CTF-1@Cs3Sb2Br9 composite material and preparation method and application thereof

Abstract

The application belongs to the technical field of catalyst preparation, and relates to a CTF-1@Cs3Sb2Br9 composite material and a preparation method and application thereof, the preparation method comprising the following steps: 1) preparing a covalent organic framework CTF-1; 2) preparing the CTF-1@Cs3Sb2Br9 composite material: 2.1) dissolving CsBr and SbBr3 in a mixed solvent to form a precursor solution; 2.2) adding the prepared CTF-1 into the precursor solution, and ultrasonic treatment to obtain a mixed solution; 2.3) adding the mixed solution into an anti-solvent drop by drop, and stirring, centrifugation and drying to obtain a target product. The CTF-1@Cs3Sb2Br9 composite material can improve the separation efficiency of electron / hole pairs, improve the catalytic efficiency, has the ability of efficiently reducing CO2, and is applied in a CO2 reduction reaction to generate ethane.

Description

Technical Field

[0001] This invention belongs to the field of catalyst preparation technology, and relates to a CTF-1@Cs3Sb2Br9 composite material, its preparation method and application. Background Technology

[0002] The rapid development of manufacturing and industry has increased the consumption of traditional fossil fuels, leading to environmental and ecological problems that have gradually drawn attention. To mitigate the negative impacts of excessive carbon emissions and to achieve CO2 emission reduction during economic transition, research and support for carbon capture, utilization, and storage (CVC) technologies have been intensified. Currently, CO2 has been proven to be converted into higher-value products through biological, chemical, or mineralization processes. For example, CO2 can be used to make dry ice with cooling effects or to prepare fragrances and flavorings. However, existing CO2 conversion processes are typically cumbersome and energy-intensive, thus limiting their application. Photocatalysis, an environmentally friendly green technology widely used in the energy and environmental fields, offers advantages such as cleanliness, no pollution, solar energy as the driving force, and high catalytic efficiency, making it suitable for the photocatalytic reduction of CO2.

[0003] Existing CO2 photoreducing agents, such as halide perovskite materials, have advantages such as adjustable band gap, high quantum yield, and wide light absorption range, and have been widely used in solar cells, light-emitting diodes, and photocatalysis. Among them, lead-free perovskite Cs3Sb2Br9 exhibits higher environmental stability and better catalytic efficiency compared to traditional lead halide perovskites, showing certain application potential in the field of photocatalysis. However, lead-free perovskite Cs3Sb2Br9 also has some drawbacks, such as the need for high temperatures exceeding 200 degrees Celsius for synthesis via traditional hot-injection methods, and a relatively low fluorescence quantum yield (PLQY). In recent years, covalent organic framework materials have emerged as a new type of porous polymer material composed of organic molecules linked by covalent bonds, possessing high chemical and thermal stability, as well as ease of modification and functionalization. Among them, CTF-1 is an organic semiconductor material exhibiting high stability, a suitable band structure for catalysis, and a wide absorption spectrum, and has been widely used in catalysis, gas storage, and other fields. However, as an organic semiconductor, CTF-1 typically has limited crystallinity, and defects easily occur within and between layers, which greatly restricts the transport of photogenerated electrons, leading to high charge transport barriers and sluggish charge dynamics, thereby reducing photocatalytic efficiency. Summary of the Invention

[0004] To address the technical problem of low catalytic efficiency in existing catalytic materials, this invention provides a CTF-1@Cs3Sb2Br9 composite material, its preparation method, and its application. This material improves the separation efficiency of electron / hole pairs, thereby enhancing catalytic efficiency and exhibiting a high-efficiency CO2 reduction capability. Furthermore, the preparation method provided by this invention is simple and easy to industrialize.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for preparing a CTF-1@Cs3Sb2Br9 composite material includes the following steps:

[0007] 1) Preparation of covalent organic framework CTF-1

[0008] 2) Preparation of CTF-1@Cs3Sb2Br9 composite material

[0009] 2.1) CsBr and SbBr3 are dissolved in a mixed solvent to form a precursor solution; the molar ratio of CsBr to SbBr3 is 1:0.6-0.7; the ratio of the mixed solvent to CsBr is 100 ml: 1 mol.

[0010] 2.2) The prepared CTF-1 was added to the precursor solution and ultrasonically treated to obtain a mixture; the mass ratio of CTF-1 to CsBr in the precursor solution was 6.5-7.5:1;

[0011] 2.3) The mixed liquid droplets are added to the antisolvent, stirred, centrifuged and dried to obtain the target product CTF-1@Cs3Sb2Br9 composite material; the volume of the antisolvent is at least 10 times larger than that of the mixed solvent.

[0012] Further specifying, in step 2.1), the mixed solvent is obtained by mixing DMF and DMSO at a volume ratio of 1:0.5 to 1.

[0013] Further specifying, in step 2.2), the ultrasonic treatment time is 1 hour.

[0014] Further specifying that in step 2.3), the stirring time is 5 to 10 minutes; the drying temperature is 120°C to 130°C; and the drying time is 6 to 8 hours.

[0015] Further specifying, step 1) specifically involves synthesizing CTF-1 under a nitrogen atmosphere using terephthalonitrile as a raw material and catalyzed by trifluoromethanesulfonic acid; the ratio of terephthalonitrile to trifluoromethanesulfonic acid is 1g:10ml.

[0016] Further specifying, the synthesis conditions in step 1) are: temperature 100℃~105℃, time 24h~28h.

[0017] Furthermore, step 1) also includes cleaning and drying CTF-1.

[0018] Further specified, the cleaning is carried out sequentially using ammonia, deionized water, ethanol, and dichloromethane; the drying temperature is 40℃~50℃, and the drying time is 12h~24h.

[0019] A method for preparing CTF-1@Cs3Sb2Br9 composite material.

[0020] Application of CTF-1@Cs3Sb2Br9 composite material as a photocatalyst in the CO2 reduction to ethane reaction.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] 1. The CTF-1@Cs3Sb2Br9 composite material prepared by this invention forms an interface region of a zero-dimensional (Cs3Sb2Br9) / two-dimensional (CTF-1) composite structure. Compared with a single photocatalyst, it has the advantages of effectively separating electron-hole pairs, reducing recombination probability, retaining strong redox active sites, and improving photocatalytic activity.

[0023] 2. The CTF-1@Cs3Sb2Br9 composite material prepared by this invention exhibits higher catalytic efficiency in CO2 reduction experiments and has the ability to selectively produce C2H6; thus, it can be inferred that the composite photocatalyst of this invention has the ability to effectively separate electron-hole pairs, reduce recombination probability, and retain strong redox active sites.

[0024] 3. The CTF-1@Cs3Sb2Br9 composite material of the present invention uses lead-free perovskite Cs3Sb2Br9, which has the characteristics of structural stability, environmental friendliness, and green environmental protection.

[0025] 4. This invention introduces the covalent organic framework CTF-1 into lead-free perovskite and successfully prepares a composite photocatalyst using an antisolvent method. It has the potential to be simple to operate, can be prepared in large quantities, and is easy to industrialize. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the CTF-1@Cs3Sb2Br9 composite photocatalyst prepared according to the present invention;

[0027] Figure 2 Lattice analysis of transmission electron microscopy (TEM) images and high-resolution transmission electron microscopy (HRTEM) images of the CTF-1@Cs3Sb2Br9 composite photocatalyst prepared for this invention;

[0028] Figure 3 X-ray diffraction (XRD) pattern of CTF-1@Cs3Sb2Br9 composite photocatalyst for this invention;

[0029] Figure 4 The catalytic activity test data of the CTF-1@Cs3Sb2Br9 composite photocatalyst prepared in this invention in the CO2 reduction experiment. Detailed Implementation

[0030] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0031] The preparation method of CTF-1@Cs3Sb2Br9 composite material provided by the present invention includes the following steps.

[0032] 1) Preparation of covalent organic framework CTF-1

[0033] In this step, CTF-1 is synthesized under a nitrogen atmosphere using terephthalonitrile as a raw material and catalyzed by trifluoromethanesulfonic acid.

[0034] Preferably, the ratio of terephthalonitrile to trifluoromethanesulfonic acid is 1g:10ml.

[0035] Preferably, the synthesis conditions are: temperature 100℃~105℃, time 24h~28h.

[0036] Step 1) also includes cleaning and drying CTF-1.

[0037] Preferably, cleaning is performed using different solutions, including ammonia, deionized water, ethanol, and dichloromethane. Each solution is used to clean 3 to 4 times.

[0038] Preferably, the drying temperature is 40℃~50℃ and the drying time is 12h~24h.

[0039] 2) Preparation of CTF-1@Cs3Sb2Br9 composite material

[0040] 2.1) Dissolve CsBr and SbBr3 in a mixed solvent to form a precursor solution; the molar mass ratio of CsBr to SbBr3 is 1:0.6 to 0.7; the volume ratio of the mixed solvent to CsBr is 100 ml: 1 mol.

[0041] In this step, the mixed solvent is obtained by mixing DMF and DMSO at a volume ratio of 1:0.5 to 1.

[0042] 2.2) The prepared CTF-1 was added to the precursor solution and ultrasonically treated to obtain a mixture; the mass ratio of CTF-1 to CsBr in the precursor solution was 6.5-7.5:1; the ultrasonic treatment time was 1h to 2h.

[0043] 2.3) Add the mixed liquid droplets to the antisolvent, stir, centrifuge and dry to obtain the target product; the volume of the antisolvent is at least 10 times larger than that of the mixed solvent.

[0044] In this step, the stirring time is 5 min to 10 min; the drying temperature is 120℃ to 130℃; and the drying time is 6 h to 8 h.

[0045] The CTF-1@Cs3Sb2Br9 composite material prepared in this invention is used as a photocatalyst in the CO2 reduction to ethane reaction.

[0046] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. In practice, all reagents and pharmaceuticals, unless otherwise specified, are commercially available analytical grade.

[0047] Example 1

[0048] 1) Preparation of covalent organic framework CTF-1

[0049] 1 g of terephthalonitrile was slowly added to a round-bottom flask containing 10 ml of trifluoromethanesulfonic acid, and the flask was sealed after purging with nitrogen. The flask was then placed in a metal bath at 100 °C with magnetic stirring and reacted for 24 h. After the reaction product cooled naturally, it was washed sequentially with ammonia, deionized water, ethanol, and dichloromethane, three times with each solvent. Finally, the collected product was dried in a vacuum drying oven at 40 °C for 24 h to obtain the covalent organic framework CTF-1.

[0050] 2) Preparation of CTF-1@Cs3Sb2Br9 composite material

[0051] 2.1) Dissolve 8.5 mg CsBr and 9.7 mg SbBr3 in a mixed solvent consisting of 3 ml DMF and 1 ml DMSO to obtain a Cs3Sb2Br9 precursor solution.

[0052] 2.2) Subsequently, 60 mg of the prepared CTF-1 was added to the Cs3Sb2Br9 precursor solution and sonicated for 1 h to obtain a mixed solution.

[0053] 2.3) Using toluene as the antisolvent, the above mixed solution was slowly added dropwise to 60 ml of toluene solution under stirring. After stirring for 5 min, the solid reactants were collected by centrifugation and dried in an oven at 120 °C for 6 h. The solid reactants were then thoroughly ground to obtain the CTF-1@Cs3Sb2Br9 composite material.

[0054] Example 2

[0055] 1) Preparation of covalent organic framework CTF-1

[0056] 1 g of terephthalonitrile was slowly added to a round-bottom flask containing 10 ml of trifluoromethanesulfonic acid. Nitrogen gas was introduced, and the flask was sealed. The flask was then placed in a metal bath at 105 °C with magnetic stirring and reacted for 28 h. After the reaction product cooled naturally, it was washed sequentially with ammonia, deionized water, ethanol, and dichloromethane, three times with each solvent. Finally, the collected product was dried in a vacuum oven at 50 °C for 12 h to obtain the covalent organic framework CTF-1.

[0057] 2) Preparation of CTF-1@Cs3Sb2Br9 composite photocatalyst

[0058] First, a Cs3Sb2Br9 precursor solution was prepared using a mixed solvent of DMF and DMSO (volume ratio 3:1) as the solvent for CsBr and SbBr3. The specific procedure was as follows:

[0059] 2.1) Dissolve 8.5 mg CsBr and 9.7 mg SbBr3 in a mixed solvent consisting of 3 ml DMF and 1 ml DMSO.

[0060] 2.2) Subsequently, 60 mg of the prepared CTF-1 was added to the Cs3Sb2Br9 precursor solution and sonicated for 1 h to obtain a mixed solution.

[0061] 2.3) Next, using toluene as the antisolvent, the above mixed solution was slowly added dropwise to 60 ml of toluene solution under stirring. After 10 min, the collected solid reactants were centrifuged and dried in an oven at 130 °C for 8 h, and then thoroughly ground to obtain the CTF-1@Cs3Sb2Br9 composite photocatalyst.

[0062] Example 3

[0063] 1) Preparation of covalent organic framework CTF-1

[0064] 1 g of terephthalonitrile was slowly added to a round-bottom flask containing 10 ml of trifluoromethanesulfonic acid. Nitrogen gas was then introduced, and the flask was sealed. The flask was then placed in a metal bath at 103 °C with magnetic stirring and reacted for 26 h. After the reaction product cooled naturally, it was washed sequentially with ammonia, deionized water, ethanol, and dichloromethane, three times with each solvent. Finally, the collected product was dried in a vacuum oven at 45 °C for 16 h to obtain the covalent organic framework CTF-1.

[0065] 2) Preparation of CTF-1@Cs3Sb2Br9 composite photocatalyst

[0066] First, a Cs3Sb2Br9 precursor solution was prepared using a mixed solvent of DMF and DMSO (volume ratio 3:2) as the solvent for CsBr and SbBr3. The specific procedure was as follows:

[0067] 2.1) Dissolve 8.5 mg CsBr and 9.7 mg SbBr3 in a mixed solvent consisting of 3 ml DMF and 1 ml DMSO.

[0068] 2.2) Subsequently, 60 mg of the prepared CTF-1 was added to the Cs3Sb2Br9 precursor solution and sonicated for 1 h to obtain a mixed solution.

[0069] 2.3) Next, using toluene as the antisolvent, the above mixed solution was slowly added dropwise to 80 ml of toluene solution under stirring. After stirring for 8 min, the solid reactants were collected by centrifugation and dried in an oven at 125 °C for 8 h. Then, the solid reactants were thoroughly ground to obtain the CTF-1@Cs3Sb2Br9 composite photocatalyst.

[0070] Example 4

[0071] 1) Preparation of covalent organic framework CTF-1

[0072] 1 g of terephthalonitrile was slowly added to a round-bottom flask containing 10 ml of trifluoromethanesulfonic acid. Nitrogen gas was introduced, and the flask was sealed. The flask was then placed in a metal bath at 104 °C with magnetic stirring and reacted for 27 h. After the reaction product cooled naturally, it was washed sequentially with ammonia, deionized water, ethanol, and dichloromethane, five times with each solvent. Finally, the collected product was dried in a vacuum oven at 46 °C for 20 h to obtain the covalent organic framework CTF-1.

[0073] 2) Preparation of CTF-1@Cs3Sb2Br9 composite photocatalyst

[0074] First, a Cs3Sb2Br9 precursor solution was prepared using a mixed solvent of DMF and DMSO (volume ratio 3:1) as the solvent for CsBr and SbBr3. The specific procedure was as follows:

[0075] 2.1) Dissolve 8.5 mg CsBr and 9.7 mg SbBr3 in a mixed solvent consisting of 3 ml DMF and 1 ml DMSO.

[0076] 2.2) Subsequently, 60 mg of the prepared CTF-1 was added to the Cs3Sb2Br9 precursor solution and sonicated for 1 h to obtain a mixed solution.

[0077] 2.3) Next, using toluene as the antisolvent, the above mixed solution was slowly added dropwise to 80 ml of toluene solution under stirring. After stirring for 7 min, the solid reactant was collected by centrifugation and dried in an oven at 127 °C for 6 h. Then, it was thoroughly ground to obtain the CTF-1@Cs3Sb2Br9 composite photocatalyst.

[0078] Comparative Example 1

[0079] Preparation of covalent organic framework CTF-1.

[0080] The preparation method is the same as that in Example 1.

[0081] Comparative Example 2

[0082] Synthesis of lead-free perovskite Cs3Sb2Br9

[0083] Lead-free perovskite Cs3Sb2Br9 was prepared using a reverse solvent method.

[0084] First, a Cs3Sb2Br9 precursor solution was prepared (consistent with that in Example 1). Then, the prepared precursor solution was slowly added dropwise to 60 ml of toluene solution under stirring. After stirring for 5 min, the solid reactants were separated by centrifugation. Subsequently, the reactants were dried in an oven at 120 °C for 6 h. Finally, after thorough grinding, Cs3Sb2Br9 perovskite material was obtained.

[0085] The performance of the composite material was verified through the following tests.

[0086] Verification 1

[0087] The CTF-1@Cs3Sb2Br9 composite material prepared in Example 1 was subjected to structural testing. The resulting structural schematic diagram is shown below. Figure 1 As shown.

[0088] from Figure 1It can be observed that Cs3Sb2Br9 nanocrystals are densely loaded on CTF-1, where the basic unit of CTF-1 is a multi-ring structure formed by terephthalonitrile, and then the multi-rings are orderly interconnected to form a two-dimensional planar structure; while the Cs3Sb2Br9 nanocrystal has low crystal symmetry, belongs to the trigonal crystal system, and has the space group Pml (no. 164).

[0089] Verification 2

[0090] The CTF-1@Cs3Sb2Br9 composite material prepared in Example 1 was subjected to TEM testing. The obtained TEM images are shown below. Figure 2 As shown.

[0091] from Figure 2 It can be seen that, Figure 2 ac demonstrated that Cs3Sb2Br9 nanocrystals were densely loaded on layered CTF-1, and Figure 1 Schematic diagram of the middle structure Figure 1 To.

[0092] Figure 2 Image d shows the HRTEM image of Cs3Sb2Br9 nanocrystals loaded on CTF-1 and the corresponding lattice spacing analysis. The measured lattice spacing is 0.69 nm, which corresponds to the Cs3Sb2Br9 (100) crystal plane. TEM and HRTEM analyses confirm the successful preparation of the CTF-1@Cs3Sb2Br9 composite photocatalyst.

[0093] Verification 3

[0094] XRD tests were performed on the CTF-1@Cs3Sb2Br9 composite material prepared in Example 1. The obtained XRD pattern was compared with the Cs3Sb2Br9 standard card, and the results are as follows: Figure 3 As shown.

[0095] from Figure 3 The peaks marked with crosses at 17.9° and 23.5° are typical CTF-1 diffraction peaks. The other sharp peaks are diffraction signals belonging to Cs3Sb2Br9, and correspond well with the standard Cs3Sb2Br9 card (ICSD No. 009-0964). The XRD data further confirms the successful loading of Cs3Sb2Br9 onto CTF-1 and reflects a high degree of crystallinity of Cs3Sb2Br9.

[0096] Verification of 4 catalytic performance

[0097] Test samples: CTF-1@Cs3Sb2Br9 composite material prepared in Example 1; CTF-1 prepared in Comparative Example 1 and Cs3Sb2Br9 perovskite materials prepared in Comparative Example 2.

[0098] The above-mentioned test samples were used as photocatalysts in the reduction of CO2 gas. The specific experimental process is as follows.

[0099] 20 mg of photocatalyst was weighed and dispersed in a mixed solvent of ethyl acetate and water, with a volume ratio of ethyl acetate / water of 99 mL / 1 mL. 10% triethylamine was added to the mixed solvent as a sacrificial agent. The catalyst was dispersed into a particulate suspension by magnetic stirring and ultrasonication. The suspension was added to a quartz glass reactor equipped with a condenser circulating water system. Ar gas was introduced at a flow rate of 20 sccm for 10 min to fully replace the air, followed by the introduction of high-purity CO2 gas (5N) at a flow rate of 15 sccm. A 300W xenon lamp with a 420 nm cutoff filter was used as the light source, and irradiation began after preheating for 10 min. Light intensity: 230 mW / cm² 2 The incident area is 19.625 cm². 2 The reaction products were analyzed using an Agilent GC7890 (FID and TCD). The catalytic activity data of the photocatalyst in the CO2 reduction experiment are as follows: Figure 4 As shown; where: Figure 4 a. Comparison of CTF-1@Cs3Sb2Br9, the products and formation rates of CO2 photocatalytic reduction by CTF-1 and Cs3Sb2Br9; Figure 4 b is the curve showing the change in product content of CTF-1@Cs3Sb2Br9 over time during photocatalytic reduction of CO2.

[0100] Depend on Figure 4 As can be seen from this, the formation rates of the target products (CO, CH4, C2H6) of pure Cs3Sb2Br9 and CTF-1 are both less than 0.75 μmol·g. -1 ·h -1 However, the catalytic efficiency of the CTF-1@Cs3Sb2Br9 composite photocatalyst was significantly improved, with the formation rate of the target products (CO, CH4, C2H6) exceeding 5 μmol·g. -1 ·h -1 The rate of ethane formation was 2.68 μmol·g⁻¹. -1 ·h -1 The rate of formation of methane is much higher than that of methane (0.54 μmol·g). -1 ·h -1 ).

[0101] The improved catalytic efficiency of the catalyst prepared in this invention is mainly due to the heterostructure of CTF-1@Cs3Sb2Br9, which enhances the separation efficiency of electron / hole pairs, reduces the recombination probability, and thus improves the catalytic efficiency. Therefore, it can be inferred that the composite photocatalyst of this invention has the properties of effectively separating electron-hole pairs, reducing the recombination probability, and retaining strong redox active sites.

[0102] The reason for the selective formation of ethane is that the catalytic reaction intermediate ·CH3 tends to combine with ·CH3 to form ethane, rather than with H. + The combination generates CH4, which is similar to the g-C3N4-based heterojunction catalyst, i.e., CTF-1 has the effect of stabilizing ·CH3, making it easy for ·CH3 to react with each other to generate C2H6.

[0103] Depend on Figure 4 b indicates that the CH4 production reached 1.2 μmol·g in the first 20 minutes. -1 Then the increase stopped, while the production of CO and C2H6 continued to increase, but the rate gradually slowed down; this indicates that when the catalyst of the present invention is used in the CO2 reduction reaction, a large amount of CO2 is reduced to ethane, and the selectivity for ethane is high.

Claims

1. A method for preparing a CTF-1@Cs3Sb2Br9 composite material, characterized in that, Comprising the following steps: 1) preparing covalent organic framework CTF-1 The step 1) is specifically synthesizing CTF-1 under nitrogen atmosphere, using terephthalonitrile as raw material, and trifluoromethanesulfonic acid as catalyst; the use amount ratio of terephthalonitrile and trifluoromethanesulfonic acid is 1g:10mL; the synthesis condition in the step 1) is: temperature 100℃~105℃, time 24h~28h; 2) preparing CTF-1@Cs3Sb2Br9 composite material 2.1) dissolving CsBr and SbBr3 in mixed solvent to form precursor solution; the molar mass ratio of CsBr and SbBr3 is 1:0.6~0.7; the use amount ratio of mixed solvent and CsBr is 100mL:1mol; 2.2) adding prepared CTF-1 into the precursor solution, and ultrasonic treatment to obtain mixed solution; the mass ratio of CTF-1 and CsBr in the precursor solution is 6.5-7.5:1; 2.3) adding the mixed solution into anti-solvent dropwise, and stirring, centrifugation and drying to obtain the target product CTF-1@Cs3Sb2Br9 composite material; the volume of anti-solvent is at least 10 times larger than that of mixed solvent.

2. The method for preparing the CTF-1@Cs3Sb2Br9 composite material according to claim 1, characterized in that, In the step 2.1), the mixed solvent is obtained by mixing DMF and DMSO according to the volume ratio of 1:0.5~1.

3. The method for preparing the CTF-1@Cs3Sb2Br9 composite material according to claim 1, characterized in that, In the step 2.2), the ultrasonic treatment time is 1h~2h.

4. The method of claim 1, wherein the CTF-1@Cs3Sb2Br9 composite material is prepared by the following steps of: In the step 2.3), the stirring time is 5min~10min; the drying temperature is 120℃~130℃, and the drying time is 6h~8h.

5. The method of claim 1, wherein the CTF-1@Cs3Sb2Br9 composite material is prepared by the following steps of: The step 1) further comprises washing and drying treatment of CTF-1.

6. The method of claim 5, wherein the CTF-1@Cs3Sb2Br9 composite material is prepared by the following steps of: The washing is performed in sequence using ammonia water, deionized water, ethanol and dichloromethane; the drying temperature of step 1) is 40℃~50℃, and the drying time is 12h~24h.

7. A CTF-1@Cs3Sb2Br9 composite material prepared by the preparation method of the CTF-1@Cs3Sb2Br9 composite material according to any one of claims 1-6.

8. Application of the CTF-1@Cs3Sb2Br9 composite material according to claim 7 as photocatalyst in the reaction of CO2 reduction to generate ethane.

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