A carbon-supported ruthenium-based catalyst, its preparation method and application

Abstract

This invention belongs to the field of organic chemical synthesis technology, specifically relating to a carbon-supported ruthenium-based catalyst, its preparation method, and its application. The carbon-supported ruthenium-based catalyst includes a support and an active component supported on the support. The support is microporous carbon prepared by sintering soluble sugars, and the active component is Ru. 3+ Ions, the Ru 3+ The ion mass is 1% to 3% of the support mass. The carbon-supported ruthenium-based catalyst of this invention exhibits high catalytic activity in the hydrogenation of carbon dioxide to formic acid, can be recycled multiple times, has stable activity, and operates under mild reaction conditions with a short reaction time, thus reducing the production cost of the hydrogenation of carbon dioxide to formic acid and facilitating its widespread application.

Description

Technical Field

[0001] This invention belongs to the field of organic chemical synthesis technology, specifically relating to a carbon-supported ruthenium-based catalyst, its preparation method, and its application. Background Technology

[0002] Currently, catalytic conversion of CO2 into smaller molecule products (such as syngas, methanol, dimethyl ether, formic acid, and low-carbon hydrocarbons) and other products with higher added value and greater market potential has become an important pathway for CO2 elimination and utilization. Formic acid, as a basic chemical raw material, is widely used in organic synthesis, printing and dyeing, leather goods, and food processing. The direct synthesis of formic acid from CO2 via hydrogenation is not only an atom-economical reaction but also requires relatively low energy consumption, making it an effective way to rationally utilize carbon dioxide and one of the methods for chemical fixation and conversion. Currently, the catalysts used for the hydrogenation of CO2 to formic acid and its derivatives are mainly homogeneous complex catalysts, both domestically and internationally. For example, Matthias Beller, Henrik Junge, and others from the Leibniz Institute for Catalysis in Germany reported a system for the reversible hydrogenation of CO2 to formic acid promoted by α-amino acids in Nature Energy, 2022, 7(5):438-447. This system uses Mn-pincer complexes as homogeneous catalysts, in which the total conversion number (TON) for the hydrogenation of CO2 to formic acid is 2,000,000. Although the homogeneous catalyst has high activity, the separation and recovery of the catalyst after the reaction is a difficult problem to overcome in industrial production, resulting in poor catalyst recycling. Summary of the Invention

[0003] To address the shortcomings of existing methods, this invention provides a carbon-supported ruthenium-based catalyst, its preparation method, and its applications.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] In a first aspect, the present invention provides a carbon-supported ruthenium-based catalyst, comprising a support and an active component supported on the support, wherein the support is microporous carbon prepared by sintering soluble sugars, and the active component is Ru. 3+ Ions, the Ru 3+ The ion mass is 1% to 3% of the carrier mass.

[0006] Preferably, the soluble sugar is one or more of d-glucose, pentose, and starch.

[0007] Secondly, the present invention provides a method for preparing a carbon-supported ruthenium-based catalyst, comprising the following steps:

[0008] Soluble sugars were mixed with ZnCl2 and placed in a tube furnace for calcination under a nitrogen atmosphere. After grinding, washing, and drying, microporous carbon was obtained. Then, solvent, RuCl3·3H2O, and the microporous carbon were placed in a beaker and stirred at room temperature. After washing and drying, the final product was obtained.

[0009] Preferably, the mass ratio of the soluble sugar to ZnCl2 is 1:2 to 4.

[0010] Preferably, the calcination conditions are: heating to 700℃~1100℃ at a heating rate of 1°~5° / min and calcining for 1~3 hours.

[0011] Preferably, the ratio of RuCl3·3H2O, microporous carbon, and solvent is 0.5–1.6 mg: 15–25 mg: 5–10 mL.

[0012] Thirdly, the present invention provides the application of a carbon-supported ruthenium-based catalyst in the catalytic hydrogenation of carbon dioxide to formic acid.

[0013] Preferably, the application includes: loading a carbon-supported ruthenium-based catalyst, deionized water and triethylamine into a high-pressure reactor, purging the high-pressure reactor with CO2 gas to replace the air inside the reactor, sequentially introducing liquefied CO2 and H2 into the high-pressure reactor, performing a hydrogenation reaction under stirring conditions, and cooling and depressurizing after the reaction is completed.

[0014] Preferably, the ratio of triethylamine, deionized water, and carbon-supported ruthenium-based catalyst is 1-3 mL: 5-10 mL: 5-20 mg.

[0015] Preferably, the hydrogenation reaction temperature is 100–120°C, the pressure is 3–6 MPa, and the reaction time is 1–12 h.

[0016] The positive and beneficial effects of this invention are as follows:

[0017] 1. The microporous carbon-supported Ru in this invention 3+ The catalyst is used in the hydrogenation of carbon dioxide to formic acid reaction. The microporous carbon is prepared through a sintering process of soluble sugars, forming a rich microporous structure that facilitates the loading of large amounts of Ru. 3+ The catalyst of this invention is simple, easy to prepare, and inexpensive. It exhibits high catalytic activity and excellent cycle stability, achieving a cycle performance of up to 95% after five repeated reactions. It can be reused multiple times while maintaining stable activity. Furthermore, the catalytic hydrogenation of carbon dioxide to formic acid is carried out under mild reaction conditions and with a short reaction time, significantly reducing production costs and demonstrating promising prospects for widespread application. Attached Figure Description

[0018] Figure 1These are SEM images of the carbon-supported ruthenium-based catalysts prepared in Examples 1-5 of this invention, with Figure af corresponding to Examples 1-5;

[0019] Figure 2 The N2 adsorption-desorption isotherms (a) and pore size distribution (b) of the carbon-supported ruthenium-based catalysts prepared in Examples 1-5 of this invention are shown.

[0020] Figure 3 This is a graph showing the cycling data of the carbon-supported ruthenium-based catalyst prepared in Example 4 of the present invention. Detailed Implementation

[0021] The present invention will be further described below with reference to some specific embodiments.

[0022] Example 1

[0023] A method for preparing a carbon-supported ruthenium-based catalyst includes the following steps:

[0024] S1. Soluble sugar d-glucose and ZnCl2 were physically mixed in a mass ratio of 1:3 and placed in a tube furnace. Under a nitrogen atmosphere, the temperature was increased to 700℃ for 2 hours at a heating rate of 3° / min. After calcination, the sample was a black block solid. It was then ground, filtered with deionized water, washed and dried to obtain a microporous carbon support.

[0025] S2. Weigh 10.6 mg of RuCl3·3H2O and 200 mg of microporous carbon support and add them to a beaker containing 50 mL of methanol. Stir at room temperature for 1 h, then remove the weakly bound Ru by filtration with deionized water. 3+ After drying at 60℃ for 24 hours, carbon-supported ruthenium-based catalyst was obtained.

[0026] Example 2

[0027] A method for preparing a carbon-supported ruthenium-based catalyst includes the following steps:

[0028] S1. Soluble sugar d-glucose and ZnCl2 were physically mixed in a mass ratio of 1:3 and placed in a tube furnace. Under a nitrogen atmosphere, the temperature was increased to 800℃ for 2 hours at a heating rate of 3° / min. After calcination, the sample was a black solid block. It was then ground, filtered with deionized water, washed and dried to obtain a microporous carbon support.

[0029] S2. Weigh 10.6 mg of RuCl3·3H2O and 200 mg of microporous carbon support and add them to a beaker containing 50 mL of methanol. Stir at room temperature for 1 h, then remove the weakly bound Ru by filtration with deionized water. 3+ After drying at 60℃ for 24 hours, carbon-supported ruthenium-based catalyst was obtained.

[0030] Example 3

[0031] A method for preparing a carbon-supported ruthenium-based catalyst includes the following steps:

[0032] S1. Soluble sugar d-glucose and ZnCl2 were physically mixed in a mass ratio of 1:3 and placed in a tube furnace. Under a nitrogen atmosphere, the temperature was raised to 900℃ for 2 hours at a heating rate of 3° / min. After calcination, the sample was a black block solid. It was then ground, filtered with deionized water, washed and dried to obtain a microporous carbon support.

[0033] S2. Weigh 10.6 mg of RuCl3·3H2O and 200 mg of microporous carbon support and add them to a beaker containing 50 mL of methanol. Stir at room temperature for 1 h, then remove the weakly bound Ru by filtration with deionized water. 3+ After drying at 60℃ for 24 hours, carbon-supported ruthenium-based catalyst was obtained.

[0034] Example 4

[0035] A method for preparing a carbon-supported ruthenium-based catalyst includes the following steps:

[0036] S1. Soluble sugar d-glucose and ZnCl2 were physically mixed in a mass ratio of 1:3 and placed in a tube furnace. Under a nitrogen atmosphere, the temperature was increased to 1000℃ for 2 hours at a heating rate of 3° / min. After calcination, the sample was a black block solid. It was then ground, filtered with deionized water, washed and dried to obtain a microporous carbon support.

[0037] S2. Weigh 10.6 mg of RuCl3·3H2O and 200 mg of microporous carbon support and add them to a beaker containing 50 mL of methanol. Stir at room temperature for 1 h, then remove the weakly bound Ru by filtration with deionized water. 3+ After drying at 60℃ for 24 hours, carbon-supported ruthenium-based catalyst was obtained.

[0038] Example 5

[0039] A method for preparing a carbon-supported ruthenium-based catalyst includes the following steps:

[0040] S1. Soluble sugar d-glucose and ZnCl2 were physically mixed in a mass ratio of 1:3 and placed in a tube furnace. Under a nitrogen atmosphere, the temperature was raised to 1100℃ for 2 hours at a heating rate of 3° / min. The calcined sample was a black block solid. After grinding, it was filtered with deionized water, washed and dried to obtain a microporous carbon support.

[0041] S2. Weigh 10.6 mg of RuCl3·3H2O and 200 mg of microporous carbon support and add them to a beaker containing 50 mL of methanol. Stir at room temperature for 1 h, then remove the weakly bound Ru by filtration with deionized water. 3+ After drying at 60℃ for 24 hours, carbon-supported ruthenium-based catalyst was obtained.

[0042] Example 6

[0043] A method for preparing a carbon-supported ruthenium-based catalyst includes the following steps:

[0044] S1. Soluble sugar d-glucose and ZnCl2 were physically mixed in a mass ratio of 1:3 and placed in a tube furnace. Under a nitrogen atmosphere, the temperature was increased to 1000℃ for 2 hours at a heating rate of 3° / min. After calcination, the sample was a black block solid. It was then ground, filtered with deionized water, washed and dried to obtain a microporous carbon support.

[0045] S2. Weigh 5.3 mg of RuCl3·3H2O and 200 mg of microporous carbon support and add them to a beaker containing 50 mL of methanol. Stir at room temperature for 1 h, then remove the weakly bound Ru by filtration with deionized water. 3+ After drying at 60℃ for 24 hours, carbon-supported ruthenium-based catalyst was obtained.

[0046] Example 7

[0047] A method for preparing a carbon-supported ruthenium-based catalyst includes the following steps:

[0048] S1. Soluble sugar d-glucose and ZnCl2 were physically mixed in a mass ratio of 1:3 and placed in a tube furnace. Under a nitrogen atmosphere, the temperature was increased to 1000℃ for 2 hours at a heating rate of 3° / min. After calcination, the sample was a black block solid. It was then ground, filtered with deionized water, washed and dried to obtain a microporous carbon support.

[0049] S2. Weigh 15.9 mg of RuCl3·3H2O and 200 mg of microporous carbon support and add them to a beaker containing 50 mL of methanol. Stir at room temperature for 1 h, then remove the weakly bound Ru by filtration with deionized water. 3+ After drying at 60℃ for 24 hours, carbon-supported ruthenium-based catalyst was obtained.

[0050] Example 8

[0051] A method for preparing a carbon-supported ruthenium-based catalyst includes the following steps:

[0052] S1. Soluble sugar d-glucose and ZnCl2 were physically mixed in a mass ratio of 1:2 and placed in a tube furnace. Under a nitrogen atmosphere, the temperature was increased to 1000℃ for 2 hours at a heating rate of 3° / min. The calcined sample was a black block solid. After grinding, it was filtered with deionized water, washed and dried to obtain a microporous carbon support.

[0053] S2. Weigh 10.6 mg of RuCl3·3H2O and 200 mg of microporous carbon support and add them to a beaker containing 50 mL of methanol. Stir at room temperature for 1 h, then remove the weakly bound Ru by filtration with deionized water. 3+ After drying at 60℃ for 24 hours, carbon-supported ruthenium-based catalyst was obtained.

[0054] Example 9

[0055] A method for preparing a carbon-supported ruthenium-based catalyst includes the following steps:

[0056] S1, soluble sugar d-glucose and ZnCl2 were physically mixed in a mass ratio of 1:4 and placed in a tube furnace. Under a nitrogen atmosphere, the temperature was raised to 1000℃ for 2 hours at a heating rate of 3° / min. The calcined sample was a black solid block. After grinding, it was filtered with deionized water, washed and dried to obtain a microporous carbon support.

[0057] S2. Weigh 10.6 mg of RuCl3·3H2O and 200 mg of microporous carbon support and add them to a beaker containing 50 mL of methanol. Stir at room temperature for 1 h, then remove the weakly bound Ru by filtration with deionized water. 3+ After drying at 60℃ for 24 hours, carbon-supported ruthenium-based catalyst was obtained.

[0058] Example 10

[0059] A method for preparing a carbon-supported ruthenium-based catalyst includes the following steps:

[0060] S1. Soluble sugar d-glucose and ZnCl2 were physically mixed in a mass ratio of 1:3 and placed in a tube furnace. Under a nitrogen atmosphere, the temperature was increased to 1000℃ for 2 hours at a heating rate of 1° / min. The calcined sample was a black block solid. After grinding, it was filtered with deionized water, washed and dried to obtain a microporous carbon support.

[0061] S2. Weigh 10.6 mg of RuCl3·3H2O and 200 mg of microporous carbon support and add them to a beaker containing 50 mL of methanol. Stir at room temperature for 1 h, then remove the weakly bound Ru by filtration with deionized water. 3+ After drying at 60℃ for 24 hours, carbon-supported ruthenium-based catalyst was obtained.

[0062] Example 11

[0063] A method for preparing a carbon-supported ruthenium-based catalyst includes the following steps:

[0064] S1. Soluble sugars d-glucose and ZnCl2 were physically mixed in a mass ratio of 1:3 and placed in a tube furnace. Under a nitrogen atmosphere, the temperature was increased to 1000℃ for 2 hours at a heating rate of 5° / min. The calcined sample was a black solid block. After grinding, it was filtered with deionized water, washed and dried to obtain a microporous carbon support.

[0065] S2. Weigh 10.6 mg of RuCl3·3H2O and 200 mg of microporous carbon support and add them to a beaker containing 50 mL of methanol. Stir at room temperature for 1 h, then remove the weakly bound Ru by filtration with deionized water. 3+ After drying at 60℃ for 24 hours, carbon-supported ruthenium-based catalyst was obtained.

[0066] Comparative Example 1

[0067] A method for preparing a carbon-supported ruthenium-based catalyst includes the following steps:

[0068] 10.6 mg RuCl3·3H2O and 200 mg commercial carbon nanotube (CNT) support were weighed and added to a beaker containing 50 mL of methanol. The mixture was stirred at room temperature for 1 h, and then the weakly bound Ru was removed by centrifugation and washing. 3+ Then, after drying at 60°C for 24 hours, a carbon-supported ruthenium-based catalyst Ru / CNT with a Ru loading of 2% was obtained.

[0069] Comparative Example 2

[0070] A method for preparing a carbon-supported ruthenium-based catalyst includes the following steps:

[0071] Weigh 10.6 mg RuCl3·3H2O and 200 mg commercial mesoporous carbon MC and add them to a beaker containing 50 mL of methanol. Stir at room temperature for 1 h, then remove weakly bound Ru by centrifugation and washing. 3+ Then, after drying at 60°C for 24 hours, a carbon-supported ruthenium-based catalyst Ru / MC with a Ru loading of 2% was obtained.

[0072] Comparative Example 3

[0073] A method for preparing a carbon-supported ruthenium-based catalyst includes the following steps:

[0074] Weigh 10.6 mg RuCl3·3H2O and 200 mg commercial carbon black MA carrier and add them to a beaker containing 50 mL of methanol. Stir at room temperature for 1 h, then remove weakly bound Ru by centrifugation and washing. 3+After drying at 60℃ for 24 hours, a carbon-supported ruthenium-based catalyst Ru / MA with a Ru loading of 2% was obtained.

[0075] SEM images of Ru / C prepared at different calcination temperatures in Examples 1-5 are shown below. Figure 1 The nitrogen adsorption-desorption curves and pore size distribution diagrams are shown in [reference 1]. Figure 2 Table 1 shows the BET test results of the specific surface area of ​​the carbon-supported ruthenium-based catalysts obtained in Examples 1-11 and Comparative Examples 1-3, as well as in Examples 2b and 2b.

[0076] Depend on Figure 1 As can be seen, SEM tests were performed on catalysts prepared at different calcination temperatures. The catalyst of the present invention exhibits a small blocky shape, which allows Ru to be fully dispersed.

[0077] Depend on Figure 2 As shown in Table 1, BET tests were performed on catalysts prepared at different calcination temperatures, and nitrogen adsorption-desorption curves and pore size distribution diagrams were obtained. The catalysts of this invention are mainly microporous. The specific surface area of ​​the catalyst prepared in Example 4 is significantly larger than that of the catalysts in other examples and the comparative catalyst, proving that it has the most micropores.

[0078] The application of the carbon-supported ruthenium-based catalysts prepared in Examples 1-11 and Comparative Examples 1-3 to the hydrogenation of carbon dioxide to formic acid includes the following steps:

[0079] A 50 mL high-pressure reactor was used. 5 mg of carbon-supported ruthenium-based catalyst, 6 mL of deionized water, and 1.2 mL of triethylamine were added. The mixture was gently shaken to ensure homogeneity of the reagents and catalyst. The reactor was then purged with CO2 gas to replace the air inside. Liquefied CO2 was introduced into the reactor until the pressure reached 3 MPa. After the pressure stabilized, H2 was introduced into the reactor to bring the total pressure to 6 MPa. The reactor was then heated to a reaction temperature of 120 °C with a stirring rate of 800 r / min. After 12 h of reaction, the reactor was cooled and depressurized. The reactor was then rapidly cooled, and the liquid product containing the suspended catalyst was collected and filtered through a 0.2 μm filter. Formate concentration was determined using a high-performance liquid chromatography (HPLC) system (YL 9100Plus, YL Instruments Co., Ltd.) equipped with an ultraviolet detector and an Aminex HPX-87H column. The operating temperature was 30℃, and 0.6 mL of 5 mM H2SO4 solution was used as the eluent. The test results are shown in Table 1.

[0080] The catalyst activity evaluation index is calculated using the conversion number (TON) of the target product formate, as follows:

[0081] TON = N HCOO- / N Ru

[0082] N HCOO - : Amount of the target product formate produced in the reaction (mol); N Ru The active component Ru used in the reaction 3+ The amount of substance (mol) of an ion;

[0083] Formate concentration (mol / L) = N HCOO - / V 产物 .

[0084] Table 1 Results of the reaction for producing formic acid by hydrogenation of carbon dioxide.

[0085]

[0086]

[0087] As shown in Table 1, based on the test results of Examples 1-5, the optimal calcination temperature of the present invention is 1000℃ as in Example 4; based on the test results of Examples 4 and 6-7, the optimal Ru... 3+ The ion mass is 2% of the carrier mass; the test results of Examples 4, 8-9 show that the optimal mass ratio of d-glucose to ZnCl2 in this invention is 1:3; the test results of Examples 4, 10-11 show that the optimal heating rate in this invention is 3°C / min. The carbon-supported ruthenium-based catalyst of this invention has a better catalytic effect than comparative Examples 1-3, and the conversion number of formate in this invention can reach as high as 10696.

[0088] Cyclic stability tests were conducted using the carbon-supported ruthenium-based catalyst prepared in Example 4. The procedure was as follows: 20 mg of the carbon-supported ruthenium-based catalyst from Example 4 was weighed into a 50 mL high-pressure reactor. 6 mL of deionized water and 1.2 mL of triethylamine were then added to the reactor and gently shaken to ensure uniform mixing of the reagents and catalyst. The reactor was then purged with CO2 gas to replace the air inside. Liquefied CO2 was introduced into the reactor until the pressure reached 3 MPa. After the pressure stabilized, H2 was introduced into the reactor again to bring the total pressure to 6 MPa. The reactor was then heated to a reaction temperature of 120 °C with a stirring rate of 800 r / min. After reacting for 1 hour, the reactor was cooled and depressurized. After the reaction, the reactor was rapidly cooled, and the liquid product containing the suspended catalyst was collected and filtered through a 0.2 μm filter. After each run, the catalyst was separated by filtration, washed with 50 mL each of water and acetone, and vacuum-dried at 60°C before the next run. The catalyst stability was tested over five consecutive runs. The collected liquid product was analyzed for formate concentration using a high-performance liquid chromatography (HPLC) system (YL 9100Plus, YL Instruments Co., Ltd.) equipped with a UV detector and an Aminex HPX-87H column. The operating temperature was 30°C, and 0.6 mL of 5 mM H₂SO₄ solution was used as the eluent. The test results are shown in Table 2. Figure 3 .

[0089] Table 2. Cyclic stability test results of carbon-supported ruthenium-based catalysts

[0090] Loop count <![CDATA[Ru 3+ Ion loading % Formate concentration (mol / L) TON 1 2 0.73 1778 2 2 0.73 1763 3 2 0.71 1733 4 2 0.71 1715 5 2 0.70 1697

[0091] As shown in Table 2, the carbon-supported ruthenium-based catalyst prepared in Example 4 was applied to the carbon dioxide hydrogenation to formic acid reaction. During five consecutive 1-hour runs, the catalyst activity remained very stable. Figure 3 As can be seen from the data of the fifth conversion, the reaction activity is still as high as 95% of that of the first reaction, which proves the excellent ability of the carbon-supported ruthenium-based catalyst of the present invention in terms of cycle stability.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention, as long as they do not depart from the spirit and scope of the technical solutions of the present invention, should be covered within the scope of the claims of the present invention.

Claims

1. A carbon-supported ruthenium-based catalyst, characterized in that, comprising a support and an active component supported on the support, the support being a microporous carbon sintered from d-glucose, the active component being Ru 3+ ions, the Ru 3+ ions having a mass of 1% to 3% of the mass of the support; The preparation method of the carbon-supported ruthenium-based catalyst includes the following steps: d-glucose was mixed with ZnCl2 and placed in a tube furnace for calcination under a nitrogen atmosphere. After grinding, washing and drying, microporous carbon was obtained. Then, solvent, RuCl3·3H2O and the above microporous carbon were placed in a beaker and stirred at room temperature. After washing and drying, the final product was obtained.

2. The method for preparing the carbon-supported ruthenium-based catalyst according to claim 1, characterized in that, The mass ratio of d-glucose to ZnCl2 is 1:2~4.

3. The method for preparing the carbon-supported ruthenium-based catalyst according to claim 1, characterized in that, The calcination conditions are as follows: heating to 700℃~1100℃ at a heating rate of 1℃~5℃ / min and calcining for 1~3 hours.

4. The method for preparing the carbon-supported ruthenium-based catalyst according to claim 1, characterized in that, The ratio of RuCl3·3H2O, microporous carbon, and solvent is 0.5~1.6 mg: 15~25 mg: 5~10 mL.

5. The application of the carbon-supported ruthenium-based catalyst according to claim 1 in the catalytic hydrogenation of carbon dioxide to formic acid.

6. The application according to claim 5, characterized in that, include: A carbon-supported ruthenium-based catalyst, deionized water, and triethylamine were loaded into a high-pressure reactor. The reactor was then purged with CO2 gas to replace the air inside. Liquefied CO2 and H2 were sequentially introduced into the reactor, and hydrogenation was carried out under stirring. After the reaction was completed, the reactor was cooled and depressurized.

7. The application according to claim 6, characterized in that, The ratio of triethylamine, deionized water, and carbon-supported ruthenium-based catalyst is 1~3 mL: 5~10 mL: 5~20 mg.

8. The application according to claim 7, characterized in that, The hydrogenation reaction temperature is 100~120 ℃, the pressure is 3~6 MPa, and the reaction time is 1~12 h.

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