Preparation method and application of chromium-doped fullerene C20 catalyst
By using chromium-doped fullerene C20 catalyst, the problems of insufficient activity and stability of existing catalysts in carbon dioxide hydrogenation reaction have been solved, achieving efficient carbon dioxide conversion and formic acid production, with high activity, high selectivity and high stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-26
- Publication Date
- 2026-04-03
AI Technical Summary
Existing catalysts for carbon dioxide hydrogenation are expensive, have weak catalytic activity, and poor stability, making it difficult to meet the needs of industrial applications.
Using chromium-doped fullerene C20 catalyst, a uniform suspension was formed by dispersing fullerene C20 as a support with toluene and ultrasonic treatment, and then doped with chromium trichloride under nitrogen protection to build a strong electronic coupling between chromium atoms and the C20 carbon cage structure.
It achieves a carbon dioxide conversion rate of up to 90.2% and a formic acid yield of up to 92.6% under mild conditions, and the catalytic activity remains above 91.7% after five cycles, demonstrating high activity, high selectivity and high stability.
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Figure CN121775880A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of novel catalytic materials technology, and in particular to a method for preparing a chromium-doped fullerene C20 catalyst and its application. Background Technology
[0002] Carbon dioxide hydrogenation is a key pathway to achieving carbon resource recycling and mitigating the greenhouse effect. Its products, such as methanol, formic acid, and methane, can serve as clean energy carriers or important chemical raw materials, possessing significant application value in the energy and chemical industries. The catalytic system is the core of the carbon dioxide hydrogenation reaction. Currently, mainstream catalytic materials mainly include noble metal-based catalysts, transition metal oxide catalysts, and carbon-based catalysts. However, these catalysts have many shortcomings, such as high cost, weak catalytic activity, and poor stability, making it difficult to meet the demands of industrial applications. Therefore, developing a low-cost, highly active, highly stable catalytic system capable of achieving efficient carbon dioxide hydrogenation under mild conditions has become a critical problem urgently needing to be solved in this field. Summary of the Invention
[0003] To address the aforementioned problems, this invention proposes a method for preparing a chromium-doped fullerene C20 catalyst and its application. This catalyst has the advantages of high activity, high selectivity, and high stability, providing a new material for the efficient resource utilization of carbon dioxide.
[0004] The present invention provides a method for preparing a chromium-doped fullerene C20 catalyst and its application, comprising the following steps: Step 1: Disperse fullerene C20 in toluene, sonicate to form a uniform suspension, add chromium trichloride, and carry out the doping reaction under nitrogen protection. After the reaction is completed, centrifuge to separate the product, wash with toluene, and dry to obtain chromium-doped fullerene C20 catalyst.
[0005] Step 2: In the reaction vessel, add deionized water, chromium-doped fullerene C20 catalyst, hydrogen, and carbon dioxide in the ratio of (200-400) mL: 1 g: (1-3) mol: 1 mol, stir the reaction, cool after the reaction is complete, and collect the reaction product containing formic acid.
[0006] Preferably, the ultrasonic treatment time in step 1 is 30-50 minutes.
[0007] Preferably, the doping reaction in step 1 is carried out at a temperature of 60-100℃ for 2-6 hours.
[0008] Preferably, the drying temperature in step 1 is 60-90℃ and the drying time is 10-20 h.
[0009] Preferably, in step 1, the molar ratio of fullerene C20 to chromium trichloride is (5-15):1.
[0010] Preferably, in step 2, the temperature of the stirring reaction is 80-120℃, the time is 4-8 h, the stirring rate is 400-600 rpm, and the total pressure is 0.5-1.5 MPa.
[0011] The beneficial effects of this invention are: This invention utilizes fullerene C20 as a support, disperses it in toluene, and ultrasonically treats it to form a homogeneous suspension. Under nitrogen protection, it undergoes a doping reaction with chromium trichloride, successfully constructing a stable active center with strong electronic coupling between chromium atoms and the C20 carbon cage structure. This method is simple and operates under mild conditions. The prepared chromium-doped fullerene C20 catalyst exhibits excellent catalytic performance in the hydrogenation of carbon dioxide to formic acid. Under mild conditions, it achieves a maximum carbon dioxide conversion rate of 90.2% and a maximum formic acid yield of 92.6%. Even after five cycles, the catalytic activity remains above 91.7%, demonstrating high activity, high selectivity, and high stability. This provides a reliable new material approach for the efficient resource utilization of carbon dioxide. Attached Figure Description
[0012] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:
[0013] Figure 1 The carbon dioxide conversion rate and formic acid yield of the catalyst; Figure 2 This represents the catalyst's activity retention rate. Detailed Implementation
[0014] The following provides a detailed description of the embodiments of the present invention: These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and processes. However, the scope of protection of the present invention is not limited to the following embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions.
[0015] Example 1 A method for preparing a chromium-doped fullerene C20 catalyst and its application, comprising the following steps: Step 1: Disperse 0.5 mol of fullerene C20 in toluene, sonicate for 30 min to form a uniform suspension, then add 0.1 mol of chromium trichloride, and carry out the doping reaction at 60 °C for 6 h under nitrogen protection. After the reaction is completed, centrifuge to separate the product, wash with toluene, and dry at 60 °C for 20 h to obtain chromium-doped fullerene C20 catalyst.
[0016] Step 2: Add 10 mL of deionized water, 0.05 g of chromium-doped fullerene C20 catalyst, 0.05 mol of hydrogen, and 0.05 mol of carbon dioxide to the reaction vessel. Control the total pressure to 0.5 MPa and stir at 400 rpm at 80°C for 8 hours. After the reaction is complete, cool and collect the reaction product containing formic acid.
[0017] Example 2 A method for preparing a chromium-doped fullerene C20 catalyst and its application, comprising the following steps: Step 1: Disperse 1.5 mol of fullerene C20 in toluene, sonicate for 50 min to form a uniform suspension, then add 0.1 mol of chromium trichloride, and carry out the doping reaction at 100℃ for 2 h under nitrogen protection. After the reaction is completed, centrifuge to separate the product, wash with toluene, and dry at 90℃ for 10 h to obtain chromium-doped fullerene C20 catalyst.
[0018] Step 2: Add 20 mL of deionized water, 0.05 g of chromium-doped fullerene C20 catalyst, 0.15 mol of hydrogen, and 0.05 mol of carbon dioxide to the reaction vessel. Control the total pressure to 1.5 MPa and stir at 600 rpm at 120°C for 4 h. After the reaction is complete, cool and collect the reaction product containing formic acid.
[0019] Example 3 A method for preparing a chromium-doped fullerene C20 catalyst and its application, comprising the following steps: Step 1: Disperse 1.0 mol of fullerene C20 in toluene, sonicate for 40 min to form a uniform suspension, then add 0.1 mol of chromium trichloride, and carry out the doping reaction at 80 °C for 4 h under nitrogen protection. After the reaction is completed, centrifuge to separate the product, wash with toluene, and dry at 75 °C for 15 h to obtain chromium-doped fullerene C20 catalyst.
[0020] Step 2: Add 15 mL of deionized water, 0.05 g of chromium-doped fullerene C20 catalyst, 0.1 mol of hydrogen, and 0.05 mol of carbon dioxide to the reactor. Control the total pressure to 1.0 MPa and stir at 500 rpm at 100°C for 6 h. After the reaction is complete, cool and collect the reaction product containing formic acid.
[0021] Example 4 A method for preparing a chromium-doped fullerene C20 catalyst and its application, comprising the following steps: Step 1: Disperse 0.5 mol of fullerene C20 in toluene, sonicate for 50 min to form a uniform suspension, then add 0.1 mol of chromium trichloride, and carry out the doping reaction at 100℃ for 2 h under nitrogen protection. After the reaction is completed, centrifuge to separate the product, wash with toluene, and dry at 60℃ for 20 h to obtain chromium-doped fullerene C20 catalyst.
[0022] Step 2: Add 10 mL of deionized water, 0.05 g of chromium-doped fullerene C20 catalyst, 0.15 mol of hydrogen, and 0.05 mol of carbon dioxide to the reaction vessel. Control the total pressure to 1.5 MPa and stir at 400 rpm at 80°C for 8 h. After the reaction is complete, cool and collect the reaction product containing formic acid.
[0023] Comparative Example 1: The difference between this comparative example and Example 1 is that chromium trichloride is not added.
[0024] A method for preparing a chromium-doped fullerene C20 catalyst and its application includes the following steps: adding 10 mL of deionized water, 0.05 g of fullerene C20 catalyst, 0.05 mol of hydrogen, and 0.05 mol of carbon dioxide to a reaction vessel, controlling the total pressure to 0.5 MPa, stirring at 400 rpm and 80 °C for 8 h, and after the reaction is completed, cooling and collecting the reaction product containing formic acid.
[0025] Comparative Example 2: The difference between this comparative example and Example 1 is that activated carbon is used instead of fullerene C20.
[0026] A method for preparing a chromium-doped fullerene C20 catalyst and its application, comprising the following steps: Step 1: Disperse 0.5 mol of activated carbon in toluene, sonicate for 30 min to form a uniform suspension, then add 0.1 mol of chromium trichloride, and carry out the doping reaction at 60 °C for 6 h under nitrogen protection. After the reaction is completed, centrifuge to separate the product, wash with toluene, and dry at 60 °C for 20 h to obtain activated carbon-doped fullerene C20 catalyst.
[0027] Step 2: Add 10 mL of deionized water, 0.05 g of activated carbon-doped fullerene C20 catalyst, 0.05 mol of hydrogen, and 0.05 mol of carbon dioxide to the reaction vessel. Control the total pressure to 0.5 MPa and stir at 400 rpm at 80°C for 8 h. After the reaction is complete, cool and collect the reaction product containing formic acid.
[0028] Comparative Example 3: The difference between this comparative example and Example 1 is that no doping reaction is performed; fullerene C20 and chromium trichloride are only physically mixed.
[0029] A method for preparing a chromium-doped fullerene C20 catalyst and its application, comprising the following steps: Step 1: Disperse 0.5 mol of fullerene C20 in toluene, sonicate for 30 min to form a uniform suspension, then add 0.1 mol of chromium trichloride, mix well, let stand for 6 h, centrifuge to separate the product, wash with toluene, and dry at 60℃ for 20 h to obtain chromium-fullerene C20 catalyst.
[0030] Step 2: Add 10 mL of deionized water, 0.05 g of chromium-doped fullerene C20 catalyst, 0.05 mol of hydrogen, and 0.05 mol of carbon dioxide to the reaction vessel. Control the total pressure to 0.5 MPa and stir at 400 rpm at 80°C for 8 hours. After the reaction is complete, cool and collect the reaction product containing formic acid.
[0031] Performance testing 1. Carbon dioxide conversion rate Add 0.05 g of the catalyst to be tested and 10 mL of deionized water to the reactor. Evacuate the reactor using a vacuum pump. Record the initial number of moles of carbon dioxide added using a mass flow meter, denoted as n. 初始CO2 The reaction was carried out at 120℃ and 500 rpm for 6 hours with stirring. After the reaction was completed, a certain amount of tail gas was collected from the reactor, and the concentration of carbon dioxide in it was analyzed by gas chromatography. Based on the partial pressure of carbon dioxide concentration in the tail gas and the volume, pressure, and temperature of the reactor, the number of unreacted carbon dioxide moles (n) was calculated. 最终CO2 ).
[0032] Carbon dioxide conversion rate = [(initial CO2 moles - remaining CO2 moles) / initial CO2 moles] × 100%.
[0033] 2-Formic acid yield Add 0.05 g of the catalyst to be tested and 10 mL of deionized water to the reactor. Evacuate the reactor using a vacuum pump to eliminate air interference. Accurately record the initial number of moles of carbon dioxide added using a mass flow meter, denoted as n. 初始CO2 The reaction temperature was set at 120℃, the stirring rate at 500 rpm, and the reaction time at 6 h. The total system pressure was maintained between 0.5 and 1.0 MPa during the reaction. After the reaction, the reaction system was cooled to room temperature. The reaction solution was collected for subsequent formic acid content analysis. High-performance liquid chromatography (HPLC) or ion chromatography was used for quantitative analysis of formic acid in the reaction solution. The concentration of formic acid in the reaction solution (unit: mol / L) was calculated based on the peak area of formic acid using the standard curve method. The number of moles of formic acid produced was calculated based on the volume of the reaction solution and denoted as n. 甲酸 .
[0034] Formic acid selectivity = (number of moles of CO2 consumed to produce formic acid / total number of moles of CO2 consumed) × 100%, where the number of moles of CO2 consumed to produce formic acid = n 甲酸 The total number of CO2 moles consumed = n 初始CO2 -n 最终CO2 .
[0035] Formic acid yield = CO2 conversion rate × formic acid selectivity 3. Cyclic stability (activity retention after 5 cycles) S1. Add 0.05 g of the catalyst to be tested and 10 mL of deionized water to the reactor. Evacuate the reactor using a vacuum pump. Record the initial number of moles of carbon dioxide added using a mass flow meter, denoted as n. ¹ 初始CO2 The reaction was carried out at 120°C and 500 rpm for 6 hours. After the reaction was completed, the following operations were performed: a) The tail gas was collected from the reactor and the concentration of carbon dioxide was analyzed by gas chromatography. The number of unreacted carbon dioxide moles (n) was calculated. ¹ 最终CO2 b) Centrifuge the reaction solution, transfer the supernatant (containing formic acid product) for analysis, and retain the solid catalyst; c) Add fresh toluene to the remaining solid, ultrasonically wash for 5-10 min, then centrifuge and discard the supernatant. Repeat this step 2-3 times to remove organic matter and by-products adsorbed on the catalyst surface; d) Dry the washed solid catalyst under vacuum at 60°C for 2-4 h to obtain the recovered catalyst.
[0036] S2. Reload the recovered and dried catalyst (0.05 g by mass) from the first cycle back into the reactor. Add 10 mL of fresh deionized water. Repeat all the reaction and testing steps from the first cycle: evacuate, introduce the same molar amounts of CO2 and H2, react under the same conditions, measure the tail gas after the reaction, and recover the catalyst. Record the initial and final molar amounts of CO2 for each cycle, denoted as n. n 初始CO2 and n n 最终CO2 (n is the number of loops).
[0037] S3, Xn = (n n 初始CO2 - n n 最终CO2 ) / n n 初始CO2 ×100%, the activity retention rate after the 5th cycle = X5 / X1×100%, where X1 is the conversion rate of the 1st cycle and X5 is the conversion rate of the 5th cycle.
[0038] Table 1 Catalytic performance test data
[0039] As shown in Table 1, the chromium-doped fullerene C20 catalysts prepared in Examples 1–4 exhibited excellent catalytic performance in the hydrogenation of carbon dioxide, with formic acid yields all exceeding 85.8%, and the activity retention rate exceeding 91.7% after five cycles. This indicates that chromium, as the catalytic active center, forms a stable synergistic effect with fullerene C20. Fullerene C20 possesses a defined cage-like structure and unique electronic properties, which can effectively regulate the electron density of chromium species, enhancing its activation ability for CO2 and H2, thereby significantly improving catalytic efficiency and stability.
[0040] In contrast, Comparative Example 1, without the addition of chromium trichloride, produced a catalyst with extremely low carbon dioxide conversion (5.0%) and formic acid yield (3.0%) during the catalytic hydrogenation of carbon dioxide to formic acid. After five cycles, the activity retention rate was only 35.4%. This indicates that the catalytic activity of the fullerene C20 support itself is negligible. The active sites formed by the combination of chromium and C20 lead to extremely high carbon dioxide conversion and formic acid yield. Without chromium, the entire catalytic system is almost ineffective. Comparative Example 2 showed significantly lower carbon dioxide conversion and formic acid yield than Example 1, and poorer stability. This is because the activated carbon has an irregular structure and non-uniform electronic properties. Although it can support chromium and generate some catalytic activity, its performance is far inferior to the catalyst supported on fullerene C20. It lacks unique advantages in dispersing chromium, stabilizing active sites, and synergistic catalysis. Comparative Example 3 did not undergo a doping reaction; chromium trichloride was simply physically mixed to adhere to the C20 surface. There was only weak physical adsorption or van der Waals forces between the two, and chromium atoms could not enter the carbon cage of the fullerene C20 through chemical bonds. As a result, a more robust and electronically coupled integrated structure was not formed. Consequently, the prepared catalyst had significantly lower CO2 conversion rate (65.0%) and formic acid yield (55.3%) than all examples during the catalytic hydrogenation of carbon dioxide to formic acid, and its stability (activity retention rate of 75%) was inferior to that of the examples.
[0041] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A method for preparing a chromium-doped fullerene C20 catalyst, characterized in that, Includes the following steps: Fullerene C20 was dispersed in toluene and ultrasonically treated to form a uniform suspension. Chromium trichloride was then added, and the doping reaction was carried out under nitrogen protection. After the reaction was completed, the product was separated by centrifugation, washed with toluene, and dried to obtain the chromium-doped fullerene C20 catalyst.
2. The method for preparing the chromium-doped fullerene C20 catalyst according to claim 1, characterized in that, The ultrasonic treatment time is 30-50 minutes.
3. The method for preparing the chromium-doped fullerene C20 catalyst according to claim 1, characterized in that, The doping reaction is carried out at a temperature of 60-100℃ for 2-6 hours.
4. The method for preparing the chromium-doped fullerene C20 catalyst according to claim 1, characterized in that, The drying temperature is 60-90℃, and the time is 10-20 h.
5. The method for preparing the chromium-doped fullerene C20 catalyst according to claim 1, characterized in that, The molar ratio of fullerene C20 to chromium trichloride is (5-15):
1.
6. A chromium-doped fullerene C20 catalyst prepared by the preparation method according to any one of claims 1-5.
7. The application of the chromium-doped fullerene C20 catalyst of claim 6 in the catalytic hydrogenation of carbon dioxide to prepare formic acid.
8. A method for preparing formic acid by catalytic hydrogenation of carbon dioxide, characterized in that, The process includes the following steps: In a reaction vessel, deionized water, chromium-doped fullerene C20 catalyst, hydrogen, and carbon dioxide are added in a ratio of (200-400) mL: 1 g: (1-3) mol: 1 mol. The mixture is stirred and reacted. After the reaction is complete, the mixture is cooled and the reaction product containing formic acid is collected.
9. The method for preparing formic acid by catalytic carbon dioxide hydrogenation according to claim 8, characterized in that, The stirring reaction is carried out at a temperature of 80-120℃ for 4-8 hours, with a stirring rate of 400-600 rpm and a total pressure of 0.5-1.5 MPa.