Non-noble metal (at) MOF topological regulation catalyst synthesized by interface method and preparation method and application thereof

Abstract

The invention discloses a non-noble metal (at) MOF topological regulation catalyst synthesized by an interface method and a preparation method and application thereof, and belongs to the field of catalysis. Preparing a metal salt aqueous solution and a solution A; preparing a functionalized ligand organic solution and a solution B; performing room-temperature interface reaction on the solution A and the solution B to obtain a non-noble metal (at) MOF topological regulation catalyst precursor; and washing and drying the precursor to obtain the non-noble metal (at) MOF topological regulation catalyst which is used for preparing a C2 product by electrocatalytic CO2 reduction. The Faraday efficiency of the C2 product reaches 93.1%, stable operation is carried out for 10 hours under the current density of 502.7 mA.cm <-2 >, and the method has the advantages of being low in price, high in C2 product selectivity and excellent in stability.

Description

Technical Field

[0001] This invention belongs to the field of catalytic synthesis, specifically relating to a one-step interfacial synthesis of non-noble metal @MOF topology-controlled catalysts at room temperature and its preparation method and route. Specifically, the catalytic reaction system involved is the preparation of C2 products (such as ethylene, ethanol, etc.) in the electrocatalytic carbon dioxide reduction reaction (CO2RR). Background Technology

[0002] The increasingly severe global carbon emission problem has triggered serious environmental pressure and carbon resource waste. Electrocatalytic CO2 reduction (CO2RR), which converts carbon dioxide into high-value-added C2 products (such as C2H4 and C2H5OH), can achieve efficient utilization of carbon resources and carbon-negative development. In recent years, various CO2 conversion technologies, including thermocatalytic reduction, photocatalytic reduction, and electrocatalytic reduction, have been widely designed and developed. Among them, electrocatalytic CO2RR has become one of the most promising methods for industrial application due to its mild reaction conditions and easily tunable product selectivity. The core of electrocatalytic CO2RR is the coupling reaction between CO intermediate formation and C2C. Currently, metal-organic frameworks (MOFs) have become the mainstream candidate catalysts for CO2RR due to their ultra-high specific surface area and tunable active sites. However, traditional MOF catalysts have significant drawbacks: low C2 product selectivity, poor long-term stability, and the preparation process often requires high temperature, high pressure, or complex post-processing steps, limiting practical applications.

[0003] Non-noble metal@MOF topology-regulated materials, as a novel type of catalytic material, are two-dimensional nanostructures formed by the interfacial self-assembly of functionalized ligands and non-noble metals. Compared with traditional catalysts, these materials possess uniquely regulated topologies, high exposure of active sites, and short mass transfer pathways. Furthermore, they combine the low-cost advantages of non-noble metals with the structural tunability of MOFs, significantly improving C2 selectivity and stability. These characteristics make non-noble metal@MOF topology-regulated materials highly promising for applications in electrochemical catalysis; however, research on using these materials as catalysts for CO2RR to C2 products remains scarce. Summary of the Invention

[0004] To address the problems of existing technologies, one of the objectives of this invention is to provide a simple method for preparing a non-noble metal@MOF topology-controlled catalyst. This catalyst can be used for the electrocatalytic reduction of CO2 to prepare C2 products, and it features high activity, excellent stability, mild reaction conditions, and versatility.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for preparing a non-noble metal@MOF topology-controlled catalyst, the method comprising the following steps:

[0007] (1) Prepare an aqueous solution of a metal salt, solution A;

[0008] (2) Prepare functionalized ligand organic solution, solution B;

[0009] (3) Solution A and solution B were subjected to an interfacial reaction at room temperature to obtain a non-noble metal@MOF topology-controlled catalyst precursor;

[0010] (4) The precursor is washed and dried to obtain a non-precious metal@MOF topology-controlled catalyst, which is used for electrocatalytic CO2 reduction to prepare C2 products.

[0011] Preferably, the method for preparing the metal salt aqueous solution in step (1) includes the following steps:

[0012] Add the non-precious metal salt and stabilizer to the aqueous solvent and ultrasonically disperse until completely dissolved; maintain the natural dispersion state of the solution.

[0013] Preferably, the non-precious metal salt is selected from any one of copper acetate (Cu(Ac)2·2H2O), cobalt acetate (Co(Ac)2·4H2O), nickel acetate (Ni(Ac)2·4H2O), copper chloride (CuCl2·2H2O), and cobalt chloride (CoCl2·6H2O).

[0014] Preferably, the stabilizer is polyvinylpyrrolidone (PVP) K30, and the mass ratio of the non-precious metal salt to the stabilizer is 15:1 to 45:1.

[0015] Preferably, the solvent is deionized water, and the concentration of the non-precious metal salt is 50-100 mg / mL. Each 4-8 mL of solvent corresponds to 10.0-30.0 mg of stabilizer.

[0016] Preferably, the preparation method of the functionalized ligand solution in step (2) includes: dispersing the functionalized dicarboxylic acid ligand in a mixed solvent and ultrasonically dispersing it for 5 to 10 minutes until it is completely dissolved.

[0017] Preferably, the functionalized dicarboxylic acid ligand is selected from any one of 2-methylterephthalic acid, 2,5-dimethylterephthalic acid, and terephthalic acid.

[0018] Preferably, the mixed solvent is a mixture of N,N-dimethylacetamide (DMAc) and ethyl acetate in a volume ratio of 1:1, and each 8-16 mL of the mixed solvent corresponds to 20.0-35.0 mg of functionalized dicarboxylic acid ligand.

[0019] Preferably, the conditions for the room temperature interfacial reaction in step (3) are as follows: solution A is slowly added dropwise to solution B, and the reaction is allowed to proceed at room temperature (25°C) for 8-16 hours without additional stirring or heating. Generally, 4-8 mL of solution A corresponds to 8-16 mL of solution B.

[0020] Preferably, the washing solvent in step (4) includes N,N-dimethylacetamide and anhydrous ethanol, and each is washed 2 to 3 times in sequence; the drying method is freeze drying, and the drying time is 10 to 14 hours.

[0021] The second objective of this invention is to provide a non-noble metal @MOF topology-controlled catalyst as described above, which is prepared by the method described above.

[0022] The third objective of this invention is to provide an application of the non-noble metal @MOF topology-controlled catalyst as described above, which is used in the electrocatalytic CO2RR reduction reaction to prepare C2 products (such as ethylene, ethanol, etc.).

[0023] The electrocatalytic reaction system described above is a flow electrolyzer using a three-electrode system. The working electrode is a catalyst-supported gas diffusion electrode, the reference electrode is Ag / AgCl, and the counter electrode is nickel foam. The electrolyte is a 0.5–1.5 M KOH solution, which needs to be saturated with CO2 gas for 20–40 minutes before use, and CO2 is continuously introduced during the reaction. The reaction conditions are: reaction temperature at room temperature (20–25 °C), applied potential range of -1.4 V to -1.9 V (vs. RHE), and CO2 gas flow rate of 20–30 mL / min. -1 The electrolyte circulation flow rate is 2.5~4.0 mL·min. -1 .

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The preparation method of the non-noble metal @MOF topology-controlled catalyst synthesized in this invention is simple, the raw materials are readily available and inexpensive, and the catalyst has good synthesis and reproducibility, making it easy to achieve industrial scale-up;

[0026] (2) The non-noble metal@MOF topology-controlled catalyst described in this invention has excellent catalytic activity in the electrocatalytic CO2 reduction to C2 product reaction, high C2 product selectivity, and the highest Faraday efficiency can reach 93.1%, while the hydrogen evolution reaction is significantly inhibited.

[0027] (3) The non-noble metal@MOF topology-controlled catalyst of the present invention has excellent stability, and the corresponding current density can be 200-500 mA / cm. 2 And at high current density (500 mA / cm²) 2After running continuously for 10 hours, the catalyst performance did not show a significant decline. Attached Figure Description

[0028] Figure 1 This is a comparison chart of the CO2RR Faradaic efficiencies of the Cu-tp, Cu-Me-tp, and Cu-Me2-tp catalysts in Examples 1-3 of this invention at different potentials;

[0029] Figure 2 The Cu-Me-tp catalyst of Example 2 of this invention was tested at 502.7 mA·cm⁻¹. -2 Stability test results at current density;

[0030] Figure 3 This is an elemental distribution diagram of the Cu-Me-tp catalyst after electrolysis in Example 2 of the present invention. Detailed Implementation

[0031] The embodiments of the present invention will be described in detail below with reference to examples. Those skilled in the art will understand that the following embodiments are merely preferred embodiments of the present invention and are only intended to help better understand the present invention, and should not be regarded as specific limitations on the present invention.

[0032] Unless otherwise specified, the experimental methods used in the following examples are conventional methods; and the experimental materials used, unless otherwise specified, were purchased from conventional biochemical reagent manufacturers.

[0033] Example 1

[0034] Preparation of Solution A: Add 421.3 mg of copper acetate (Cu(Ac)2・2H2O) and 20.0 mg of polyvinylpyrrolidone (PVP) K30 to 6 mL of deionized water, and sonicate for 10 minutes to obtain a clear and transparent blue solution;

[0035] Solution B preparation: Disperse 24.9 mg of terephthalic acid (unsubstituted ligand) in a mixed solvent of 6 mL N,N-dimethylacetamide (DMAc) and 6 mL ethyl acetate, and sonicate for 5 minutes until the ligand is completely dissolved;

[0036] Interfacial reaction: Solution A was slowly added dropwise to solution B, and the reaction was allowed to proceed at room temperature (25°C) for 12 hours.

[0037] Post-processing: The reaction product was washed three times with DMAc and three times with anhydrous ethanol, and then freeze-dried for 12 hours to obtain the conventional symmetric topological MOF catalyst (Cu-tp).

[0038] Test method for CO2RR performance of catalyst Cu-tp:

[0039] A three-electrode system was used in a flow electrolyzer. The working electrode was a gas diffusion electrode (GDE) supported on a Cu-tp catalyst, the reference electrode was Ag / AgCl (saturated KCl), and the counter electrode was nickel foam. The electrolyte was a 1.0 M KOH solution, saturated with CO2 gas for 30 minutes before use. CO2 was continuously introduced during the reaction at a flow rate of 25 mL / min. -1 The electrolyte circulation rate is 3.3 mL·min. -1 .

[0040] Performance was tested at -1.7 V (vs. RHE) potential using gas chromatography and... 1 Quantitative analysis of the products was performed using 1H NMR spectroscopy. The results showed a Faradaic efficiency of 24.4% for the hydrogen evolution reaction (HER) and 53.0% for the C2 products (ethylene, ethanol, etc.), corresponding to a current density of 220.0 mA·cm⁻¹. -2 .

[0041] Example 2

[0042] Preparation of Solution A: Add 421.3 mg of copper acetate (Cu(Ac)2・2H2O) and 20.0 mg of polyvinylpyrrolidone (PVP) K30 to 6 mL of deionized water, and sonicate for 10 minutes to obtain a clear and transparent blue solution;

[0043] Solution B preparation: Disperse 27.2 mg of 2-methylterephthalic acid (functionalized ligand) in a mixed solvent of 6 mL N,N-dimethylacetamide (DMAc) and 6 mL ethyl acetate, and sonicate for 5 minutes until the ligand is completely dissolved;

[0044] Interfacial reaction: Solution A was slowly added dropwise to solution B, and the reaction was allowed to proceed at room temperature (25°C) for 12 hours.

[0045] Post-processing: The reaction product was washed three times with DMAc and three times with anhydrous ethanol, and then freeze-dried for 12 hours to obtain a non-noble metal@MOF topology-controlled catalyst (Cu-Me-tp).

[0046] Test method for CO2RR performance of catalyst Cu-Me-tp:

[0047] A three-electrode system was used in a flow electrolyzer. The working electrode was a gas diffusion electrode (GDE) supported on a Cu-Me-tp catalyst, the reference electrode was Ag / AgCl (saturated KCl), and the counter electrode was nickel foam. The electrolyte was a 1.0 M KOH solution, saturated with CO2 gas for 30 minutes before use. CO2 was continuously introduced during the reaction at a flow rate of 25 mL / min. -1The electrolyte circulation rate is 3.3 mL·min. -1 .

[0048] Performance was tested at -1.7 V (vs. RHE) potential using gas chromatography and... 1 Quantitative analysis of the products was performed using 1H NMR spectroscopy. The results showed that the Faradaic efficiency of the hydrogen evolution reaction (HER) was only 4.5%, while the Faradaic efficiency of the C2 products (ethylene, ethanol, etc.) was as high as 93.1%, corresponding to a current density of 502.7 mA·cm⁻¹. -2 ; and at 502.7 mA·cm -2 After 10 hours of continuous operation at current density, the Faraday efficiency of the C2 product remained above 80%, the voltage fluctuation was less than 5%, and there was no obvious catalyst aggregation.

[0049] Example 3

[0050] Preparation of Solution A: Add 421.3 mg of copper acetate (Cu(Ac)2・2H2O) and 20.0 mg of polyvinylpyrrolidone (PVP) K30 to 6 mL of deionized water, and sonicate for 10 minutes to obtain a clear and transparent blue solution;

[0051] Solution B preparation: Disperse 29.1 mg of 2,5-dimethylterephthalic acid (disubstituted ligand) in a mixed solvent of 6 mL N,N-dimethylacetamide (DMAc) and 6 mL ethyl acetate, and sonicate for 5 minutes until the ligand is completely dissolved;

[0052] Interfacial reaction: Solution A was slowly added dropwise to solution B, and the reaction was allowed to proceed at room temperature (25°C) for 12 hours.

[0053] Post-processing: The reaction product was washed three times with DMAc and three times with anhydrous ethanol, and then freeze-dried for 12 hours to obtain a symmetric topologically substituted MOF catalyst (Cu-Me2-tp).

[0054] Test method for CO2RR performance of catalyst Cu-Me2-tp:

[0055] A three-electrode system was used in a flow electrolyzer. The working electrode was a gas diffusion electrode (GDE) supported on Cu-Me2-tp catalyst, the reference electrode was Ag / AgCl (saturated KCl), and the counter electrode was nickel foam. The electrolyte was a 1.0 M KOH solution, saturated with CO2 gas for 30 minutes before use. CO2 was continuously introduced during the reaction at a flow rate of 25 mL / min. -1 The electrolyte circulation rate is 3.3 mL / min. -1 .

[0056] Performance was tested at -1.7 V (vs. RHE) potential using gas chromatography and... 1 Quantitative analysis of the products was performed using 1H NMR spectroscopy. The results showed a Faradaic efficiency of 23.6% for the hydrogen evolution reaction (HER) and 55.1% for the C2 products (ethylene, ethanol, etc.), corresponding to a current density of 244.8 mA·cm⁻¹. -2 .

[0057] In summary, this invention provides a non-noble metal @MOF topology-controlled catalyst for the electrocatalytic reduction of CO2 to C2 products. Compared with traditional catalyst preparation methods, this invention employs a one-step interfacial synthesis method at room temperature, with mild reaction conditions, simple operation, short reaction time, and easy industrial scale-up. The catalyst prepared by this invention is inexpensive and exhibits high activity and stability.

[0058] The applicant declares that the present invention is illustrated through the above embodiments, but the present invention is not limited to the above detailed methods, that is, it does not mean that the present invention must rely on the above detailed methods to be implemented. Those skilled in the art should understand that any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this invention fall within the protection and disclosure scope of this invention.

Claims

1. A one-step room-temperature interfacial synthesis method for preparing non-noble metal@MOF topology-controlled catalysts, characterized in that, Includes the following steps: (1) Prepare an aqueous solution of a metal salt, solution A; (2) Prepare functionalized ligand organic solution, solution B; (3) Solution A and solution B were subjected to an interfacial reaction at room temperature to obtain a non-noble metal@MOF topology-controlled catalyst precursor; (4) The precursor is washed and dried to obtain a non-noble metal@MOF topology-controlled catalyst.

2. The preparation method according to claim 1, characterized in that, Add the non-precious metal salt and stabilizer to the aqueous solvent and ultrasonically disperse until completely dissolved; maintain the natural dispersion state of the solution; The non-precious metal salt is selected from any one of copper acetate (Cu(Ac)2·2H2O), cobalt acetate (Co(Ac)2·4H2O), nickel acetate (Ni(Ac)2·4H2O), copper chloride (CuCl2·2H2O), and cobalt chloride (CoCl2·6H2O); The stabilizer is polyvinylpyrrolidone (PVP) K30, and the mass ratio of the non-precious metal salt to the stabilizer is 15:1 to 45:

1. The solvent is deionized water, and the concentration of non-precious metal salt is 50~100 mg / mL; each 4~8 mL of solvent corresponds to 10.0~30.0 mg of stabilizer.

3. The preparation method according to claim 1, characterized in that, The preparation method of the functionalized ligand solution in step (2) includes: dispersing the functionalized dicarboxylic acid ligand in a mixed solvent and ultrasonically dispersing for 5 to 10 minutes until completely dissolved; The functionalized dicarboxylic acid ligand is selected from any one of 2-methylterephthalic acid, 2,5-dimethylterephthalic acid, and terephthalic acid. The mixed solvent is a mixture of N,N-dimethylacetamide (DMAc) and ethyl acetate in a volume ratio of 1:1, with each 8-16 mL of the mixed solvent corresponding to 20.0-35.0 mg of functionalized dicarboxylic acid ligand.

4. The preparation method according to claim 1, characterized in that, The conditions for the room temperature interface reaction in step (3) are as follows: slowly add solution A to solution B and let it stand at room temperature of 25°C for 8 to 16 hours without additional stirring or heating.

5. The preparation method according to claim 1, characterized in that, The washing in step (4) involves washing with N,N-dimethylacetamide and anhydrous ethanol 2-3 times each; the drying is freeze drying for 10-14 hours.

6. The catalyst prepared by the method according to any one of claims 1-5.

7. The application of the catalyst prepared by the method according to any one of claims 1-5 for the electrocatalytic CO2RR preparation of C2 products.

8. The application according to claim 7 employs a three-electrode reaction system in a flowing electrolytic cell, wherein the working electrode is a gas diffusion electrode (GDE) supported on the catalyst, the reference electrode is Ag / AgCl (saturated KCl), and the counter electrode is nickel foam; the electrolyte of the reaction system is a 0.5~1.5M KOH solution, which needs to be saturated with CO2 gas for 20~40 minutes before use, and CO is continuously introduced into the system during the reaction. 2； The reaction conditions for the electrocatalytic CO2RR are as follows: reaction temperature is 20~25 ℃, applied potential range is -1.4 V~-1.9 V (vs. RHE), CO2 gas flow rate is 20~30 mL·min⁻¹, and electrolyte circulation flow rate is 2.5~4.0 mL·min⁻¹.

9. The application according to claim 8, the corresponding current density can be 200-500 mA / cm². 2 And at high current density (500 mA / cm²) 2 Under these conditions, it runs continuously for 10 hours.

10. The application according to any one of claims 7-9, for the electrocatalytic reduction of carbon dioxide (CO2RR) to prepare C2 products, said C2 products comprising one or more of ethylene and ethanol.

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