Preparation method of sea urchin-like nonmetal hierarchical composite material
By synthesizing the composite photocatalytic material of graded porous carbon @Bi12O17Cl2 nanotubes, the lack of performance of traditional Bi12O17Cl2 materials in photocatalytic CO2 reduction was solved, and the effect of significantly improving CO2 reduction performance was achieved.
Patent Information
- Application Number
- CN202311449220.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-11-02
- Publication Date
- 2025-05-06
AI Technical Summary
Traditional Bi12O17Cl2 materials have problems with narrow photoresponse range, insufficient CO2 adsorption capacity and low photogenerated electron utilization in photocatalytic CO2 reduction. The existing modification method is single, resulting in limited performance improvement.
The composite photocatalytic material of graded porous carbon @Bi12O17Cl2 nanotubes is synthesized through calcining method, oil bath method and hydrothermal method to improve the charge separation efficiency and CO2 activation ability, thereby promoting the generation of CO during photocatalytic CO2 reduction.
This composite material significantly improves the CO generation rate during photocatalytic CO2 reduction, which is 2.90 times that of Bi12O17Cl2 monomer material, which proves that the introduction of graded porous carbon significantly improves the photocatalytic performance of the composite material.
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Figure CN119926434A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of catalyst preparation, and in particular relates to a method for preparing a non-metallic hierarchical composite material having a sea urchin-like shape. Background Art
[0002] The Industrial Revolution has brought two consequences to human society. On the one hand, the rapid development of industry has directly promoted the rapid development of science and technology and the continuous progress of society. On the other hand, the development of industry has caused excessive consumption of fossil energy and a sharp deterioration of the environment. Energy crisis and environmental pollution have sounded the alarm for mankind. In order to ensure the sustainable development of human society, scientists are committed to developing various environmentally friendly and efficient technologies to solve the survival status of human society. As an environmentally friendly emerging technology, semiconductor photocatalysis technology has shown immeasurable application prospects in energy conversion and environmental governance.
[0003] Bi 12 O 17 As a member of the BiOX family, Cl2 semiconductor materials not only have a suitable band gap, strong light absorption ability and highly controllable morphology, but also have a relatively positive conduction band position, and have attracted much attention in the field of photocatalytic CO2 reduction. 12 O 17 Cl2 materials also have problems such as narrow light response range, insufficient CO2 adsorption capacity and low utilization rate of photogenerated electrons. Although researchers have used various methods to improve its photocatalytic CO2 conversion efficiency, the modification methods used are single, so the performance improvement is very limited. Studies have found that ZIF-derived porous carbon materials have the advantages of large specific surface area, high CO2 adsorption capacity, good conductivity, and strong light reflection ability. 12 O 17 Composite Cl2 semiconductor materials would be an ideal method to enhance the photocatalytic CO2 reduction performance. Summary of the invention
[0004] The present invention aims to provide a hierarchical porous carbon@Bi with high efficiency photocatalytic CO2 reduction activity 12 O 17 Cl2 nanotube composite photocatalytic material and its preparation method. 12 O 17 Compared with Cl2 nanotubes, hierarchical porous carbon@Bi 12 O 17 The Cl2 nanotube composite photocatalytic material not only has a higher charge separation efficiency, but also has an enhanced CO2 activation ability, thereby promoting the production of CO during the photocatalytic CO2 reduction process. The catalyst is synthesized step by step through calcination, oil bath and hydrothermal methods, with mild reaction conditions and simple operation.
[0005] The technical solution of the present invention:
[0006] A hierarchical porous carbon@Bi 12 O 17 The preparation method of Cl2 nanotube composite photocatalytic material comprises the following steps:
[0007] (1) Cobalt nitrate hexahydrate and 2-methylimidazole were taken separately, added to a methanol solution to prepare solution A and solution B, solution B was added dropwise to solution A, and stirring was continued at room temperature for 12-48 hours, and then washed and dried to obtain a ZIF-67 precursor;
[0008] (2) calcining the ZIF-67 precursor to obtain a hierarchical porous carbon material;
[0009] (3) treating the graded porous carbon material with acetic acid, washing it to neutrality, and drying it;
[0010] (4) taking bismuth nitrate pentahydrate and polyvinyl pyrrolidone, and then adding them to a mannitol aqueous solution to prepare solution C; taking sodium chloride and adding it to a mannitol aqueous solution to prepare solution D;
[0011] (5) adding solution D obtained in step (4) dropwise to solution C, stirring rapidly, then adding sodium hydroxide solution to adjust the pH of the reaction solution, continuing stirring at room temperature, then pouring the mixed solution into a 25 mL polytetrafluoroethylene-lined autoclave, and heating for reaction;
[0012] (6) The product obtained in step (5) is centrifuged, washed, and dried to obtain Bi 12 O 17 Cl2 nanotube photocatalytic materials;
[0013] (7) The dried Bi 12 O 17 Cl2 nanotubes and acid-treated hierarchical porous carbon materials were added to a round-bottom flask and placed in an oil bath at 50-120°C for 2-6 hours. After centrifugation, washing, and drying, hierarchical porous carbon@Bi was obtained. 12 O 17 Cl2 nanotube composite photocatalytic materials.
[0014] Optionally, the amount of cobalt nitrate in the solution A of step (1) is 1-6 mmol, the amount of 2-methylimidazole in the solution B of step (1) is 2-12 mmol, and the amount of methanol solution is 20-120 mL.
[0015] Optionally, the calcination temperature in step (2) is 200-600° C., and the calcination time is 2-12 h. Optionally, the calcination condition in step (2) is calcination in an inert atmosphere.
[0016] Optionally, in the acid treatment process of step (3), the amount of acetic acid used is 10-40 mL, the amount of ethanol used is 10-40 mL, and the amount of porous carbon used is 20-80 mg.
[0017] Optionally, the oil bath temperature during the acid treatment in step (3) is 40-100°C.
[0018] Optionally, in the solution C of step (4), the amount of bismuth nitrate is 0.2-1 mmol, the amount of polyvinyl pyrrolidone is 0.1-0.5 g, and the concentration of the mannitol aqueous solution is 0.05-0.2 mol / L.
[0019] Optionally, in the solution D of step (4), the amount of sodium chloride used is 0.3-0.9 mmol.
[0020] Optionally, the pH of the solution in step (5) is 10-14.
[0021] Optionally, the stirring time at room temperature in step (5) is 10-60 min.
[0022] Optionally, in step (7), Bi 12 O 17 The amount of Cl2 used is 50-200 mg, and the proportion of the graded porous carbon material is 0.1-6 wt%.
[0023] Optionally, in step (7), the oil bath temperature is 50-120° C., and the reaction time is 2-6 h.
[0024] Optionally, the drying temperature in step (7) is 45° C. and the drying time is 2-12 h.
[0025] The present invention obtains a hierarchical porous carbon @Bi 12 O 17 The Cl2 nanotube composite photocatalytic material is obtained by a step-by-step synthesis method.
[0026] The hierarchical porous carbon@Bi obtained by the present invention 12 O 17 Cl2 nanotube composite photocatalytic material is used for photocatalytic CO2 reduction to produce CO. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1 for Bi 12 O 17 Cl2 monomer materials and hierarchical porous carbon@Bi 12 O 17 XRD patterns of Cl2 composites.
[0028] Figure 2 for Bi12 O 17 Cl2 monomer materials and hierarchical porous carbon@Bi 12 O 17 TEM image of Cl2 composite material.
[0029] Figure 3 for Bi 12 O 17 Cl2 monomer materials and hierarchical porous carbon@Bi 12 O 17 CO release rate curve during photocatalytic CO2 reduction of Cl2 composite material. DETAILED DESCRIPTION
[0030] In this embodiment, the molar ratio of bismuth nitrate to sodium chloride is 1:1, and when the pH is adjusted to 10-14, it is conducive to the formation of Bi 12 O 17 Cl2 nanotubes, beyond this pH range, some nanosheets or other bismuth-rich BiOCl materials will appear. Therefore, in this embodiment, by reasonably adjusting the pH of the reaction solution, Bi 12 O 17 Cl2 nanotubes. In this embodiment, nitrogen is used as a protective gas during the calcination of the ZIF-67 precursor to avoid its oxidation, and calcination at 200-600°C for 2-6h is conducive to the formation of a porous structure, otherwise it will lead to the collapse and destruction of the carbon structure. Therefore, in this embodiment, by controlling the temperature and time of the ZIF-67 precursor calcination process, an ideal hollow hierarchical porous carbon material can be obtained. In addition, the hierarchical porous carbon@Bi 12 O 17 The proportion of porous carbon material in the Cl2 composite photocatalytic material ranges from 0.1 to 6wt%. On the one hand, if the graded porous carbon material is added too much, it will cover a part of the porous carbon pore structure, which will not only hinder the composite material from absorbing and utilizing light, but also reduce the reaction active sites, thereby affecting the photocatalytic performance of the composite photocatalytic material. On the other hand, if the graded porous carbon material is added too little, the composite material will not be able to effectively improve the charge separation efficiency, and will not be conducive to the activation of CO2. Therefore, within the incorporation range of the graded porous carbon material, the composite photocatalytic material has better photocatalytic performance.
[0031] Example 1
[0032] Cobalt nitrate hexahydrate is used as a cobalt source and 2-methylimidazole is used as a ligand. Solution A and solution B are prepared in 40 mL of methanol solution respectively, wherein the amount of cobalt nitrate is 1-4 mmol, and the amount of 2-methylimidazole is 2-6 mmol. When solution A is stirred, solution B is added dropwise to solution A and stirred rapidly, and then stirred at room temperature for 12-24 hours. After centrifugation, washing and drying, a ZIF-67 precursor is obtained. The ZIF-67 precursor is calcined in an inert atmosphere at a calcination temperature of 200-400°C for a calcination time of 2-6 hours to obtain a hierarchical porous carbon material. Bismuth nitrate pentahydrate is used as a bismuth source and polyvinyl pyrrolidone is used as a template directing agent. Solution C is prepared in 15 mL of mannitol solution, wherein the amount of bismuth nitrate is 0.2-0.4 mmol, the amount of polyvinyl pyrrolidone is 0.1-0.5 g, and the concentration of the mannitol aqueous solution is 0.05-0.1 mol / L; in another container, sodium chloride is used as a chlorine source and solution D is prepared in 4 mL of mannitol aqueous solution, wherein the amount of sodium chloride is 0.3-0.6 mmol. C is under stirring conditions, solution D is added dropwise to solution C, and stirred rapidly, then sodium hydroxide solution is added to adjust the pH of the reaction solution to 10-12, and stirring is continued at room temperature for 10-40 minutes, and the above solution is poured into a 25mL polytetrafluoroethylene-lined autoclave for heating reaction at a temperature of 120-150°C for 2-5 hours, the obtained product is centrifuged, and then washed several times with deionized water and anhydrous ethanol, respectively, and dried at 45°C for 2-6 hours. 12 O 17 Cl2 nanotubes and acid-treated hierarchical porous carbon materials were added to a round-bottom flask and placed in an oil bath at 50-90°C for 2-4 hours. After centrifugation, washing, and drying, hierarchical porous carbon@Bi was obtained. 12 O 17 Cl2 nanotube composite photocatalytic materials.
[0033] Example 2
[0034] Cobalt nitrate hexahydrate is used as a cobalt source and 2-methylimidazole is used as a ligand. Solution A and solution B are prepared in 30 mL of methanol solution, respectively. The amount of cobalt nitrate is 4 mmol, and the amount of 2-methylimidazole is 4 mmol. While solution A is stirring, solution B is added dropwise to solution A and stirred rapidly. Then stirring is continued at room temperature for 36 hours. After centrifugation, washing and drying, a ZIF-67 precursor is obtained. The ZIF-67 precursor is calcined in an inert atmosphere at a calcination temperature of 400°C and a calcination time of 6 hours to obtain a hierarchical porous carbon material. Bismuth nitrate pentahydrate was used as the bismuth source and polyvinyl pyrrolidone was used as the template directing agent. Solution C was prepared in 15 mL of mannitol solution, wherein the amount of bismuth nitrate was 0.5 mmol, the amount of polyvinyl pyrrolidone was 0.2 g, and the concentration of the mannitol aqueous solution was 0.1 mol / L; in another container, sodium chloride was used as the chlorine source, and solution D was prepared in 4 mL of mannitol aqueous solution, wherein the amount of sodium chloride was 0.5 mmol. When solution C was stirred, solution D was added dropwise to solution C and stirred rapidly, and then sodium hydroxide solution was added to adjust the pH of the reaction solution to 12, and stirring was continued at room temperature for 20 minutes. The above solution was poured into a 25 mL polytetrafluoroethylene-lined autoclave and heated for reaction at a reaction temperature of 150 ° C and a reaction time of 3 hours. The obtained product was centrifuged, washed several times with deionized water and anhydrous ethanol respectively, and dried at 45 ° C for 6 hours. The dried Bi 12 O 17 Cl2 nanotubes and acid-treated hierarchical porous carbon materials were added to a round-bottom flask and placed in an oil bath at 60°C for 4 h. After centrifugation, washing, and drying, hierarchical porous carbon@Bi was obtained. 12 O 17 Cl2 nanotube composite photocatalytic materials.
[0035] Example 3
[0036] Cobalt nitrate hexahydrate is used as a cobalt source and 2-methylimidazole is used as a ligand. Solution A and solution B are prepared in 30 mL of methanol solution, respectively. The amount of cobalt nitrate is 2 mmol, and the amount of 2-methylimidazole is 2 mmol. While solution A is stirring, solution B is added dropwise to solution A and stirred rapidly. The stirring is then continued at room temperature for 24 hours. A ZIF-67 precursor is obtained after centrifugation, washing, and drying. The ZIF-67 precursor is calcined in an inert atmosphere at a calcination temperature of 500°C for 6 hours to obtain a hierarchical porous carbon material. Bismuth nitrate pentahydrate was used as the bismuth source and polyvinyl pyrrolidone was used as the template directing agent. Solution C was prepared in 15 mL of mannitol solution, wherein the amount of bismuth nitrate was 0.5 mmol, the amount of polyvinyl pyrrolidone was 0.1 g, and the concentration of the mannitol aqueous solution was 0.1 mol / L. In another container, sodium chloride was used as the chlorine source and solution D was prepared in 4 mL of mannitol aqueous solution, wherein the amount of sodium chloride was 0.5 mmol. While solution C was under stirring conditions, solution D was added dropwise to solution C and stirred rapidly. Then sodium hydroxide solution was added to adjust the pH of the reaction solution to 13. Stirring was continued at room temperature for 10 min. The above solution was poured into a 25 mL polytetrafluoroethylene-lined autoclave and heated for reaction at 160 ° C for 3 h. The obtained product was centrifuged, washed several times with deionized water and anhydrous ethanol, respectively, and dried at 45 ° C for 8 h. The dried Bi 12 O 17 Cl2 nanotubes and acid-treated hierarchical porous carbon materials were added to a round-bottom flask and placed in an oil bath at 80 °C for 6 h. After centrifugation, washing, and drying, hierarchical porous carbon@Bi was obtained. 12 O 17 Cl2 nanotube composite photocatalytic materials.
[0037] Example 4
[0038] Cobalt nitrate hexahydrate is used as a cobalt source and 2-methylimidazole is used as a ligand. Solution A and solution B are prepared in 30 mL of methanol solution, respectively. The amount of cobalt nitrate is 2 mmol and the amount of 2-methylimidazole is 8 mmol. While solution A is stirring, solution B is added dropwise to solution A and stirred rapidly. The stirring is then continued at room temperature for 24 hours. A ZIF-67 precursor is obtained after centrifugation, washing and drying. The ZIF-67 precursor is calcined in an inert atmosphere at a calcination temperature of 450°C for 6 hours to obtain a hierarchical porous carbon material. Bismuth nitrate pentahydrate was used as the bismuth source and polyvinyl pyrrolidone was used as the template directing agent. Solution C was prepared in 15 mL of mannitol solution, wherein the amount of bismuth nitrate was 0.5 mmol, the amount of polyvinyl pyrrolidone was 0.2 g, and the concentration of the mannitol aqueous solution was 0.1 mol / L; in another container, sodium chloride was used as the chlorine source, and solution D was prepared in 4 mL of mannitol aqueous solution, wherein the amount of sodium chloride was 0.5 mmol. When solution C was stirred, solution D was added dropwise to solution C and stirred rapidly, and then sodium hydroxide solution was added to adjust the pH of the reaction solution to 12.5, and stirring was continued at room temperature for 30 minutes. The above solution was poured into a 25 mL polytetrafluoroethylene-lined autoclave and heated to react at a reaction temperature of 150 ° C and a reaction time of 3 hours. The obtained product was centrifuged, washed several times with deionized water and anhydrous ethanol respectively, and dried at 45 ° C for 6 hours. The dried Bi 12 O 17 Cl2 nanotubes and acid-treated hierarchical porous carbon materials were added to a round-bottom flask and placed in an oil bath at 80°C for 3 h. After centrifugation, washing, and drying, hierarchical porous carbon@Bi was obtained. 12 O 17 Cl2 nanotube composite photocatalytic materials.
[0039] Comparative Example
[0040] Preparation of Bi 12 O 17 The steps of Cl2 nanotube photocatalyst are as follows: 0.5mmol bismuth nitrate pentahydrate and 0.2g polyvinyl pyrrolidone are added to 15mL 0.1mol / L mannitol solution to prepare solution A. In another container, 0.05mmol sodium chloride is added to 4mL mannitol solution to prepare solution B. While solution A is stirred, solution B is added dropwise to solution A and stirred rapidly. Then sodium hydroxide solution is added to adjust the pH of the reaction solution to 12.5. The stirring time at room temperature is 30min. The above solution is poured into a 25mL polytetrafluoroethylene-lined autoclave and heated to react at a reaction temperature of 150°C for 3h. The obtained product is centrifuged, washed several times with deionized water and anhydrous ethanol, and dried at 45°C for 6h.
[0041] Performance testing:
[0042] Figure 1 for Bi 12 O 17 Cl2 monomer materials and porous carbon@Bi 12 O 17 XRD patterns of the Cl2 composite materials, where Bi 12 O 17 Cl2 is Bi 12 O 17 Cl2 nanotubes, porous carbon@Bi 12 O 17 Cl2 is Bi 12 O 17 Composite materials of Cl2 nanotubes and hierarchical porous carbon, Figure 1 The spectrum corresponds to Bi 12 O 17 Cl2 JCPDS No.37-0702.
[0043] Figure 2 for Bi 12 O 17 Cl2 monomer material (a) and porous carbon@Bi 12 O 17 TEM images of Cl2 composites (b) and porous carbon@Bi 12 O 17 HR-TEM image of Cl2 composite material (c), where Bi 12 O 17 Cl2 is Bi 12 O 17 Cl2 nanotubes, the diameter of the nanotubes is 6nm, porous carbon@Bi 12 O 17 Cl2 is Bi 12 O 17 The composite material of Cl2 nanotubes and hierarchical porous carbon, HR-TEM images show that the nanotubes and hierarchical porous carbon materials form a close interface contact, where the (117) crystal plane corresponds to Bi 12 O 17 Cl2 nanotubes.
[0044] Figure 3 for Bi 12 O 17 Cl2 monomer materials and porous carbon@Bi 12 O 17 The CO release rate curve during the photocatalytic CO2 reduction process of Cl2 composite materials, where Bi 12 O 17 Cl2 is Bi 12 O 17 Cl2 nanotubes, porous carbon@Bi12 O 17 Cl2 is Bi 12 O 17 Composites of Cl2 nanotubes and hierarchical porous carbon, Bi 12 O 17 The rate of photocatalytic CO2 reduction to CO by Cl2 monomer within 5 h was 58.9 μmol g -1 , while porous carbon@Bi 12 O 17 The rate of CO2 reduction to CO generation by Cl2 composite photocatalytic material within 5 h was 170.8 μmol g -1 , for Bi 12 O 17 The introduction of hierarchical porous carbon improves the photocatalytic CO2 reduction performance of the composite material.
Claims
1. A method for preparing a non-metallic hierarchical composite material having a sea urchin-like shape, characterized in that: The following steps are involved: (1) Cobalt nitrate hexahydrate and 2-methylimidazole were taken separately, added to a methanol solution to prepare solution A and solution B, stirred evenly, and then solution B was added dropwise to solution A, and continued to stir at room temperature for 12-48 hours to obtain a ZIF-67 precursor; (2) calcining the ZIF-67 precursor to obtain a hierarchical porous carbon material; (3) treating the graded porous carbon material with acetic acid, washing and drying; (4) taking bismuth nitrate pentahydrate and polyvinyl pyrrolidone, and then adding them to a mannitol aqueous solution to prepare solution C; taking sodium chloride and adding it to a mannitol aqueous solution to prepare solution D; (5) adding solution D obtained in step (4) dropwise to solution C, stirring rapidly, then adding sodium hydroxide solution to adjust the pH of the reaction solution, continuing stirring at room temperature, then pouring the mixed solution into a polytetrafluoroethylene-lined autoclave, and heating for reaction; (6) The product obtained in step (5) is centrifuged, washed, and dried to obtain Bi 12 O 17 Cl2 nanotube photocatalytic materials. (7) The dried Bi 12 O 17 Cl2 nanotubes and acid-treated hierarchical porous carbon materials were added to a round-bottom flask and placed in an oil bath at 50-120°C for 2-6 hours. After centrifugation, washing, and drying, hierarchical porous carbon@Bi was obtained. 12 O 17 Cl2 nanotube composite photocatalytic materials. (7) The dried Bi 12 O 17 Cl2 nanotubes and acid-treated hierarchical porous carbon materials are uniformly dispersed in an ethanol aqueous solution with a volume ratio of 2-7:3-8, the reaction temperature is 40-90 ° C, the reaction time is 2-6h, and after centrifugation, washing and drying, hierarchical porous carbon@Bi is obtained. 12 O 17 Cl2 nanotube composite photocatalytic materials.
2. The method for preparing the non-metallic hierarchical composite material having a sea urchin-like shape according to claim 1, characterized in that: The amount of cobalt nitrate in the solution A of step (1) is 1-6 mmol, the amount of 2-methylimidazole in the solution B of step (1) is 2-12 mmol, and the amount of methanol solution is 20-120 mL.
3. The method for preparing the non-metallic hierarchical composite material having a sea urchin-like shape according to claim 1, characterized in that: The calcination conditions in step (2) are calcination at a temperature of 200-600° C. for 2-12 hours; the calcination conditions in step (2) are calcination in an inert atmosphere.
4. The method for preparing the non-metallic hierarchical composite material having a sea urchin-like shape according to claim 1, characterized in that: The amount of acetic acid used in the acid treatment process of step (3) is 10-40 mL. The amount of ethanol used is 10-40 mL, and the amount of porous carbon used is 20-80 mg. The temperature of the oil bath during the acid treatment in step (3) is 40-100°C.
5. The method for preparing the non-metallic hierarchical composite material having a sea urchin-like shape according to claim 1, characterized in that: In the solution C of step (4), the amount of bismuth nitrate is 0.2-1 mmol, the amount of polyvinyl pyrrolidone is 0.1-0.5 g, and the concentration of the mannitol aqueous solution is 0.05-0.2 mol / L. In the solution D of step (4), the amount of sodium chloride is 0.3-0.9 mmol.
6. The method for preparing the non-metallic hierarchical composite material having a sea urchin-like shape according to claim 1, characterized in that: The pH of the solution in step (5) is 10-14. The stirring time at room temperature in step (5) is 10-60 min.
7. The method for preparing the non-metallic hierarchical composite material having a sea urchin-like shape according to claim 1, characterized in that: In step (7), Bi 12 O 17 The amount of Cl2 used is 50-200 mg, the proportion of the graded porous carbon material is 0.1-6 wt %. The oil bath temperature in step (7) is 50-120° C., and the reaction time is 2-6 h. The drying temperature in step (7) is 45° C., and the drying time is 2-12 h.
8. A method for preparing a non-metallic hierarchical composite material having a sea urchin-like shape, characterized in that: It is prepared by the preparation method according to any one of claims 1 to 7, wherein Bi 12 O 17 Cl2 nanotubes were successfully composited with hierarchical porous carbon materials.
9. Use of the non-metallic hierarchical composite material having a sea urchin-like shape as claimed in claim 8 for photocatalytic CO2 reduction.