A composite material with stability and good photocatalytic performance, and a preparation method and application thereof
By combining Cs2TeBr6 microcrystals with g-C3N4 powder, a stable composite material (Cs2TeBr6/g-C3N4) with good photocatalytic performance was prepared, which solved the problems of toxicity and instability of lead halide perovskite, improved the photocatalytic reduction efficiency of CO2, and is suitable for large-scale production.
Patent Information
- Application Number
- CN202311017791.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-11
- Publication Date
- 2025-12-09
- Estimated Expiration
- 2043-08-11
AI Technical Summary
Existing lead halide perovskite photocatalysts suffer from lead toxicity and instability, limiting their widespread application. Furthermore, lead-free Cs2TeX6 microcrystals exhibit insufficient surface active sites and rapid electron-hole recombination rates during photocatalytic carbon dioxide reduction, affecting their performance.
Cs2TeBr6 microcrystals were combined with g-C3N4 powder to form a Cs2TeBr6/g-C3N4 composite material. The composite material was prepared by controlling the mass percentage of Cs2TeBr6 microcrystal powder to be between 1% and 9% and by using a simple mixing and grinding method.
A composite material with good stability and excellent photocatalytic performance has been achieved, which significantly improves the photocatalytic reduction effect of CO2, reduces preparation cost and energy consumption, and is suitable for large-scale production.
Smart Images
Figure CN117085720B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of preparation of composite materials, and relates to a composite material with stability and good photocatalytic performance and a preparation method and application thereof. BACKGROUND
[0002] The original metal halide refers to CaTiO3, which is an oxide of cubic crystal system and was discovered by a Russian scientist Perovskite, and is named after his surname. The metal halide is generally measured by the collodion silver chloride printing method, most of which is ABX3 type cubic space group and is in the form of cubic crystal. Later, substances similar to the crystal structure of the metal halide are collectively referred to as metal halide perovskite.
[0003] The increasing industrialization and consumption of fossil fuels have led to the well-known energy crisis and serious global warming. Photocatalytic carbon dioxide emission reduction provides a promising solution to simultaneously solve these problems. Although significant progress has been reported, it is still crucial to develop powerful, selective, inexpensive solar-driven carbon dioxide emission reduction photocatalysts. Halide lead perovskite has the advantages of large absorption coefficient, adjustable band gap, strong visible light capture ability, high carrier mobility and the like, and is considered as an ideal photocatalyst candidate material. In recent years, halide lead perovskite has been used for photocatalytic dye degradation, hydroxymethyl oxidation, hydrogen production, organic reactions and CO2 reduction and the like. However, the toxicity and long-term instability of lead undoubtedly hinder its wide application. Therefore, inorganic lead-free halide perovskite has become an indispensable research direction for the next step of developing new photoelectronic materials and devices.
[0004] Therefore, in order to improve the side effects of lead elements in the existing lead halide metal halide material, more and more scholars are interested in the research of lead-free metal halide nanomaterials in recent years. Among them, the stable lead-free Cs2TeX6(X=Cl, Cl 0.5 Br 0.5 ,Br,Br 0.5 I 0.5 , and I) perovskite microcrystals have been confirmed to be used for efficient CO2 photocatalytic reduction, wherein the prepared Cs2TeBr6 microcrystals have strong photocatalytic performance, and have the disadvantages of insufficient surface active sites and fast electron-hole recombination speed. g-C3N4 has the advantages of simple preparation, low cost and good physical and chemical properties.
[0005] Therefore, in order to obtain a catalyst with good stability and excellent catalytic performance, it is necessary to study the preparation method of the composite material Cs2TeBr6 / g-C3N4 obtained by compounding Cs2TeBr6 microcrystals and g-C3N4 and the corresponding performance. SUMMARY
[0006] Therefore, one of the purposes of the present application is to provide a composite material which is stable and has good photocatalytic performance; another purpose of the present application is to provide a preparation method of the composite material which is stable and has good photocatalytic performance; and a third purpose of the present application is to provide an application of the composite material which is stable and has good photocatalytic performance in photocatalytic reduction of CO2.
[0007] To achieve the above-mentioned purposes, the present application provides the following technical solutions.
[0008] 1. A composite material which is stable and has good photocatalytic performance, the composite material (Cs2TeBr6 / g-C3N4) comprising Cs2TeBr6 microcrystalline powder and g-C3N4 powder, wherein the mass percentage of the Cs2TeBr6 microcrystalline powder in the composite material (Cs2TeBr6 / g-C3N4) is 1% to 9%.
[0009] Preferably, the Cs2TeBr6 microcrystalline powder is prepared by the following method:
[0010] (1) Cesium bromide and tellurium tetrabromide are added to a sealed container containing a hydrogen chloride solution and mixed uniformly;
[0011] (2) The sealed container in step (1) is placed in an oven and heated to 180℃, then kept at 180℃ for another 10h, and taken out after slowly cooling to room temperature within 24h;
[0012] (3) The solution taken out in step (2) is repeatedly washed with anhydrous ethanol, then centrifuged at a speed of 9000-10000rpm for 5-6min, the supernatant is removed to obtain a precipitate, and the precipitate is placed in a vacuum drying box and dried at 60-70℃ for 4-5h to obtain the Cs2TeBr6 microcrystalline powder.
[0013] Further preferably, the molar ratio of hydrogen chloride contained in the cesium bromide and tellurium tetrabromide solution is 2:1;
[0014] The molar volume ratio of the cesium bromide and hydrogen chloride solution is 2:5, mmol:mL.
[0015] Further preferably, the sealed container is a polytetrafluoroethylene autoclave.
[0016] Preferably, the g-C3N4 powder is prepared by the following method:
[0017] Melamine is placed in a tube furnace, heated to 600℃, and kept at 600℃ in an air-filled environment for 300min, and then naturally cooled to room temperature, and the obtained powder is g-C3N4 powder.
[0018] More preferably, the heating rate of the tubular furnace is 5°C / min.
[0019] 2. The above composite material can be prepared by mixing and grinding Cs2TeBr6 microcrystalline powder and g-C3N4 powder.
[0020] Preferably, the grinding time is 5 to 10 minutes.
[0021] 3. Application of the above composite materials in photocatalytic reduction of CO2.
[0022] The beneficial effects of this invention are as follows: This invention discloses a stable composite material (Cs2TeBr6 / g-C3N4) with good photocatalytic performance. This composite material (Cs2TeBr6 / g-C3N4) comprises Cs2TeBr6 microcrystalline powder and g-C3N4 powder, wherein the mass percentage of Cs2TeBr6 microcrystalline powder in the composite material (Cs2TeBr6 / g-C3N4) is 1% to 9%. This composite material (Cs2TeBr6 / g-C3N4) exhibits good photocatalytic performance and excellent stability, demonstrating great application potential in the field of photocatalysis. Furthermore, the preparation method of this composite material (Cs2TeBr6 / g-C3N4) is simple and easy to operate, requires low equipment standards, is low-cost, and low-energy-consumption, making it suitable for large-scale production.
[0023] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description
[0024] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:
[0025] Figure 1 The XRD patterns are of the Cs2TeBr6 microcrystalline powder, g-C3N4 powder, and stable composite material (1% Cs2TeBr6 / g-C3N4) with good photocatalytic performance prepared in Example 1.
[0026] Figure 2 SEM images of the Cs2TeBr6 microcrystalline powder (a), g-C3N4 powder (b), and stable composite material (1% Cs2TeBr6 / g-C3N4) (c) with good photocatalytic performance prepared in Example 1;
[0027] Figure 3TEM images of the stable and good photocatalytic performance composite material (Cs2TeBr6 / g-C3N4) prepared in Example 1;
[0028] Figure 4 SEM images of the stable and good photocatalytic performance composite material (Cs2TeBr6 / g-C3N4) prepared in Example 2 and Example 3. DETAILED DESCRIPTION
[0029] The present application will be described in detail with specific embodiments hereinafter, and those skilled in the art can easily understand other advantages and effects of the present application from the disclosure. The present application can also be implemented or applied by other different specific embodiments, and various modifications or changes can be made to the details in the specification based on different views and applications without departing from the spirit of the present application. It should be noted that the drawings provided in the following examples only illustrate the basic concept of the present application in a schematic manner, and the features in the following examples and embodiments can be combined with each other without conflict.
[0030] Example 1
[0031] A stable and good photocatalytic performance composite material (1% Cs2TeBr6 / g-C3N4), the specific preparation method comprises the following steps:
[0032] 1. Preparation of Cs2TeBr6 microcrystalline powder: (1) 2 mmol of cesium bromide (CsBr) and 1 mmol of tellurium tetrabromide (TeBr4) were added to a polytetrafluoroethylene autoclave containing 5 mL of a hydrogen chloride (HCl) solution (the molar volume concentration of HCl in the solution was 16.52 mmol / mL) and mixed uniformly; (2) the polytetrafluoroethylene autoclave with the mixture uniformly mixed in step (1) was placed in an oven. After heating to 180°C, it was kept at 180°C for another 10 h, and then slowly cooled to room temperature within 24 h and taken out; (3) the solution taken out after cooling in step (2) was centrifuged at a speed of 9000 rpm for 6 min, and after removing the supernatant, it was washed with anhydrous ethanol, and then the washed solution was centrifuged at a speed of 9000 rpm for 6 min, and after removing the supernatant, it was washed with anhydrous ethanol, and the centrifugation and washing were repeated 4 times to obtain a precipitate, which was placed in a vacuum drying box and dried at 70°C for 4 h to obtain Cs2TeBr6 microcrystalline powder.
[0033] 2. Preparation of g-C3N4 powder: 10 g of melamine was placed in a tube furnace, the temperature was raised to 600°C at a rate of 5°C / min, and kept at 600°C in an environment filled with air for 300 min, and then naturally cooled to room temperature, and the obtained powder was g-C3N4 powder.
[0034] 3. Preparation of the composite material (1% Cs2TeBr6 / g-C3N4): The Cs2TeBr6 microcrystalline powder and g-C3N4 powder prepared according to the method of Example 1 are mixed and ground for 5 min to obtain the composite material (1% Cs2TeBr6 / g-C3N4).
[0035] Example 2
[0036] The Cs2TeBr6 microcrystalline powder and g-C3N4 powder are prepared according to the method of Example 1, and then the prepared Cs2TeBr6 microcrystalline powder 0.005 g and g-C3N4 powder 0.095 g are mixed and ground for 5 min to obtain the composite material (5% Cs2TeBr6 / g-C3N4) which is stable and has good photocatalytic performance.
[0037] Example 3
[0038] The Cs2TeBr6 microcrystalline powder and g-C3N4 powder are prepared according to the method of Example 1, and then the prepared Cs2TeBr6 microcrystalline powder 0.009 g and g-C3N4 powder 0.091 g are mixed and ground for 5 min to obtain the composite material (9% Cs2TeBr6 / g-C3N4) which is stable and has good photocatalytic performance.
[0039] Example 4
[0040] A composite material (1% Cs2TeBr6 / g-C3N4) which is stable and has good photocatalytic performance, the specific preparation method comprising the following steps:
[0041] 1. Preparation of Cs2TeBr6 microcrystalline powder: (1) 2 mmol of cesium bromide (CsBr) and 1 mmol of tellurium tetrabromide (TeBr4) are added to 5 mL of a polytetrafluoroethylene autoclave containing a hydrogen chloride (HCl) solution (the molar volume concentration of HCl in the solution is 16.52 mmol / mL) and mixed uniformly; (2) the polytetrafluoroethylene autoclave with the mixture uniformly mixed in step (1) is placed in an oven and heated to 180°C, and then kept at 180°C for 10 h, and then slowly cooled to room temperature within 24 h and taken out; (3) the solution taken out after cooling in step (2) is centrifuged at a speed of 10000 rpm for 5 min, the supernatant is removed, and then washed with anhydrous ethanol, and then the washed solution is centrifuged at a speed of 10000 rpm for 5 min, the supernatant is removed, and then washed with anhydrous ethanol, and the centrifugation and washing are repeated 5 times to obtain a precipitate, which is placed in a vacuum drying box and dried at 70°C for 4 h to obtain the Cs2TeBr6 microcrystalline powder.
[0042] 2. Preparation of g-C3N4 powder: 10 g of melamine was placed in a tube furnace, the temperature was raised to 600 ℃ at a rate of 5 ℃ / min, and kept at 600 ℃ in an environment full of air for 300 min, and then naturally cooled to room temperature, and the obtained powder was g-C3N4 powder.
[0043] 3. Preparation of composite material (1% Cs2TeBr6 / g-C3N4): The above prepared Cs2TeBr6 microcrystalline powder 0.001 g and g-C3N4 powder 0.099 g were mixed and ground for 10 min.
[0044] Example 5
[0045] A composite material (1% Cs2TeBr6 / g-C3N4) which is stable and has good photocatalytic performance, and a specific preparation method comprises the following steps:
[0046] 1. Preparation of Cs2TeBr6 microcrystalline powder: (1) 2 mmol of cesium bromide (CsBr) and 1 mmol of tellurium tetrabromide (TeBr4) were added to a polytetrafluoroethylene autoclave containing 5 mL of a hydrogen chloride (HCl) solution (the molar volume concentration of HCl in the solution was 16.52 mmol / mL) and mixed uniformly; (2) the polytetrafluoroethylene autoclave mixed uniformly in step (1) was placed in an oven and heated to 180 ℃, and then kept at 180 ℃ for 10 h, and then slowly cooled to room temperature within 24 h and taken out; (3) the solution taken out after cooling in step (2) was centrifuged at a speed of 10000 rpm for 5 min, and after removing the supernatant, washed with anhydrous ethanol, and then the washed solution was centrifuged at a speed of 10000 rpm for 5 min, and after removing the supernatant, washed with anhydrous ethanol, and the centrifugation and washing were repeated 5 times to obtain a precipitate, which was placed in a vacuum drying box and dried at 70 ℃ for 4 h to obtain Cs2TeBr6 microcrystalline powder.
[0047] 2. Preparation of g-C3N4 powder: 10 g of melamine was placed in a tube furnace, the temperature was raised to 600 ℃ at a rate of 5 ℃ / min, and kept at 600 ℃ in an environment full of air for 300 min, and then naturally cooled to room temperature, and the obtained powder was g-C3N4 powder.
[0048] 3. Preparation of composite material (1% Cs2TeBr6 / g-C3N4): The above prepared Cs2TeBr6 microcrystalline powder 0.001 g and g-C3N4 powder 0.099 g were mixed and ground for 10 min.
[0049] Performance test
[0050] Figure 1XRD patterns of the Cs2TeBr6 microcrystalline powder, g-C3N4 powder and the prepared composite material (Cs2TeBr6 / g-C3N4) with stability and good photocatalytic performance in Example 1; Figure 2 SEM images of the Cs2TeBr6 microcrystalline powder (a), g-C3N4 powder (b) and the composite material (Cs2TeBr6 / g-C3N4) with stability and good photocatalytic performance (c) prepared in Example 1; Figure 3 STEM image of the composite material (Cs2TeBr6 / g-C3N4) with stability and good photocatalytic performance prepared in Example 1. Figures 1-3 It can be seen that the composite material (Cs2TeBr6 / g-C3N4) formed by the Cs2TeBr6 microcrystalline powder and the g-C3N4 powder is indeed prepared in Example 1 of the present application.
[0051] Figure 4 SEM images of the composite material (Cs2TeBr6 / g-C3N4) with stability and good photocatalytic performance prepared in Example 2 and Example 3, wherein a and b respectively are. Figure 4 It can be seen that the structures of the composite materials (Cs2TeBr6 / g-C3N4) prepared under different conditions are basically consistent.
[0052] The composite material (5% Cs2TeBr6 / g-C3N4) prepared in Example 2 is used in the photocatalytic reduction experiment of CO2, and the experimental results are as follows: under visible light irradiation, the photocatalytic reduction effect of the composite material (5% Cs2TeBr6 / g-C3N4) on CO2 is the best, and specifically: after 3h of light irradiation, the production rates of CO and CH4 are 468.9 μmol g -1 and 61.31 μmol g -1 -1, respectively. The production rate of CO is 1.5 times and 32 times that of pure Cs2TeBr6 and g-C3N4 in the composite material (5% Cs2TeBr6 / g-C3N4), respectively; the production rate of CH4 is 2 times that of pure Cs2TeBr6 in the composite material (5% Cs2TeBr6 / g-C3N4), and g-C3N4 hardly produces CH4, which indicates that the construction of the composite material (5% Cs2TeBr6 / g-C3N4) with heterojunction helps to further improve the photocatalytic reduction performance of the material on CO2.
[0053] Similarly, the composite material prepared in Example 1 (1% Cs2TeBr6 / g-C3N4), the composite material prepared in Example 3 (9% Cs2TeBr6 / g-C3N4), and the composite material prepared in Example 4 and Example 5 (1% Cs2TeBr6 / g-C3N4) are used in the above-mentioned photocatalytic reduction experiment of CO2, and the results are similar to those of the composite material prepared in Example 2 (5% Cs2TeBr6 / g-C3N4).
[0054] In summary, the application discloses a composite material (Cs2TeBr6 / g-C3N4) which is stable and has good photocatalytic performance, and the composite material (Cs2TeBr6 / g-C3N4) comprises Cs2TeBr6 microcrystal powder and g-C3N4 powder, wherein the mass percentage of the Cs2TeBr6 microcrystal powder in the composite material (Cs2TeBr6 / g-C3N4) is 1% to 9%. The composite material (Cs2TeBr6 / g-C3N4) has good photocatalytic performance and good stability, and has great application potential in the field of photocatalysis. In addition, the preparation method of the composite material (Cs2TeBr6 / g-C3N4) is simple, easy to operate, has low requirements on equipment, low cost, and low energy consumption, and is suitable for large-scale production.
[0055] Finally, it should be pointed out that the above examples are only used to illustrate the technical solutions of the application and are not limiting. Although the application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the application can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions, and all should be covered in the scope of the claims of the application.
Claims
1. A composite material which is stable and has good photocatalytic performance, characterized in that, The composite material comprises Cs2TeBr6 microcrystal powder and g-C3N4 powder, wherein the mass percentage of the Cs2TeBr6 microcrystal powder in the composite material is 1-9%; the g-C3N4 powder is prepared by the following method: melamine is placed in a tube furnace, heated to 600℃, and then kept in an air-filled environment at 600℃ for 300 min, and then naturally cooled to room temperature, and the obtained powder is g-C3N4 powder.
2. The composite material of claim 1, wherein, The mass percentage of the Cs2TeBr6 microcrystal powder in the composite material is 5-9%.
3. The composite material of claim 1, wherein, The Cs2TeBr6 microcrystal powder is prepared by the following method: (1) Cesium bromide and tellurium tetrabromide are added to a sealed container containing hydrogen chloride solution and mixed uniformly; (2) The sealed container in step (1) is placed in an oven and heated to 180℃, and then kept at 180℃ for another 10 h, and then slowly cooled to room temperature within 24 h and taken out; (3) The solution taken out in step (2) is repeatedly washed with anhydrous ethanol, and then centrifuged at a speed of 9000-10000 rpm for 5-6 min, and the supernatant is removed to obtain a precipitate, which is placed in a vacuum drying box and dried at 60-70℃ for 4-5 h to obtain Cs2TeBr6 microcrystal powder.
4. The composite material of claim 3, wherein, The sealed container is a polytetrafluoroethylene autoclave.
5. The composite material of claim 1, wherein, The temperature rising rate of the tube furnace is 5℃ / min.
6. A method of producing the composite material according to any one of claims 1 to 5, characterized by, The Cs2TeBr6 microcrystal powder and the g-C3N4 powder are mixed and ground.
7. The production method according to claim 6, characterized by, The grinding time is 5-10 min.
8. Application of the composite material in photocatalytic reduction of CO2.