An In2O3 / W 18 O 49 Preparation methods and applications of heterojunction nanofiber photocatalysts

Abstract

This invention belongs to the field of photocatalytic materials technology, specifically relating to an In2O3 / W 18 O 49 Preparation methods and applications of heterojunction nanofiber photocatalysts. In₂O₃ nanofibers prepared by high-voltage electrospinning are placed in W... 18 O 49 In2O3 / W synthesized by solvothermal reaction of precursor solution 18 O 49 Heterojunction nanofiber photocatalysts can be applied to the photocatalytic splitting of water for hydrogen evolution. Compared to existing photocatalysts, the In₂O₃ / W of this invention... 18 O 49 Heterojunction nanofiber photocatalysts have a large specific surface area, which can provide more reactive sites and help to further improve the carrier separation efficiency.

Description

Technical Field

[0001] This invention belongs to the field of photocatalytic materials technology, specifically relating to an In2O3 / W 18 O 49 Preparation methods and applications of heterojunction nanofiber photocatalysts. Background Technology

[0002] With the continuous growth of global energy consumption and the increasing severity of environmental pollution, finding clean and sustainable energy alternatives to traditional fossil fuels has become an urgent priority. Solar energy, as an inexhaustible and widely distributed clean energy source, has enormous potential. To develop clean and sustainable renewable energy, the photocatalytic splitting of water using solar energy to produce hydrogen has become a research hotspot. Photocatalytic water splitting to produce hydrogen is considered one of the most promising technologies for developing clean and sustainable hydrogen energy due to its advantages such as low cost, energy efficiency, and environmental friendliness. However, the efficiency of current photocatalysts for photocatalytic water splitting to produce hydrogen using solar energy is relatively low, making it difficult to meet human energy demands.

[0003] In₂O₃, due to its excellent conductivity, stability, wide bandgap, and low resistivity, is widely used in photocatalytic water splitting for hydrogen production. However, pure In₂O₃ faces challenges such as low solar energy utilization and high carrier complexation rate. Therefore, synthesizing heterojunctions is an effective method to improve the solar energy utilization of In₂O₃ and reduce electron-hole recombination. This invention introduces an In₂O₃ / W... 18 O 49 The formation of a heterojunction can improve the efficiency of photogenerated electron-hole separation, thereby enhancing photocatalytic activity; and In2O3 / W 18 O 49 There have been no reports yet on heterojunction nanofibers as photocatalysts for hydrogen evolution. Summary of the Invention

[0004] To address the above problems, this invention provides an In2O3 / W 18 O 49 Preparation methods and applications of heterojunction nanofiber photocatalysts.

[0005] The technical solution adopted in this invention is as follows:

[0006] An In2O3 / W 18 O 49 The preparation method of heterojunction nanofiber photocatalyst includes the following steps:

[0007] 1) Dissolve indium nitrate 4.5g water in a mixed solution of N,N-dimethylformamide and ethanol. After complete dissolution, add polyvinylpyrrolidone powder to the above mixed solution and stir until the solution is colorless and transparent. Electrospinning is performed at a voltage of 15kV and a distance of 12cm from the collecting plate to collect nanofibers.

[0008] 2) The collected nanofibers were torn apart with scissors and tweezers and placed in a porcelain boat. They were then calcined in a low-temperature muffle furnace to obtain In2O3 nanofibers.

[0009] 3) Dissolve tungsten hexachloride in anhydrous ethanol and stir until the solution turns blue. Place the In2O3 nanofibers obtained in step 2) in an autoclave containing the tungsten hexachloride solution for hydrothermal reaction. After the reaction is complete, wash and dry the sample to obtain In2O3 / W. 18 O 49 Heterojunction nanofiber photocatalyst.

[0010] Furthermore, in the above preparation method, in step 1), the amount of indium nitrate tetrapentahydrate is 0.8g, the amount of polyvinylpyrrolidone powder is 1g, the amount of N,N-dimethylformamide is 4mL, and the amount of ethanol is 6mL.

[0011] Furthermore, in the above preparation method, steps 1) and 3) involve stirring using a magnetic stirrer.

[0012] Furthermore, in the above preparation method, step 2), the calcination temperature is 550℃, the heating rate is 1℃ / min, and the calcination time is 2h.

[0013] Furthermore, in the above preparation method, in step 3), the mass ratio of tungsten hexachloride and In2O3 nanofibers is 5%, 25%, or 35%.

[0014] Furthermore, in the above preparation method, step 3), the hydrothermal reaction temperature is 160℃ and the reaction time is 6h.

[0015] Furthermore, in the above preparation method, step 3), the drying temperature is 40°C and the drying time is 2 hours.

[0016] In2O3 / W prepared by any of the above methods 18 O 49 Application of heterojunction nanofiber photocatalysts in photocatalytic water splitting and hydrogen evolution.

[0017] Furthermore, the above application is carried out using the following method: Take In2O3 / W 18 O 49Heterojunction nanofiber photocatalysts are uniformly dispersed in a mixed solution of deionized water, triethanolamine, and chloroplatinic acid. Argon gas is then continuously introduced into a container containing the mixed solution at a constant flow rate to create a relative vacuum environment. Under visible light irradiation, water is photocatalytically decomposed to produce hydrogen.

[0018] Furthermore, in the above applications, based on the solid-liquid ratio, In2O3 / W 18 O 49 Heterojunction nanofiber photocatalyst: deionized water: triethanolamine: chloroplatinic acid = 20 mg: 18 mL: 2 mL: 15 μL.

[0019] The beneficial effects of this invention are as follows:

[0020] 1. This invention utilizes electrospinning and solvothermal methods to prepare In2O3 / W 18 O 49 Heterojunction nanofiber photocatalysts have an ultra-long one-dimensional structure, which can improve the separation efficiency of charge carriers and enhance photocatalytic activity.

[0021] 2. The In2O3 / W prepared by this invention 18 O 49 Heterojunction nanofiber photocatalysts have a stronger ability to absorb visible light, which is an effective way to improve visible light photocatalytic activity.

[0022] 3. The In2O3 / W prepared by this invention 18 O 49 Heterojunction nanofiber photocatalysts exhibit good photocatalytic hydrogen evolution performance, and the method is simple to prepare, environmentally friendly and non-toxic, low-cost, and conducive to large-scale production. Attached Figure Description

[0023] Figure 1 For In2O3, W 18 O 49 In2O3 / W 18 O 49 X-ray diffraction pattern of heterojunction nanofiber photocatalyst.

[0024] Figure 2 For In2O3, W 18 O 49 In2O3 / W 18 O 49 Hydrogen production time curve of water splitting by heterojunction nanofiber photocatalyst. Detailed Implementation

[0025] Example 1

[0026] In2O3 / W 18 O 49The preparation method of heterojunction nanofiber photocatalyst is as follows:

[0027] 0.8 g of indium nitrate tetrapentahydrate was dissolved in a mixed solution of 4 mL N,N-dimethylformamide (DMF) and 6 mL ethanol, and stirred magnetically until completely dissolved. 1 g of polyvinylpyrrolidone powder (PVP) was added and stirred until colorless and transparent. The resulting solution was drawn into a plastic syringe and electrospun using a voltage of 15 kV and a needle tip distance of 12 cm from the collector. A dense nanofiber was collected on an aluminum foil using tweezers. The dense nanofiber was cut into 5 cm × 8 cm rectangular slices and placed in a ceramic boat. The boat was then calcined in a muffle furnace at 550 °C for 2 h (heating rate of 1 °C / min) to obtain In₂O₃ nanofibers. 7 mg of WCl6 was dissolved in 12 mL of anhydrous ethanol and magnetically stirred until the solution turned blue. Then, 20 mg of In2O3 nanofibers were added, and the mixture was placed in a hydrothermal reactor and reacted at 160 °C for 6 h. After naturally cooling to room temperature, the mixture was washed three times with deionized water and anhydrous ethanol, and dried at 40 °C for 2 h to obtain In2O3 / WCl6. 18 O 49 Heterojunction nanofiber photocatalyst.

[0028] Figure 1 In2O3 / W prepared in Example 1 18 O 49 X-ray diffraction pattern of heterojunction nanofiber photocatalyst. Characteristic diffraction peaks appear at 2θ = 21.6°, 30.8°, 35.5° and 51.0° and 60.9°, corresponding to the (211), (222), (400), (440), and (622) crystal planes, consistent with the In2O3 PDF standard card (PDF#88-2160). Characteristic diffraction peaks appear at 2θ = 23.28° and 48.02°, corresponding to the (010) and (020) crystal planes, consistent with the W... 18 O 49 Consistent with the PDF standard card (PDF#71-2450). When the two are combined... Figure 1 As can be seen, the peaks of both substances appear in the composite sample In2O3 / W. 18 O 49 The result indicates that the two substances have successfully combined.

[0029] Example 2

[0030] At room temperature and pressure, 20 mg of the In2O3 / W prepared in Example 1 was taken. 18 O 49The heterojunction nanofiber photocatalyst was uniformly dispersed in a mixed solution of 18 mL deionized water, 2 mL TEOA (triethanolamine), and 15 μL chloroplatinic acid. Argon gas was continuously introduced into the container containing the mixed solution at a constant flow rate (40 mL / min) to create a relative vacuum environment. The container was then irradiated with a xenon lamp. After every 30 min of irradiation, the upper gas layer was extracted from the container with a syringe, and the hydrogen concentration in the upper gas layer was measured using a gas chromatograph.

[0031] Figure 2 The graph shows the hydrogen production rate-time curve of the sample's photocatalytic water splitting. It can be seen that after 30 minutes of light irradiation, the In₂O₃ / W ratio... 18 O 49 The hydrogen production rate was 177.7 μmol / g, which is 14.3 times that of pure In₂O₃ and is higher than that of pure W. 18 O 49 3.8 times the amount of hydrogen produced.

Claims

1. An In₂O₃ / W 18 O 49 A method for preparing heterojunction nanofiber photocatalysts, characterized in that, Includes the following steps: 1) Dissolve indium nitrate 4.5g water in a mixed solution of N,N-dimethylformamide and ethanol. After complete dissolution, add polyvinylpyrrolidone powder to the above mixed solution and stir until the solution is colorless and transparent. Electrospinning is performed at a voltage of 15kV and a distance of 12cm from the collecting plate to collect nanofibers. 2) The collected nanofibers were torn apart with scissors and tweezers and placed in a porcelain boat. They were then calcined in a low-temperature muffle furnace to obtain In2O3 nanofibers. 3) Dissolve tungsten hexachloride in anhydrous ethanol and stir until the solution turns blue. Place the In2O3 nanofibers obtained in step 2) in an autoclave containing the tungsten hexachloride solution for hydrothermal reaction. After the reaction is complete, wash and dry the sample to obtain In2O3 / W. 18 O 49 Heterojunction nanofiber photocatalyst.

2. The preparation method according to claim 1, characterized in that, In step 1), the amount of indium nitrate 4.5g is used, the amount of polyvinylpyrrolidone powder is used is 1g, the amount of N,N-dimethylformamide is used is 4mL, and the amount of ethanol is 6mL.

3. The preparation method according to claim 1, characterized in that, In steps 1) and 3), the stirring method is to use a magnetic stirrer.

4. The preparation method according to claim 1, characterized in that, Step 2), the calcination temperature is 550℃, the heating rate is 1℃ / min, and the calcination time is 2h.

5. The preparation method according to claim 1, characterized in that, In step 3), the mass ratio of tungsten hexachloride to In2O3 nanofibers is 5%, 25%, or 35%.

6. The preparation method according to claim 1, characterized in that, In step 3), the temperature of the hydrothermal reaction is 160°C and the reaction time is 6 hours.

7. The preparation method according to claim 1, characterized in that, In step 3), the drying temperature is 40°C and the drying time is 2 hours.

8. In2O3 / W prepared by the preparation method according to any one of claims 1-7 18 O 49 Application of heterojunction nanofiber photocatalysts in photocatalytic water splitting and hydrogen evolution.

9. The application according to claim 8, characterized in that, The method is as follows: Take In2O3 / W 18 O 49 Heterojunction nanofiber photocatalysts are uniformly dispersed in a mixed solution of deionized water, triethanolamine, and chloroplatinic acid. Argon gas is then continuously introduced into a container containing the mixed solution at a constant flow rate to create a relative vacuum environment. Under visible light irradiation, water is photocatalytically decomposed to produce hydrogen.

10. The application according to claim 9, characterized in that, According to the solid-liquid ratio, In2O3 / W 18 O 49 Heterojunction nanofiber photocatalyst: deionized water: triethanolamine: chloroplatinic acid = 20 mg: 18 mL: 2 mL: 15 μL.

Images