V-nis2 microsphere attached with g-c3n4 composite photocatalyst and preparation method thereof

Abstract

This invention discloses a V-NiS2 microsphere-attached porous g-C3N4 composite photocatalyst and its preparation method. The preparation method includes: preparing porous g-C3N4 nanosheets; mixing nickel acetate, ammonium metavanadate, thiourea, and hexamethyltetraammonium in a molar ratio of (1-4):(0.5-3):(1-8):(1-5) to obtain a mixed powder; adding 60 mL of deionized water; sonicating for 45-125 min; and then sequentially adding 0.005-0.02 g of polypyrrole and 1-3 g of the product from step one. The prepared porous g-C3N4 nanosheets were thoroughly stirred, and then the mixture was quickly poured into the lining of a 100 mL reaction vessel. The reaction vessel was sealed and placed in an oven at 140–200 °C for 12–24 h. After the temperature in the oven dropped to room temperature, the reaction vessel was removed and cooled, then centrifuged, washed, dried, and ground to obtain the V-NiS2 / g-C3N4 photocatalyst. The obtained V-NiS2 / g-C3N4 photocatalyst has a stable structure, high hydrogen production efficiency, and its preparation conditions are simple and easy to control, with low production cost, making it easy to industrialize.

Description

Technical Field

[0001] This invention belongs to the field of functional materials technology, and relates to composite photocatalysts, specifically to a V-NiS2 microsphere-attached porous g-C3N4 composite photocatalyst and its preparation method. Background Technology

[0002] Solar energy, a green and inexhaustible source, has attracted widespread attention. With ongoing research, photocatalysis technology has been widely applied in hydrogen production, organic matter degradation, and synthesis. Finding photocatalysts with high catalytic activity, low cost, and abundant availability has become fundamental for the large-scale application of photocatalysis. Currently, developing novel composite photocatalytic materials using g-C3N4 nanosheets as the matrix is ​​an important way to improve the performance of photocatalytic hydrogen production. The g-C3N4 nanosheets, as the matrix, play a crucial role in the composite material. Therefore, in-depth comparative analysis of nanosheets obtained by different preparation methods, determining their advantages and disadvantages, is of great significance for further development of novel composite photocatalytic materials. In the research on visible light photocatalytic hydrogen production using g-C3N4 semiconductors, co-catalysts are needed to further enhance the catalytic activity of the samples. To date, most co-catalysts are rare and expensive metals, resulting in high costs. Therefore, developing abundant and inexpensive co-catalysts to improve the photocatalytic activity of g-C3N4 is of great importance. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide a V-NiS2 microsphere-attached porous g-C3N4 composite photocatalyst with simple and controllable preparation conditions and low production cost, as well as its preparation method, thereby producing a V-NiS2 microsphere-attached porous g-C3N4 composite photocatalyst with stable structure and high hydrogen production efficiency.

[0004] To achieve the above objectives, the present invention employs the following technical solution:

[0005] A method for preparing a V-NiS2 microsphere-attached porous g-C3N4 composite photocatalyst includes the following steps:

[0006] Step 1: Preparation of porous g-C3N4 nanosheets;

[0007] Step 2: Mix nickel acetate, ammonium metavanadate, thiourea, and hexamethyltetraammonium in a molar ratio of (1-4):(0.5-3):(1-8):(1-5) to obtain a mixed powder. Take 0.8-2.2g of the mixed powder and add 60mL of deionized water. First, sonicate for 45-125min. Then, add 0.005-0.02g of polypyrrole and 1-3g of the porous g-C3N4 nanosheets prepared in Step 1. Stir thoroughly and then quickly pour the mixture into the lining of a 100mL reaction vessel.

[0008] Step 3: After sealing the reaction vessel, place it in an oven and keep it at 140-200℃ for 12-24 hours. After the temperature in the oven drops to room temperature, remove the reaction vessel and cool it. Then centrifuge, wash the reagent, dry it, and finally mortar it to obtain the V-NiS2 / g-C3N4 photocatalyst.

[0009] The present invention also has the following technical features:

[0010] Preferably, the method for preparing the porous g-C3N4 nanosheets in step one includes:

[0011] S1. Place 10-15g of urea into a white porcelain boat, place it in a muffle furnace, and under the protection of inert gas, heat it to 450-650℃ at a heating rate of 4-10℃ / min, and hold it at that temperature for 3-6 hours for one calcination.

[0012] S2. After the sample cools down to room temperature in the furnace, it is then calcined a second time. The heating rate is 2-8℃ / min, the calcination temperature is 150-400℃, and the holding time is 1-4h.

[0013] S3. After secondary calcination, the sample was naturally cooled in the furnace and ground to obtain yellow powder, namely porous g-C3N4 nanosheets.

[0014] Furthermore, the grinding described in S3 refers to grinding in a mortar for 30 to 90 minutes.

[0015] Preferably, the thorough stirring in step two involves stirring on a magnetic stirrer for 120–720 minutes.

[0016] Preferably, the detergent used in step three is a wash made by washing with deionized water and anhydrous ethanol 3 to 5 times respectively.

[0017] Preferably, the drying process in step three involves placing the item in a vacuum drying oven at 80°C for 8–26 hours.

[0018] This invention also protects a V-NiS2 microsphere-attached porous g-C3N4 composite photocatalyst prepared by the method described above, wherein the V-NiS2 has a microsphere-shaped structure composed of nanosheets and its surface is uniformly attached with porous g-C3N4.

[0019] Compared with the prior art, the present invention has the following technical effects:

[0020] This invention employs a one-step hydrothermal method, first mixing a nickel source, a vanadium source, and carbon nitride, then performing a one-step hydrothermal process to obtain a composite photocatalytic material. The preparation conditions are simple and easily controlled, resulting in low production costs and facilitating industrial-scale production. The g-C3N4 preparation method transforms g-C3N4 into nanosheets with a porous structure. This structure enhances the exposure of active sites on the g-C3N4 photocatalyst, increases surface reaction efficiency, and effectively promotes the separation and transport of photogenerated charges, thereby improving efficiency. The same preparation method transforms V-NiS2 into a micron-sized spherical structure composed of nanosheets. This structure enhances the visible light absorption capacity of the V-NiS2 / g-C3N4 composite photocatalyst, effectively promotes the separation of photogenerated charges, increases its specific surface area and active sites during photocatalytic hydrogen production, thereby effectively improving hydrogen production efficiency.

[0021] The method for preparing V-NiS2 / g-C3N4 proposed in this invention incorporates carbon nitride during the synthesis of V-NiS2, promoting effective bonding between the two and enhancing the stability of their heterojunction. This accelerates the efficient transfer of photogenerated charges between materials, thereby achieving efficient hydrogen production. Furthermore, it employs only a hydrothermal method, resulting in a lower synthesis temperature that does not damage the original morphology and structure of the g-C3N4 sample. Attached Figure Description

[0022] Figure 1 The X-ray diffraction pattern of V-NiS2 / g-C3N4 prepared in Example 1 of this invention;

[0023] Figure 2 This is a scan image of V-NiS2 / g-C3N4 prepared in Example 1 of this study;

[0024] Figure 3 The image shows the performance of V-NiS2 / g-C3N4 prepared in Example 1. Detailed Implementation

[0025] The specific content of the present invention will be further explained in detail below with reference to the embodiments.

[0026] Example 1:

[0027] Step 1: Prepare porous sheet-like g-C3N4;

[0028] First, 12g of cyanamide was placed in a white porcelain boat and placed in a muffle furnace. Under inert gas protection, the calcination temperature was 500℃, the holding time was 2h, and the heating rate was 5℃ / min. After calcination, the sample was allowed to cool to room temperature with the furnace, and then it was calcined a second time at 150℃ for 4h with a heating rate of 5℃ / min. After the reaction was completed, a yellow blocky substance A was obtained. Then, it was taken out and placed in a mortar and ground for 35min until there was no obvious particle feel. It was collected for later use, thus obtaining porous sheet-like g-C3N4.

[0029] Step 2: Mix nickel acetate tetrahydrate, ammonium metavanadate, thiourea, and hexamethyltetraammonium in a molar ratio of 2:1.5:1.5:2 to obtain mixed powder B. Take 1.2g of the mixed powder and add 60mL of deionized water. First, sonicate for 65min. Then, add 0.01g of polypyrrole and 1.5g of yellow powder A in sequence. Then, stir on a magnetic stirrer for 160min. Then, quickly pour the mixture into the lining of a 100mL reaction vessel.

[0030] Step 3: Set the working temperature of the vacuum drying oven to 160℃. After the temperature inside the drying oven reaches the set temperature, place the sealed reaction vessel into the oven and keep it at that temperature for 17 hours. After the temperature inside the oven drops to room temperature, remove the reaction vessel and cool it. Pour out the cooled reaction solution and centrifuge it. Wash it three times with deionized water and anhydrous ethanol respectively to obtain a precipitate. Then place it in the vacuum drying oven at 80℃ for 16 hours to obtain solid C. Take it out and grind it for 40 minutes to obtain the V-NiS2 / g-C3N4 photocatalyst.

[0031] The photocatalytic effect of V-NiS2 / g-C3N4 was tested using a LabSolar 6A instrument. The specific test procedure included weighing 50 mg of the composite photocatalyst and 10 mL of isopropanol, placing them sequentially into a glass reaction vessel, adding water to make a 100 mL solution, and irradiating with light for 4 hours.

[0032] Figure 1 The image shows the X-ray diffraction pattern of V-NiS2 / g-C3N4 prepared in Example 1. The horizontal axis represents the 2θ angle, and the vertical axis represents the diffraction peak intensity. The peaks at 13° and 27° correspond to the (100) and (002) crystal planes of g-C3N4, respectively. V-NiS2 / g-C3N4 can also accurately correspond to g-C3N4 PDF#87-1526 and NiS2 PDF#89-1945, indicating that the V-NiS2 / g-C3N4 photocatalyst was successfully prepared.

[0033] Figure 2 The scan image of V-NiS2 / g-C3N4 prepared in Example 1 is shown below. Figure 2As shown, V-NiS2 exhibits a micron-sized spherical structure assembled from nanosheets, while g-C3N4 mainly consists of porous nanosheets attached to the surface of the micron-sized spheres.

[0034] Figure 3 The performance diagram of V-NiS2 / g-C3N4 prepared in Example 1 is shown below. Figure 3 As shown, V-NiS2 / g-C3N4 exhibits good hydrogen evolution performance, with a total hydrogen production of 3911 μmol in 4 hours.

[0035] Example 2:

[0036] Step 1: Prepare porous sheet-like g-C3N4;

[0037] First, 10g of cyanamide was placed in a white porcelain boat and placed in a muffle furnace. Under inert gas protection, the calcination temperature was 450℃, the holding time was 3.5h, and the heating rate was 6℃ / min. After calcination, the sample was allowed to cool to room temperature with the furnace, and then it was calcined a second time at 200℃ for 3h with a heating rate of 4℃ / min. After the reaction was completed, a yellow blocky substance A was obtained. It was then taken out and placed in a mortar and ground for 40min until there was no obvious particle feel. It was collected for later use, thus obtaining porous sheet-like g-C3N4.

[0038] Step 2: Mix nickel acetate tetrahydrate, ammonium metavanadate, thiourea, and hexamethyltetraammonium in a molar ratio of 2:1.5:5:3 to obtain mixed powder B. Take 0.8g of the mixed powder and add 60mL of deionized water. First, sonicate for 120min. Then, add 0.008g of polypyrrole and 1g of yellow powder A in sequence. Then, stir on a magnetic stirrer for 240min. Then, quickly pour the mixture into the 100mL reactor liner.

[0039] Step 3: Set the working temperature of the vacuum drying oven to 200℃. After the temperature inside the drying oven reaches the set temperature, place the sealed reaction vessel into the oven and keep it warm for 12 hours. After the temperature inside the oven drops to room temperature, remove the reaction vessel and cool it. Pour out the cooled reaction solution and centrifuge it. Wash it four times with deionized water and anhydrous ethanol respectively to obtain a precipitate. Then put it into the vacuum drying oven at 80℃ for 16 hours to obtain solid C. Take it out and grind it for 40 minutes to obtain the V-NiS2 / g-C3N4 photocatalyst.

[0040] The photocatalytic effect of V-NiS2 / g-C3N4 was tested using a LabSolar 6A instrument. The specific test procedure included weighing 60 mg of photocatalyst and 10 mL of isopropanol, and then placing them into a glass reaction vessel containing 90 mL of ultrapure water, followed by irradiation for 4 hours.

[0041] Example 3:

[0042] Step 1: Prepare porous sheet-like g-C3N4;

[0043] First, 14g of cyanamide was placed in a white porcelain boat and placed in a muffle furnace. Under inert gas protection, the calcination temperature was 550℃, the holding time was 3h, and the heating rate was 4℃ / min. After calcination, the sample was allowed to cool to room temperature with the furnace, and then it was calcined a second time at 300℃ for 2h with a heating rate of 5℃ / min. After the reaction was completed, a yellow blocky substance A was obtained. Then, it was taken out and placed in a mortar and ground for 40min until there was no obvious particle feel. It was collected for later use, thus obtaining porous sheet-like g-C3N4.

[0044] Step 2: Mix nickel acetate tetrahydrate, ammonium metavanadate, thiourea, and hexamethyltetraammonium in a molar ratio of 3:1.2:6:4 to obtain mixed powder B. Take 2.2g of the mixed powder and add 60mL of deionized water. First, sonicate for 105min. Then, add 0.015g of polypyrrole and 2.5g of yellow powder A in sequence. Then, stir on a magnetic stirrer for 120min. Finally, quickly pour the mixture into the 100mL reactor liner.

[0045] Step 3: Set the working temperature of the vacuum drying oven to 150℃. After the temperature inside the drying oven reaches the set temperature, place the sealed reaction vessel into the oven and keep it warm for 20 hours. After the temperature inside the oven drops to room temperature, remove the reaction vessel and cool it. Pour out the cooled reaction solution and centrifuge it. Wash it five times with deionized water and anhydrous ethanol respectively to obtain a precipitate. Then put it into the vacuum drying oven and dry it for 26 hours to obtain solid C. Take it out and grind it for 80 minutes to obtain V-NiS2 / g-C3N4 photocatalyst.

[0046] The photocatalytic effect of V-NiS2 / g-C3N4 was tested using a LabSolar 6A instrument. The specific test procedure included weighing 55 mg of photocatalyst and 15 mL of isopropanol, and then placing them into a glass reaction vessel containing 85 mL of ultrapure water, followed by irradiation for 4 hours.

[0047] Example 4:

[0048] Step 1: Prepare porous sheet-like g-C3N4;

[0049] First, 15g of cyanamide was placed in a white porcelain boat and placed in a muffle furnace. Under inert gas protection, the calcination temperature was 650℃, the holding time was 6h, and the heating rate was 10℃ / min. After calcination, the sample was allowed to cool to room temperature with the furnace, and then it was calcined a second time at 400℃ for 1h with a heating rate of 8℃ / min. After the reaction was completed, a yellow blocky substance A was obtained. It was then taken out, placed in a mortar, and ground for 90min until there was no obvious particle feel. It was collected for later use, thus obtaining porous sheet-like g-C3N4.

[0050] Step 2: Mix nickel acetate tetrahydrate, ammonium metavanadate, thiourea, and hexamethyltetraammonium in a molar ratio of 1:3:8:5 to obtain mixed powder B. Take 0.22g of the mixed powder and add 60mL of deionized water. First, sonicate for 45min. Then, add 0.005g of polypyrrole and 3g of yellow powder A in sequence. Then, stir on a magnetic stirrer for 360min. Then, quickly pour the mixture into the 100mL reactor liner.

[0051] Step 3: Set the working temperature of the vacuum drying oven to 140℃. After the temperature inside the drying oven reaches the set temperature, place the sealed reaction vessel into the oven and keep it warm for 22 hours. After the temperature inside the oven drops to room temperature, remove the reaction vessel and cool it. Pour out the cooled reaction solution and centrifuge it. Wash it 5 times with deionized water and anhydrous ethanol respectively to obtain a precipitate. Then put it into the vacuum drying oven and dry it for 8 hours to obtain solid C. Take it out and grind it for 80 minutes to obtain V-NiS2 / g-C3N4 photocatalyst.

[0052] The photocatalytic effect of V-NiS2 / g-C3N4 was tested using a LabSolar 6A instrument. The specific test procedure included weighing 55 mg of photocatalyst and 15 mL of isopropanol, and then placing them into a glass reaction vessel containing 85 mL of ultrapure water, followed by irradiation for 4 hours.

[0053] Example 5:

[0054] Step 1: Prepare porous sheet-like g-C3N4;

[0055] First, 12g of cyanamide was placed in a white porcelain boat and placed in a muffle furnace. Under inert gas protection, the calcination temperature was 600℃, the holding time was 5h, and the heating rate was 8℃ / min. After calcination, the sample was allowed to cool to room temperature with the furnace, and then it was calcined a second time at 300℃ for 32h with a heating rate of 2℃ / min. After the reaction was completed, a yellow blocky substance A was obtained. It was then taken out, placed in a mortar, and ground for 30min until there was no obvious particle feel. It was collected for later use, thus obtaining porous sheet-like g-C3N4.

[0056] Step 2: Mix nickel acetate tetrahydrate, ammonium metavanadate, thiourea and hexamethyltetraammonium in a molar ratio of 4:0.5:1:1 to obtain mixed powder B. Take 1.8g of mixed powder and add 60mL of deionized water. First, sonicate for 125min. Then, add 0.02g of polypyrrole and 2g of yellow powder A in sequence. Then, stir on a magnetic stirrer for 720min. Then, quickly pour the mixture into the 100mL reaction vessel liner.

[0057] Step 3: Set the working temperature of the vacuum drying oven to 180℃. After the temperature inside the drying oven reaches the set temperature, place the sealed reaction vessel into the oven and keep it warm for 24 hours. After the temperature inside the oven drops to room temperature, remove the reaction vessel and cool it. Pour out the cooled reaction solution and centrifuge it. Wash it 5 times with deionized water and anhydrous ethanol respectively to obtain a precipitate. Then put it into the vacuum drying oven and dry it for 20 hours to obtain solid C. Take it out and grind it for 80 minutes to obtain V-NiS2 / g-C3N4 photocatalyst.

[0058] The photocatalytic effect of V-NiS2 / g-C3N4 was tested using a LabSolar 6A instrument. The specific test procedure included weighing 55 mg of photocatalyst and 15 mL of isopropanol, and then placing them into a glass reaction vessel containing 85 mL of ultrapure water, followed by irradiation for 4 hours.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of the claims.

Claims

1. A method for preparing a V-NiS 2 microsphere attached porous g-C 3 N 4 composite photocatalyst, characterized in that, Includes the following steps: Step 1: Preparation of porous g-C3N4 nanosheets; Step 2: Mix nickel acetate, ammonium metavanadate, thiourea and hexamethyltetraammonium in a molar ratio of (1~4):(0.5~3):(1~8):(1~5) to obtain a mixed powder. Take 0.8~2.2 g of the mixed powder and add 60 mL of deionized water. First, sonicate for 45~125 min. Then, add 0.005~0.02 g of polypyrrole and 1~3 g of the porous g-C3N4 nanosheets prepared in Step 1. Stir thoroughly and then quickly pour the mixture into the lining of a 100 mL reaction vessel. Step 3: After sealing the reaction vessel, place it in an oven and keep it at 140~200 °C for 12~24 h. After the temperature in the oven drops to room temperature, take out the reaction vessel and cool it. Then centrifuge, wash the agent, dry it, and grind it to obtain V-NiS2 / g-C3N4 photocatalyst. The method for preparing porous g-C3N4 nanosheets described in step one includes: S1. Place 10-15 g of urea in a white porcelain boat, place it in a muffle furnace, and under the protection of inert gas, heat it to 450-650 °C at a heating rate of 4-10 °C / min, and hold it at that temperature for 3-6 h for one calcination. S2. After the sample cools down to room temperature in the furnace, it is then calcined a second time. The heating rate is 2~8 °C / min, the calcination temperature is 150~400 °C, and the holding time is 1~4 h. S3. After secondary calcination, the sample was naturally cooled in the furnace and ground to obtain yellow powder, namely porous g-C3N4 nanosheets.

2. The preparation method of the V-NiS2 microsphere-attached porous g-C3N4 composite photocatalyst as described in claim 1, characterized in that, The grinding described in S3 refers to grinding in a mortar for 30 to 90 minutes.

3. The preparation method of the V-NiS2 microsphere-attached porous g-C3N4 composite photocatalyst as described in claim 1, characterized in that, The thorough stirring mentioned in step two refers to stirring on a magnetic stirrer for 120~720 minutes.

4. The method for preparing V-NiS2 microspheres attached with holey g-C3N4 composite photocatalysts according to claim 1, characterized in that, The detergent mentioned in step three involves washing with deionized water and anhydrous ethanol 3 to 5 times respectively.

5. The method for preparing V-NiS2 microspheres attached with holey g-C3N4 composite photocatalysts according to claim 1, characterized in that, The drying process described in step three involves placing the item in a vacuum drying oven at 80°C for 8-26 hours.

6. The V-NiS2 microspheres attached hole-like g-C3N4 composite photocatalyst prepared by the method of any one of claims 1 to 5, characterized in that, V-NiS2 has a micron-sized spherical structure composed of nanosheets, and its surface is uniformly coated with porous g-C3N4.

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