021] 3. W prepared by the present invention 18 O 49 / Zn 0.1 Cu 0.9 InS 2 Heterojunction photocatalysts have good photocatalytic hydrogen evolution performance, and the method is simple, convenient, low-cost, mild in conditions, and conducive to large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The CuInS prepared in Example 1 2 Catalyst, Zn prepared in Example 2 0.1 Cu 0.9 InS 2 Catalyst, W prepared in Example 3 18 O 49 Catalyst, W prepared in Example 4 18 O 49 / CuInS 2 Catalyst and W of Example 5 18 O 49 / Zn 0.1 Cu 0.9 InS 2 X-ray 2θ=10°-80° diffraction pattern of heterojunction photocatalyst.

[0023] Figure 2 The CuInS prepared in Example 1 2 Catalyst, Zn prepared in Example 2 0.1 Cu 0.9 InS 2 Catalyst, W prepared in Example 4 18 O 49 / CuInS 2 Catalyst and W of Example 5 18 O49 / Zn 0.1 Cu 0.9 InS 2 X-ray 2θ=27.5°-28.5° diffraction pattern of heterojunction photocatalyst.

[0024] Figure 3 The CuInS prepared in Example 1 2 Catalyst, Zn prepared in Example 2 0.1 Cu 0.9 InS 2 Catalyst, W prepared in Example 3 18 O 49 Catalyst, W prepared in Example 4 18 O 49 / CuInS 2 Catalyst and W of Example 5 18 O 49 / Zn 0.1 Cu 0.9 InS 2 Schematic diagram of the photocatalytic hydrogen evolution activity of heterojunction photocatalyst.

[0025] Figure 4 The CuInS prepared in Example 1 2 Catalyst, Zn prepared in Example 2 0.1 Cu 0.9 InS 2 Catalyst, W prepared in Example 3 18 O 49 Catalyst, W prepared in Example 4 18 O 49 / CuInS 2 Catalyst and W of Example 5 18 O 49 / Zn 0.1 Cu 0.9 InS 2 Photoluminescence spectrum (PL) of heterojunction photocatalyst. DETAILED DESCRIPTION

[0026] Example 1

[0027] CuInS 2 The preparation method of the catalyst is as follows:

[0028] 2 mmol InCl 3 , 2mmolCuSO 4 ·5H 2 O, 4.5 mmol NH 2 CSNH 2, placed in a beaker containing 60 mL of DMF, stirred with a magnetic stirrer for 30 min, transferred to a 75 mL autoclave for hydrothermal reaction at 180 ° C for 24 h, cooled to room temperature, centrifuged at 8000 rpm, washed twice with deionized water and three times with anhydrous ethanol, each centrifugation time was 10 min, dried at 60 ° C, and ground to obtain CuInS 2 Photocatalyst.

[0029] Example 2

[0030] Zn 0.1 Cu 0.9 InS 2 The preparation method of the catalyst is as follows:

[0031] 2 mmol InCl 3 , 1.8 mmol CuSO 4 ·5H 2 O, 4.5 mmol NH 2 CSNH 2 , placed in a beaker containing 60 mL of DMF, stirred evenly by magnetic stirring, and then added 0.2 mmol of ZnCl 2 Stir for 30 min, transfer to a 75 mL autoclave and perform hydrothermal reaction at 180 ° C for 24 h. After cooling to room temperature, centrifuge at 8000 rpm, wash twice with deionized water and three times with anhydrous ethanol, each time for 10 min, dry at 60 ° C and grind to obtain Zn 0.1 Cu 0.9 InS 2 Photocatalyst.

[0032] Example 3

[0033] W 18 O 49 The preparation method of the catalyst is as follows:

[0034] 0.2 g WCl 6 , placed in a beaker containing 12 mL of ethanol, stirred with a magnetic stirrer for 20 min, transferred to a 15 mL autoclave and hydrothermally reacted at 160 ° C for 6 h, cooled to room temperature, centrifuged at 8000 rpm, washed twice with deionized water and three times with anhydrous ethanol, each centrifugation time was 10 min, dried and ground to obtain W 18 O 49 Photocatalyst.

[0035] Example 4

[0036] W 18 O 49 / CuInS 2 The preparation method of the catalyst is as follows:

[0037] 0.2gWCl 6 , placed in a beaker containing 12 mL of ethanol, and added the CuInS prepared in Example 1 2 0.05 g, stirred with a magnetic stirrer for 20 min, transferred to a 15 mL autoclave and hydrothermally reacted at 160 ° C for 6 h, cooled to room temperature, centrifuged at 8000 rpm, washed twice with deionized water and three times with anhydrous ethanol, each centrifugation time was 10 min, dried and ground to obtain W 18 O 49 / CuInS 2 Photocatalyst.

[0038] Example 5

[0039] W 18 O 49 / Zn 0.1 Cu 0.9 InS 2 The preparation method of the catalyst is as follows:

[0040] 0.2gWCl 6 , placed in a beaker containing 12 mL of ethanol, and added the Zn prepared in Example 2 0.1 Cu 0.9 InS 2 0.05 g, stirred with a magnetic stirrer for 20 min, transferred to a 15 mL autoclave and hydrothermally reacted at 160 ° C for 6 h, cooled to room temperature, centrifuged at 8000 rpm, washed twice with deionized water and three times with anhydrous ethanol, each centrifugation time was 10 min, dried and ground to obtain W 18 O 49 / Zn 0.1 Cu 0.9 InS 2 Photocatalyst.

[0041] Figure 1 The CuInS prepared in Example 1 2 Catalyst, Zn prepared in Example 2 0.1 Cu 0.9 InS 2 Catalyst, W prepared in Example 3 18 O 49 Catalyst, W prepared in Example 4 18 O 49 / CuInS 2 Catalyst and W of Example 5 18 O 49 / Zn 0.1 Cu 0.9 InS 2X-ray 2θ=10°-80° diffraction pattern of heterojunction photocatalyst. Figure 1 The characteristic diffraction peaks at 2θ = 27.9° and 46.5° correspond to the chalcopyrite structure CuInS 2 (1 1 2) and (2 0 4) crystal planes (JCPDS NO.85-1575), W 18 O 49 The characteristic peaks appearing on the surface correspond to the monoclinic structure W 18 O 49 (JCPDS NO.72-0478). CuInS can be observed in a series of composite samples. 2 and W 18 O 49 The characteristic peaks of W 18 O 49 / CuInS 2 Heterojunction photocatalyst was successfully prepared. Figure 2 The CuInS prepared in Example 1 2 Catalyst, Zn prepared in Example 2 0.1 Cu 0.9 InS 2 Catalyst, W prepared in Example 4 18 O 49 / CuInS 2 Catalyst and W of Example 5 18 O 49 / Zn 0.1 Cu 0.9 InS 2 X-ray 2θ = 27.5°-28.5° diffraction pattern of heterojunction photocatalyst. The sample after the introduction of Zn shows CuInS 2 The strongest diffraction peak shifts to a large angle, confirming the successful doping of Zn ions. Figure 1 and Figure 2 The results showed that W 18 O 49 / Zn 0.1 Cu 0.9 InS 2 Successful preparation of heterojunction photocatalyst.

[0042] Example 6

[0043] W 18 O 49 / Zn 0.1 Cu 0.9 InS 2 Application of heterojunction photocatalysts in catalytic decomposition of water and hydrogen evolution under light:

[0044] 1) Under normal temperature and pressure conditions, 20 mg of W prepared in Example 5 was added18 O 49 / Zn 0.1 Cu 0.9 InS 2 The heterojunction photocatalyst was placed in a reactor containing a mixed solution of 18 mL of deionized water, 2 mL of triethanolamine and 20 μL of chloroplatinic acid; argon gas was introduced into the reactor at a rate of 40 mL / min for 20 min to expel the air; under visible light irradiation, 1000 μL of gas in the reactor was extracted every 20 min, and the collected catalytic products were quantitatively analyzed using a gas chromatograph.

[0045] 2) Follow step 1) except that the W prepared in Example 5 18 O 49 / Zn 0.1 Cu 0.9 InS 2 The heterojunction photocatalysts were replaced with CuInS prepared in Example 1. 2 Catalyst, Zn prepared in Example 2 0.1 Cu 0.9 InS 2 Catalyst, W prepared in Example 3 18 O 49 Catalyst, W prepared in Example 4 18 O 49 / CuInS 2 The catalyst and other conditions remain unchanged, and the gases are taken respectively to measure the hydrogen production efficiency.

[0046] Figure 3 The graph is the relationship between hydrogen content and irradiation time. The peak area of ​​the extracted gas is measured by gas chromatograph and then converted into the amount of substance by calculation, such as Figure 3 As shown, after 2h, CuInS 2 The catalyst H 2 The yield was 149.21 μmol / g, W 18 O 49 The catalyst H 2 The yield was 6.66 μmol / g, and the activity was relatively low; Zn 0.1 Cu 0.9 InS 2 The catalyst H 2 The yield was 209.04 μmol / g, W 18 O 49 / CuInS 2 The catalyst H 2 The yield was 282.04 μmol / g, W 18 O 49 / Zn 0.1 Cu 0.9 InS2 Heterojunction photocatalyst H 2 The yield is 368.46 μmol / g, which is higher than CuInS 2 Catalyst and W 18 O 49 The catalyst was improved, indicating that ion doping and construction of heterostructures have strong redox capabilities.

[0047] Figure 4 The CuInS prepared in Example 1 2 Catalyst, Zn prepared in Example 2 0.1 Cu 0.9 InS 2 Catalyst, W prepared in Example 3 18 O 49 Catalyst, W prepared in Example 4 18 O 49 / CuInS 2 Catalyst and W of Example 5 18 O 49 / Zn 0.1 Cu 0.9 InS 2 PL spectra of heterojunction photocatalysts. 18 O 49 With the highest PL emission intensity, CuInS 2 It also has a relatively high emission intensity. 18 O 49 and CuInS 2 In comparison, all the remaining samples showed lower emission intensities, confirming that Zn doping and heterojunction construction effectively reduced the carrier transfer resistance and reduced charge recombination.

Claims

1. A W 18 O 49 / Zn 0.1 Cu 0.9 The preparation method of InS2 heterojunction photocatalyst is characterized in that: The following steps are involved: 1) InCl3, CuSO4·5H2O, and NH2CSNH2 were added to a beaker containing DMF in sequence, and stirred with a magnetic stirrer until dissolved. ZnCl2 was added to the above solution and stirred for 30 minutes. The resulting solution was transferred to an autoclave for hydrothermal reaction. After cooling to room temperature, the product was centrifuged and washed, and then dried in an oven to obtain Zn 0.1 Cu 0.9 InS2 photocatalytic material; 2) Dissolve WCl6 in anhydrous ethanol and add Zn 0.1 Cu 0.9 InS2, stirred, put into an autoclave for hydrothermal reaction, cooled naturally, centrifuged, washed and dried to obtain W 18 O 49 / Zn 0.1 Cu 0.9 InS2 heterojunction photocatalyst.

2. The preparation method according to claim 1, characterized in that: In step 1), the amounts of InCl3, CuSO4·5H2O, NH2CSNH2 and ZnCl2 are 2 mmol, 1.8 mmol, 4.5 mmol and 0.2 mmol respectively, and the amount of DMF is 60 mL.

3. The preparation method according to claim 1, characterized in that: In step 1), the temperature of the hydrothermal reaction is 180° C. and the reaction time is 24 h.

4. The preparation method according to claim 1, characterized in that: In step 2), the amount of anhydrous ethanol is 12 mL, the amount of WCl6 is 0.2 g, and the amount of Zn 0.1 Cu 0.9 The amount of InS2 used is 0.05g.

5. The preparation method according to claim 1, characterized in that: In step 2), the temperature of the hydrothermal reaction is 160° C. and the reaction time is 6 h.

6. The preparation method according to claim 1, characterized in that: In step 1) and step 2), the centrifugal washing is performed by washing twice with deionized water and three times with anhydrous ethanol, the centrifugal speed is 8000 rpm, and the centrifugal time for each time is 10 minutes.

7. The preparation method according to claim 1, characterized in that: In step 1) and step 2), the drying temperature is 60°C.

8. W prepared by the preparation method according to any one of claims 1 to 7 18 O 49 / Zn 0.1 Cu 0.9 Application of InS2 heterojunction photocatalyst in water decomposition to produce hydrogen under light irradiation.

9. The use according to claim 8, characterized in that: The method is as follows: Take W 18 O 49 / Zn 0.1 Cu 0.9 The InS2 heterojunction photocatalyst was uniformly dispersed in a mixed solution of deionized water, triethanolamine and chloroplatinic acid. Argon gas was continuously introduced into the container containing the mixed solution at 40 mL / min to expel the air, and the reactor was sealed with an injection pad to decompose water to produce hydrogen under light conditions.

10. The use according to claim 9, characterized in that: The W 18 O 49 / Zn 0.1 Cu 0.9 The amount of InS2 heterojunction photocatalyst used is 20 mg, the amount of deionized water used is 18 mL, the amount of triethanolamine used is 2 mL, and the amount of chloroplatinic acid used is 20 μL.

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