A dibromobismuth silver acid dicyesium / metal organic framework MIL-53Fe heterojunction photocatalyst as well as a preparation method and application thereof
By constructing a heterojunction photocatalyst of cesium hexabromobismuth silanoate/metal-organic framework MIL-53Fe, the problems of high recombination rate of photogenerated carriers and insufficient structural stability were solved, achieving a highly efficient carbon dioxide photocatalytic reduction effect, which is suitable for large-scale application.
Patent Information
- Application Number
- CN202610894604.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-22
- Publication Date
- 2026-07-24
AI Technical Summary
In the existing technology, pure-phase MIL-53Fe photocatalysts have high photogenerated carrier recombination rate, poor charge transport performance, low catalytic activity, single product, and insufficient cycle stability. Cesium hexabromobismuth silanoate has poor structural stability in polar solvents, which limits its application in the field of carbon dioxide photocatalytic reduction.
A heterojunction photocatalyst was constructed by combining hexabromobismuth silanoate dicesium with a metal-organic framework MIL-53Fe and prepared by mechanical stirring. This heterojunction structure was used to suppress photogenerated carrier recombination and improve charge separation and migration efficiency.
It significantly improves the activity and stability of photocatalytic reduction of carbon dioxide. The synergistic advantages of the materials, such as visible light capture capability and large specific surface area, enable efficient CO2 adsorption and activation. The preparation method is simple, cost-controllable, and suitable for large-scale application.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of photocatalytic materials technology, specifically relating to a hexabromobismuth silanoate dicesium / metal-organic framework MIL-53Fe heterojunction photocatalyst, its preparation method, and its application. Background Technology
[0002] In recent years, massive carbon dioxide emissions have exacerbated the global greenhouse effect, leading to a series of environmental and social problems. Photocatalytic carbon dioxide reduction uses inexhaustible solar energy to directly convert carbon dioxide gas into hydrocarbon solar fuels, making it a feasible method to simultaneously address the energy crisis and environmental pollution.
[0003] Metal-organic frameworks (MOFs) possess large specific surface areas and unique metal-ligand structures, exhibiting excellent adsorption capacity for carbon dioxide. MIL-53Fe, a typical representative of iron-based MOFs, contains numerous Fe–O clusters in its framework. Its advantages, including good light absorption, abundant active sites, excellent carbon dioxide adsorption performance, low preparation cost, and tunable structural characteristics, have led to its widespread research and application in the photocatalytic reduction of carbon dioxide. However, pure-phase MIL-53Fe suffers from drawbacks such as high photogenerated carrier recombination rate, poor charge transport performance, low catalytic activity, single product, and insufficient cycling stability, which significantly limit its practical application in carbon dioxide photocatalytic reduction systems.
[0004] Lead-free double perovskite bismuth silanate dicesium hexabromobismuth argonate (Cs₂AgBiBr₆) has become a promising new catalytic material for photocatalytic CO₂ reduction due to its advantages such as low toxicity and environmental friendliness, excellent visible light harvesting ability, adaptable band structure, good structural stability, and ease of constructing composite heterojunctions. However, it also suffers from shortcomings such as weak CO₂ adsorption and activation ability, fast recombination rate of photogenerated carriers, and poor structural stability in polar solvents, which severely limit its photocatalytic performance and practical applications.
[0005] Therefore, constructing a heterojunction composite material by combining cesium hexabromobismuth silanoate with the iron-based metal-organic framework material MIL-53Fe can effectively suppress photogenerated carrier recombination, accelerate charge separation and migration, and thus significantly improve the overall photocatalytic CO2 reduction activity of the system. Summary of the Invention
[0006] This invention addresses the shortcomings of existing technologies by providing a hexabromobismuth silanoate dicesium / metal-organic framework MIL-53Fe heterojunction photocatalyst, its preparation method, and its application. This method is simple, convenient, low-cost, and operates under mild conditions, which is conducive to large-scale production. The obtained hexabromobismuth silanoate dicesium / metal-organic framework MIL-53Fe photocatalyst exhibits excellent photocatalytic reduction activity of carbon dioxide.
[0007] To solve the above problems, the technical solution of the present invention is as follows: a hexabromobismuth silanoate dicesium / metal-organic framework MIL-53Fe heterojunction photocatalyst, wherein the mass ratio of hexabromobismuth silanoate dicesium to metal-organic framework MIL-53Fe is 1:3 to 1:5.
[0008] A method for preparing a cesium hexabromobismuth silanoate / metal-organic framework MIL-53Fe heterojunction photocatalyst includes the following steps.
[0009] 1) Ferric chloride hexahydrate and 1,4-benzenedicarboxylic acid were dissolved in dimethylformamide and stirred to obtain a mixed solution. The solution was subjected to a hydrothermal reaction. After cooling, washing and drying, the metal-organic framework MIL-53Fe was obtained. Hydrobromic acid was preheated, and silver bromide and bismuth bromide were added to the preheated hydrobromic acid. After complete dissolution, cesium bromide was added and stirred continuously. The solution was kept warm, cooled and dried to obtain dicesium hexabromobismuth silanoate.
[0010] 2) Dissolve the metal-organic framework MIL-53Fe and dicesium hexabromobismuth silanoate in anhydrous ethanol, stir, sonicate, centrifuge and dry to obtain the dicesium hexabromobismuth silanoate / metal-organic framework MIL-53Fe heterojunction photocatalyst.
[0011] In the preparation method of the above-mentioned hexabromobismuth silanoate dicesium / metal-organic framework MIL-53Fe heterojunction photocatalyst, in step 1), the ratio of ferric chloride hexahydrate: 1,4-benzenediacarboxylic acid: dimethylformamide is 4~6 mmol: 4~6 mmol: 25~35 ml.
[0012] In the preparation method of the above-mentioned hexabromobismuth silanoate dicesium / metal-organic framework MIL-53Fe heterojunction photocatalyst, in step 1), the stirring time is 30 min, the hydrothermal reaction temperature is 180℃, and the hydrothermal reaction time is 13 h.
[0013] In the preparation method of the above-mentioned hexabromobismuth silver dicesium / metal-organic framework MIL-53Fe heterojunction photocatalyst, in step 1), the ratio of hydrobromic acid: silver bromide: bismuth bromide: cesium bromide is 25~35 ml: 1~3 mmol: 0.2~0.4 mmol: 3~5 mmol.
[0014] In the preparation method of the above-mentioned hexabromobismuth silanoate dicesium / metal-organic framework MIL-53Fe heterojunction photocatalyst, in step 1), the hydrobromic acid is a 48wt% hydrobromic acid aqueous solution, the preheating temperature is 110℃, the holding time is 3h, the cooling temperature is 25℃, and the drying temperature is 60℃.
[0015] In the preparation method of the above-mentioned hexabromobismuth silanoic acid dicesium / metal-organic framework MIL-53Fe heterojunction photocatalyst, in step 2), the stirring time is 1 hour, the ultrasonic time is 30 minutes, the number of centrifugations is 1, and the drying temperature is 60℃.
[0016] Application of the above-mentioned hexabromobismuth silanoate dicesium / metal-organic framework MIL-53Fe heterojunction photocatalyst in photocatalytic reduction of carbon dioxide.
[0017] The above application is carried out as follows: Under visible light irradiation, the hexabromobismuth silanoate dicesium / metal-organic framework MIL-53Fe heterojunction photocatalyst and deionized water are placed in a sealed space filled with carbon dioxide gas to reduce the carbon dioxide gas to carbon monoxide gas.
[0018] The beneficial effects of the present invention.
[0019] 1. This invention utilizes a mechanical stirring method to prepare a cesium hexabromobismuth silanoate / metal-organic framework MIL-53Fe heterojunction photocatalyst. The heterojunction structure of this material effectively suppresses the recombination of photogenerated carriers and significantly improves the efficiency of charge separation and migration, thereby achieving the goal of improving photocatalytic activity.
[0020] 2. This invention utilizes a mechanical stirring method to construct a hexabromobismuth silanoate dicesium / metal-organic framework MIL-53Fe heterojunction photocatalyst, which fully leverages the synergistic advantages of the two materials: hexabromobismuth silanoate dicesium has excellent visible light harvesting ability and a suitable band structure, providing sufficient photogenerated carriers for the reaction; iron-based metal-organic framework MIL-53Fe has a large specific surface area, abundant Fe-O active sites, and excellent CO2 adsorption performance, which can significantly improve the adsorption and activation capacity of CO2. The combination of the two effectively compensates for the shortcomings of a single component.
[0021] 3. The hexabromobismuth silanoate dicesium / metal-organic framework MIL-53Fe heterojunction photocatalyst prepared by this invention has stronger photocatalytic reduction ability, can participate in CO2 reduction reaction efficiently, and exhibits excellent catalytic activity and stability; moreover, the preparation method is simple to operate, mild under mild conditions, and controllable in cost, which is conducive to large-scale preparation and practical application. Attached Figure Description
[0022] Figure 1 XRD patterns of CABB, MIL-53Fe, CABBFe-3, CABBFe-4, and CABBFe-5.
[0023] Figure 2 This is a SEM image of MIL-53Fe.
[0024] Figure 3 This is a SEM image of CABB.
[0025] Figure 4 This is a SEM image of CABBFe-4.
[0026] Figure 5Comparison of photocatalytic reduction of carbon dioxide reactions for CABB, MIL-53Fe, CABBFe-3, CABBFe-4, and CABBFe-5.
[0027] Figure 6 A comparison of the photocatalytic reduction activities of CABB, MIL-53Fe, CABBFe-3, CABBFe-4, and CABBFe-5 for carbon dioxide.
[0028] Figure 7 PL plots for CABB, MIL-53Fe, CABBFe-3, CABBFe-4, and CABBFe-5. Detailed Implementation
[0029] Example 1: Preparation of the metal-organic framework MIL-53Fe.
[0030] 5 mmol of ferric chloride hexahydrate and 5 mmol of 1,4-benzenediacarboxylic acid were dissolved in 30 mL of dimethylformamide and stirred for 30 minutes. The mixture was then poured into a 50 mL stainless steel autoclave lined with polytetrafluoroethylene and subjected to a hydrothermal reaction at 180°C for 13 h. Upon cooling to room temperature, the orange powder MIL-53Fe was thoroughly washed repeatedly with dimethylformamide and anhydrous ethanol, and then dried overnight at 60°C. After cooling to room temperature, MIL-53Fe was obtained.
[0031] Example 2: Preparation of dicesium hexabromobismuth silver acid (CABB).
[0032] First, preheat 30 mL of 48 wt% hydrobromic acid to 110°C, add 2 mmol of silver bromide and 0.3 mmol of bismuth bromide, and after they are completely dissolved, slowly add 4 mmol of cesium bromide while stirring continuously. Keep the mixture at 110°C for 3 hours, then cool it to room temperature (25°C) and dry it under vacuum at 60°C overnight to obtain CABB.
[0033] Example 3: A cesium hexabromobismuth silanoate / metal-organic framework MIL-53Fe photocatalyst (the mass ratio of cesium hexabromobismuth silanoate to MIL-53Fe is 1:3).
[0034] 0.03 g of the metal-organic framework MIL-53Fe prepared in Example 1 and 0.01 g of dicesium hexabromobismuth silanoate (CABB) prepared in Example 2 were dissolved in 50 mL of anhydrous ethanol, stirred for 1 h, sonicated for 30 min, centrifuged, and then dried at 60 °C overnight. After cooling to room temperature, the dicesium hexabromobismuth silanoate / metal-organic framework MIL-53Fe composite material (denoted as CABBFe-3) was obtained.
[0035] The MIL-53Fe, CABB, and CABBFe-3 prepared in Examples 1, 2, and 3 were subjected to XRD and PL tests. The test results are as follows: Figure 1 and Figure 7 As shown in the figure, typical characteristic peaks of CABB and MIL-53Fe were detected in CABBFe-3, indicating the successful preparation of CABBFe-3.
[0036] Example 4: Photocatalytic reduction of carbon dioxide using CABBFe-3 photocatalyst.
[0037] The CABBFe-3 photocatalyst prepared in Example 3 was used to conduct a photocatalytic reduction experiment of carbon dioxide. The test procedure was as follows: using a 300W xenon lamp as the light source, 0.01g of the prepared CABB, MIL-53Fe, and CABBFe-3 were placed in a sealed reaction vessel along with 1mL of deionized water. A vacuum pump was used to evacuate the sealed vessel, and carbon dioxide gas was passed through the vessel three times. Then, carbon dioxide was reduced under visible light irradiation. Figure 5 , 6 As shown, the cesium dibromobismuth silanoate / metal-organic framework MIL-53Fe photocatalyst prepared in Example 3 exhibits good photocatalytic activity and stability, with a carbon monoxide generation rate of 10.99 μmol•g. -1 •h -1 The carbon monoxide formation rate of MIL-53Fe is only 8.89 μmol•g. -1 •h -1 .
[0038] Example 5: A cesium hexabromobismuth silanoate / metal-organic framework MIL-53Fe photocatalyst (the mass ratio of cesium hexabromobismuth silanoate to MIL-53Fe is 1:4).
[0039] 0.04 g of the metal-organic framework MIL-53Fe prepared in Example 1 and 0.01 g of dicesium hexabromobismuth silanoate (CABB) prepared in Example 2 were dissolved in 50 mL of anhydrous ethanol, stirred for 1 h, sonicated for 30 min, centrifuged, and then dried at 60 °C overnight. After cooling to room temperature, the dicesium hexabromobismuth silanoate / metal-organic framework MIL-53Fe composite material (denoted as CABBFe-4) was obtained.
[0040] The CABBFe-4 prepared in Example 5 was subjected to XRD and PL tests, and the test results are as follows: Figure 1 and Figure 7 As shown in the figure, typical characteristic peaks of CABB and MIL-53Fe were detected in CABBFe-4, indicating the successful preparation of CABBFe-4.
[0041] SEM tests were performed on MIL-53Fe, CABB, and CABBFe-4, such as... Figure 2 , Figure 3 and Figure 4 As shown, MIL-53Fe exhibits a porous and fluffy flocculent structure, while CABB has a blocky structure. The surface of CABB is uniformly loaded with nanoscale particles of MIL-53Fe, indicating the successful synthesis of CABBFe-4.
[0042] Example 6: Photocatalytic reduction of carbon dioxide using CABBFe-4 photocatalyst.
[0043] The CABBFe-4 photocatalyst prepared in Example 5 was used to conduct a photocatalytic reduction experiment of carbon dioxide. The test procedure was as follows: using a 300W xenon lamp as the light source, 0.01g of the prepared hm-CN, MIL-53Fe, and CABBFe-4 were placed in a sealed reaction vessel along with 1mL of deionized water. A vacuum pump was used to evacuate the sealed vessel, and carbon dioxide gas was passed through the vessel three times. Then, carbon dioxide was reduced under visible light irradiation. Figure 5 , 6 As shown, the cesium dibromobismuth silanoate / metal-organic framework MIL-53Fe photocatalyst prepared in Example 5 exhibits good photocatalytic activity and stability, with a carbon monoxide generation rate of 15.06 μmol•g for CABBFe-4. -1 •h -1 The carbon monoxide formation rate of MIL-53Fe is only 8.89 μmol•g. -1 •h -1 .
[0044] Example 7: A cesium hexabromobismuth silanoate / metal-organic framework MIL-53Fe photocatalyst (the mass ratio of cesium hexabromobismuth silanoate to MIL-53Fe is 1:5).
[0045] 0.05 g of the metal-organic framework MIL-53Fe prepared in Example 1 and 0.01 g of dicesium hexabromobismuth silanoate (CABB) prepared in Example 2 were dissolved in 50 mL of anhydrous ethanol, stirred for 1 h, sonicated for 30 min, centrifuged, and then dried at 60 °C overnight. After cooling to room temperature, the dicesium hexabromobismuth silanoate / metal-organic framework MIL-53Fe composite material (denoted as CABBFe-5) was obtained.
[0046] The CABBFe-5 prepared in Example 7 was subjected to XRD and PL tests, and the test results are as follows: Figure 1 and Figure 7 As shown in the figure, typical characteristic peaks of CABB and MIL-53Fe were detected in CABBFe-5, indicating the successful preparation of CABBFe-5.
[0047] Example 8: Photocatalytic reduction of carbon dioxide using CABBFe-5 photocatalyst.
[0048] The CABBFe-5 photocatalyst prepared in Example 7 was used to conduct a photocatalytic reduction experiment of carbon dioxide. The test procedure was as follows: using a 300W xenon lamp as the light source, 0.01g of the prepared CABB, MIL-53Fe, and CABBFe-5 were placed in a sealed reaction vessel along with 1mL of deionized water. A vacuum pump was used to evacuate the sealed vessel, and carbon dioxide gas was passed through the vessel three times. Then, carbon dioxide was reduced under visible light irradiation. Figure 5 , 6 As shown, the cesium dibromobismuth silanoate / metal-organic framework MIL-53Fe photocatalyst prepared in Example 7 exhibits good photocatalytic activity and stability, with a carbon monoxide generation rate of 11.57 μmol•g. -1 •h -1 The carbon monoxide formation rate of MIL-53Fe is only 8.89 μmol•g. -1 •h -1 .
Claims
1. A hexabromobismuth silanoic acid dicesium / metal-organic framework MIL-53Fe heterojunction photocatalyst, characterized in that, The mass ratio of the dicesium hexabromobismuth silanoate to the metal-organic framework MIL-53Fe is 1:3 to 1:
5.
2. A method for preparing the hexabromobismuth silanoic acid dicesium / metal-organic framework MIL-53Fe heterojunction photocatalyst according to claim 1, characterized in that, Includes the following steps: 1) Ferric chloride hexahydrate and 1,4-benzenedicarboxylic acid were dissolved in dimethylformamide and stirred to obtain a mixed solution. The solution was subjected to a hydrothermal reaction. After cooling, washing, and drying, the metal-organic framework MIL-53Fe was obtained. Hydrobromic acid was preheated, and silver bromide and bismuth bromide were added to the preheated hydrobromic acid. After complete dissolution, cesium bromide was added and stirred continuously. The solution was kept warm, cooled, and dried to obtain dicesium hexabromobismuth silanate. 2) Dissolve the metal-organic framework MIL-53Fe and dicesium hexabromobismuth silanoate in anhydrous ethanol, stir, sonicate, centrifuge and dry to obtain the dicesium hexabromobismuth silanoate / metal-organic framework MIL-53Fe heterojunction photocatalyst.
3. The preparation method of the hexabromobismuth silanoate dicesium / metal-organic framework MIL-53Fe heterojunction photocatalyst according to claim 2, characterized in that, In step 1), the ratio of ferric chloride hexahydrate: 1,4-benzenediacarboxylic acid: dimethylformamide is 4~6 mmol: 4~6 mmol: 25~35 ml.
4. The preparation method of the hexabromobismuth silanoate dicesium / metal-organic framework MIL-53Fe heterojunction photocatalyst according to claim 2, characterized in that, In step 1), the stirring time is 30 minutes, the hydrothermal reaction temperature is 180°C, and the hydrothermal reaction time is 13 hours.
5. The preparation method of the hexabromobismuth silanoate dicesium / metal-organic framework MIL-53Fe heterojunction photocatalyst according to claim 2, characterized in that, In step 1), the ratio of hydrobromic acid: silver bromide: bismuth bromide: cesium bromide is 25~35 ml: 1~3 mmol: 0.2~0.4 mmol: 3~5 mmol.
6. The preparation method of the hexabromobismuth silanoate dicesium / metal-organic framework MIL-53Fe heterojunction photocatalyst according to claim 2, characterized in that, In step 1), the hydrobromic acid is a 48wt% aqueous solution of hydrobromic acid, the preheating temperature is 110℃, the holding time is 3h, the cooling temperature is 25℃, and the drying temperature is 60℃.
7. The preparation method of the hexabromobismuth silanoate dicesium / metal-organic framework MIL-53Fe heterojunction photocatalyst according to claim 2, characterized in that, In step 2), the stirring time is 1 hour, the ultrasonic time is 30 minutes, the centrifugation is performed once, and the drying temperature is 60℃.
8. The application of the hexabromobismuth silanoate dicesium / metal-organic framework MIL-53Fe heterojunction photocatalyst according to claim 1 in the photocatalytic reduction of carbon dioxide.
9. The application of the hexabromobismuth silanoate dicesium / metal-organic framework MIL-53Fe heterojunction photocatalyst according to claim 8 in the photocatalytic reduction of carbon dioxide, characterized in that, The method is as follows: Under visible light irradiation, the hexabromobismuth silanoate dicesium / metal-organic framework MIL-53Fe heterojunction photocatalyst and deionized water are placed in a sealed space filled with carbon dioxide gas to reduce the carbon dioxide gas to carbon monoxide gas.