BN / CdS photocatalyst, preparation method thereof and application of BN / CdS photocatalyst in photocatalytic hydrogen production

Abstract

The invention belongs to the field of photocatalytic materials, and particularly relates to a BN / CdS photocatalyst, a preparation method thereof and application of the BN / CdS photocatalyst in photocatalytic hydrogen production. The preparation method of the BN / CdS photocatalyst comprises the following steps: adding a cadmium source, a sulfur source and boron nitride into a beaker, adding ethylenediamine into the beaker, violently stirring and fully mixing to obtain a suspension; transferring the turbid liquid into a reaction kettle for hydrothermal reaction, then cooling to room temperature, then centrifuging, washing and drying the obtained turbid liquid, and finally obtaining powder which is the composite photocatalyst material. The BN / CdS photocatalyst prepared by the invention has improved catalytic performance in photocatalytic hydrogen production reaction. In a given reaction system, under the irradiation of a xenon lamp and continuous illumination, the hydrogen generation rate reaches 264 [mu] mol / g / h and is increased by 3.3 times compared with a pure CdS catalyst.

Description

Technical Field

[0001] The invention belongs to the field of photocatalytic materials, and particularly relates to a BN / CdS photocatalyst and a preparation method thereof and application thereof in photocatalytic hydrogen production. Background Art

[0002] Photocatalysis is a technology that uses light energy to drive chemical reactions. Under the irradiation of light of a specific wavelength, photocatalysts can absorb light energy and oxidize or reduce substances adsorbed on the surface of the catalyst. Photocatalysts are one of them. Under the irradiation of light, they can promote chemical reactions without changing themselves, and convert light energy into the energy required for chemical reactions. The representative substance of photocatalysts is titanium dioxide (TiO2), which can produce antibacterial, deodorizing, oil decomposition, mildew and algae prevention, and air purification effects under the irradiation of sunlight or indoor fluorescent lamps. Photocatalysis technology was first discovered by Professor Akira Fujishima in 1967, when he found that titanium oxide could decompose water into oxygen and hydrogen under light. This discovery was known as the "Honda-Fujishima Effect". In 1972, Fujishima of Japan discovered the photocatalytic phenomenon, which gradually attracted the attention of the international research community. With the gradual improvement of global environmental awareness, photocatalysis technology is becoming a hot area of ​​scientific and technological innovation. It has the characteristics of high efficiency, environmental protection, and sustainability, and is widely used in air purification, water treatment, self-cleaning and other fields.

[0003] Although photocatalytic technology has shown great potential in many fields, it still faces some challenges, such as high preparation cost of photocatalysts and low light utilization rate. In the future, photocatalytic experimental equipment will pay more attention to technological innovation, including catalyst improvement, light source optimization and precise control of reaction conditions to improve catalytic efficiency and product selectivity. With the continuous development of technologies such as the Internet of Things and big data, photocatalytic experimental equipment will achieve intelligent control and improve experimental efficiency and data accuracy.

[0004] In short, as a green, efficient and sustainable technology, photocatalytic technology has broad application prospects and huge development potential. In the future, with the continuous advancement of technology and the continuous expansion of applications, photocatalytic technology will play a more important role in environmental protection, clean energy and other fields. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing a BN / CdS photocatalyst.

[0006] The technical solution adopted by the present invention is: a BN / CdS photocatalyst, the preparation method of which comprises the following steps:

[0007] 1) Add a cadmium source, a sulfur source and boron nitride into a beaker, then add ethylenediamine thereto, stir vigorously and mix thoroughly to obtain a suspension;

[0008] 2) After the stirring is completed, the suspension is transferred to a reactor for a hydrothermal reaction. After the reaction is completed, it is cooled to room temperature, and then the obtained suspension is centrifuged, washed, and dried. The final powder obtained is the composite photocatalyst material.

[0009] In the above-mentioned BN / CdS photocatalyst, in step 1), the sulfur source is thiourea.

[0010] In the above-mentioned BN / CdS photocatalyst, in step 1), the cadmium source is cadmium acetate dihydrate.

[0011] In the above-mentioned BN / CdS photocatalyst, in step 1), the molar ratio of cadmium source to sulfur source is 1:1.

[0012] In the above-mentioned BN / CdS photocatalyst, in step 2), the hydrothermal reaction is carried out at 160° C. for 24 hours.

[0013] In the above-mentioned BN / CdS photocatalyst, in step 2), the centrifugal speed is 8000 rpm.

[0014] In the above-mentioned BN / CdS photocatalyst, in step 2), the drying method is vacuum drying at 60°C.

[0015] Application of the above-mentioned BN / CdS photocatalyst in photocatalytic hydrogen production.

[0016] The above application method is as follows: in a sealed reaction tank, a water-acetonitrile-triethanolamine mixed solution is used as the reaction system, a xenon lamp is used as the light source to provide simulated sunlight, and the BN / CdS photocatalyst described in any one of claims 1-6 is used as a catalyst to produce hydrogen by photocatalysis.

[0017] The application is characterized in that the added amount of BN / CdS photocatalyst is 0.01 g, water is 4 mL, acetonitrile is 6 mL, and triethanolamine is 2 mL.

[0018] The triethanolamine is used as a hole sacrificial agent.

[0019] The beneficial effects of the present invention are as follows: the present invention adopts a one-step hydrothermal method to prepare a BN / CdS composite photocatalyst. The BN / CdS photocatalytic material provided by the present invention has high catalytic efficiency and rapid reaction. Under the irradiation of a xenon lamp and continuous illumination, the hydrogen generation rate reaches 264 μmol / g / h, which is 3.3 times higher than that of a pure CdS catalyst. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a transmission electron microscope image of BN photocatalytic material.

[0021] Figure 2 This is a transmission electron microscope image of CdS photocatalytic material.

[0022] Figure 3 This is a transmission electron microscope image of the BN / CdS photocatalytic composite material.

[0023] Figure 4 is the X-ray diffraction pattern (XRD) of BN / CdS photocatalytic material.

[0024] Figure 5 This is the infrared spectrum of BN / CdS photocatalytic material.

[0025] Figure 6 This is a diagram of the photocatalytic hydrogen production performance of BN / CdS photocatalytic material. DETAILED DESCRIPTION

[0026] In order to better understand the technical solution of the present invention, a specific embodiment is given to further illustrate it, but the solution is not limited thereto.

[0027] Example 1 The preparation method of BN / CdS photocatalyst (I) is as follows:

[0028] 1. Preparation of BN / CdS catalyst

[0029] Weigh 6mmol of cadmium acetate dihydrate, 6mmol of thiourea and 43.7mg of boron nitride into a glass beaker, add 60mL of ethylenediamine, and stir vigorously for 30min to mix the four thoroughly. Then, transfer them to a 100mL reactor for hydrothermal reaction at 160℃ for 1 day. After the reaction is completed, centrifuge the obtained suspension, wash, and vacuum dry at 60℃ overnight to obtain a composite catalyst.

[0030] Comparative Example 1BN photocatalytic material

[0031] BN is a commercially available drug and can be used directly after purchase without further purification.

[0032] Comparative Example 2 CdS photocatalytic material

[0033] Weigh 6 mmol of cadmium acetate dihydrate and 6 mmol of thiourea into a glass beaker, add 60 mL of ethylenediamine, and stir vigorously for 30 minutes to mix the three thoroughly. Then, transfer it to a 100 mL reactor for hydrothermal reaction at 160 ° C for 1 day. After the reaction is completed, the obtained suspension is centrifuged, washed, and vacuum dried at 60 ° C overnight to obtain CdS photocatalytic material.

[0034] Example 2 Detection

[0035] 1. Figure 1 , Figure 2 Transmission electron microscope images of BN and CdS photocatalytic materials, respectively. Figure 1 , Figure 2 It can be seen that the prepared CdS is a stacked nanorod-like structure; while BN shows aggregated particles.

[0036] 2. Figure 3 This is a transmission electron microscope image of the prepared BN / CdS photocatalytic material. Figure 3 It can be seen that the electron microscope image of the prepared catalyst shows both the aggregated granular morphology of boron nitride and the nanorod-like structure of cadmium sulfide. This result indicates the successful preparation of the composite material.

[0037] 3. Figure 4 is the X-ray diffraction spectrum (XRD) of the prepared BN / CdS photocatalytic material. Figure 4 It can be seen that no diffraction peak belonging to BN is obviously observed, but from the transmission electron microscopy image of the composite material ( Figure 3 ), both BN and CdS were observed in the sample, so no characteristic peak belonging to BN appeared, which may be due to the small amount of BN added and its excessive dispersion on CdS.

[0038] 4. Figure 5 This is the infrared spectrum of the prepared BN / CdS photocatalytic material. From the figure, we can see that the infrared spectrum of the composite material has both characteristic peaks belonging to BN and characteristic peaks of CdS, which once again proves the successful preparation of BN / CdS.

[0039] Example 3 Application of BN / CdS photocatalyst in photocatalytic hydrogen production

[0040] The xenon lamp of Zhongjiao Jinyuan was used to test the photocatalytic hydrogen production performance of the catalyst.

[0041] The method is as follows: a photocatalytic sealed reaction cell is used as a reactor, an inert gas is used for exhaust before the reaction, a mixed solution of 4 mL of water, 6 mL of acetonitrile, and 2 mL of triethanolamine is used as a reaction medium, a xenon lamp is used as a light source, and simulated sunlight is used as a radiation light, and the prepared 0.01 g of CdS and 0.01 g of BN / CdS are used as catalysts for photocatalytic hydrogen production, and the product is detected by gas chromatography. The hydrogen generation rate of the BN / CdS photocatalyst is 264 μmol / g / h.

[0042] like Figure 6The photocatalytic hydrogen production effect diagram of BN / CdS photocatalytic material is shown. From the figure, it can be seen that when a small amount of boron nitride is added during the synthesis of cadmium sulfide, the hydrogen production rate of the obtained composite catalyst increases by nearly 3.3 times, and the hydrogen generation rate reaches 264μmol / g / h. This shows that the addition of BN helps to improve the photocatalytic hydrogen production performance of CdS.

Claims

1. A BN / CdS photocatalyst, characterized in that: The preparation method comprises the following steps: 1) Add a cadmium source, a sulfur source and boron nitride into a beaker, then add ethylenediamine thereto, stir vigorously and mix thoroughly to obtain a suspension; 2) After the stirring is completed, the suspension is transferred to a reactor for a hydrothermal reaction. After the reaction is completed, it is cooled to room temperature, and then the obtained suspension is centrifuged, washed, and dried. The final powder obtained is the BN / CdS photocatalyst.

2. A BN / CdS photocatalyst according to claim 1, characterized in that: In step 1), the sulfur source is thiourea.

3. A BN / CdS photocatalyst according to claim 1, characterized in that: In step 1), the cadmium source is cadmium acetate dihydrate.

4. The BN / CdS photocatalyst according to claim 1, characterized in that: In step 1), the molar ratio of cadmium source to sulfur source is 1:

1.

5. The BN / CdS photocatalyst according to claim 1, characterized in that: In step 2), the hydrothermal reaction is carried out at 160° C. for 24 hours.

6. The BN / CdS photocatalyst according to claim 1, characterized in that: In step 2), the centrifugal speed is 8000 rpm.

7. The BN / CdS photocatalyst according to claim 1, characterized in that: In step 2), the drying method is vacuum drying at 60°C.

8. Use of the BN / CdS photocatalyst according to any one of claims 1 to 6 in photocatalytic hydrogen production.

9. The use according to claim 7, characterized in that: The method is as follows: in a sealed reaction tank, a water-acetonitrile-triethanolamine mixed solution is used as a reaction system, a xenon lamp is used as a light source to provide simulated sunlight, and the BN / CdS photocatalyst described in any one of claims 1 to 6 is used as a catalyst to produce hydrogen by photocatalysis.

10. The use according to claim 8, characterized in that: The added amount of BN / CdS photocatalyst is 0.01 g, water is 4 mL, acetonitrile is 6 mL, and triethanolamine is 2 mL.

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