Pulse current-enhanced MOF-based catalyst, preparation method therefor and use thereof
By generating active centers in situ in two-dimensional MOF-based materials and treating them with pulsed current to change the surface state of Cu nanoparticles, the problem of poor product selectivity in the CO2 electroreduction process of Cu-based catalysts was solved, and efficient synthesis of multi-carbon products was achieved.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-06-04
- Publication Date
- 2026-04-02
AI Technical Summary
Cu-based catalysts exhibit poor product selectivity and low activity during CO2 electroreduction, making it difficult to efficiently and directionally synthesize multi-carbon products.
By employing a pulsed current treatment method, active centers are generated in situ in the two-dimensional MOF-based material Cu-TCPP. The surface roughness and valence state of Cu nanoparticles are altered by the pulsed current, resulting in an uneven distribution of oxidized and reduced Cu, thereby enhancing the reaction selectivity of the catalyst.
The reaction selectivity and efficiency of CO2 electroreduction to multi-carbon products were improved, with the Faraday efficiency of ethylene reaching 28.8% and the Faraday efficiency of carbon-containing products reaching over 50%.
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Abstract
Description
Pulse current enhanced MOF-based catalyst and preparation method and application thereof
[0001] Cross-reference to related applications
[0002] The present application claims priority to Chinese Patent Application No. 202411374770.2, filed on September 29, 2024, entitled "Pulse current enhanced MOF-based catalyst and preparation method and application thereof", the entire contents of which are incorporated herein by reference. TECHNICAL FIELD
[0003] The present application belongs to the technical field of catalytic materials for air pollutant control, and particularly relates to a pulse current enhanced MOF-based catalyst and a preparation method and application thereof. BACKGROUND
[0004] CO2, as a major greenhouse gas, has become increasingly prominent in environmental problems. With the proposal of the "carbon peak and carbon neutral" goal, the storage and utilization of CO2 have become the focus of attention. The goal is to reduce carbon emissions and promote the recycling of carbon to achieve a green and low-carbon transformation of the economy. In this transformation process, CO2 storage and efficient conversion and utilization technologies are particularly important, as they are not only key means to mitigate climate change, but also an important direction for the development of new energy industries.
[0005] Electric energy, as a stable and readily available energy source, has great potential for development through electrically driven catalytic conversion of CO2. Not only can this greenhouse gas be converted into valuable chemicals or fuels, but also the process of energy storage and conversion can be zero-emission, which is of great significance for building a low-carbon circular economy system. However, the current development of CO2 electroreduction technology still faces many bottlenecks, the most prominent of which is the limitation of product distribution.
[0006] Currently, the products of CO2 electroreduction are mainly focused on CO, methane and other single-carbon products with low added value. In order to achieve high-value utilization of CO2 resources, scientists are committed to exploring catalytic systems that can promote C-C coupling in order to obtain two-carbon or even multi-carbon products with higher value.
[0007] Copper-based catalysts are considered to be one of the effective ways to achieve the conversion of CO2 to multi-carbon products, but they still face severe challenges in practical applications. First, the product selectivity of Cu-based catalysts is poor, i.e., under the same reaction conditions, multiple products are often generated simultaneously, making it difficult to efficiently and directionally synthesize target products; second, the activity of Cu-based catalysts needs to be improved to meet the requirements of industrial production in terms of efficiency and yield. Therefore, how to design and optimize Cu-based catalysts to improve their selectivity and catalytic activity for specific multi-carbon products has become a key scientific problem that needs to be solved in the field of CO2 electroreduction. SUMMARY
[0008] The present application aims to overcome the above-mentioned shortcomings of the prior art, and provides a pulse current enhanced MOF-based catalyst, a preparation method and application thereof, which solves the problems of poor product selectivity and low activity of Cu-based catalysts in the electro-reduction of CO2 to multi-carbon products.
[0009] To achieve the above-mentioned purpose, the present application provides the following technical solutions:
[0010] The present application provides a preparation method of a pulse current enhanced MOF-based catalyst, comprising:
[0011] dissolving a copper salt and polyvinylpyrrolidone in a mixed solution of N,N-dimethylformamide and ethanol, and then adding formic acid to obtain an A solution;
[0012] dissolving Cu-TCPP in a mixed solution of DMF and ethanol to obtain a B solution;
[0013] dispersing the A solution and the B solution uniformly and drying by heating to obtain PML-Cu;
[0014] calcining PML-Cu under an inert atmosphere to obtain PML-CuNPs;
[0015] treating PML-CuNPs with a pulse current under an inert atmosphere to obtain Pulse-PML-CuNPs.
[0016] The mass ratio of the copper salt, polyvinylpyrrolidone and Cu-TCPP is (20-25) : 100 : (45-50).
[0017] The copper salt is Cu(NO3)2·3H2O or CuCl2·2H2O.
[0018] The dispersing of the A solution and the B solution uniformly and drying by heating to obtain PML-Cu is specifically:
[0019] The A solution and the B solution are mixed and dispersed uniformly, and heated in an oven at 80-100℃ for 8-10 hours.
[0020] The calcining of PML-Cu under an inert atmosphere to obtain PML-CuNPs is specifically:
[0021] PML-Cu is calcined in an inert gas at a temperature of 250-280℃ for 2-3 hours to obtain PML-CuNPs.
[0022] The treating of PML-CuNPs with a pulse current under an inert atmosphere to obtain Pulse-PML-CuNPs is specifically:
[0023] The PML-CuNPs are dispersed with a volatile solvent and coated on a working electrode, and the PML-CuNPs are treated by pulse current in an electrolyte by using a three-electrode system under an inert atmosphere to obtain Pulse-PML-CuNPs.
[0024] The Pulse-PML-CuNPs are obtained by treating the PML-CuNPs by pulse current, and specifically:
[0025] The PML-CuNPs are treated by pulse current with a lower limit of -0.5 V and an upper limit of +1 V, and the PML-CuNPs are pulsed every 1 s from a negative potential for 30 s of pulse treatment to obtain Pulse-PML-CuNPs.
[0026] The electrolyte is a 0.1-0.2 mol / L KHCO3 solution.
[0027] The application also provides a Pulse-PML-CuNPs prepared by the above preparation method.
[0028] The application also provides an application of the Pulse-PML-CuNPs in the field of CO2 electroreduction.
[0029] Compared with the prior art, the application has the beneficial effects that:
[0030] The application provides a preparation method of a Pulse-PML-CuNPs, which generates active centers in-situ in a two-dimensional MOF-based material Cu-TCPP by a node metal in-situ reduction method, does not need to introduce active sites from outside, and is convenient to operate. The synthesized two-dimensional MOF-based electrocatalyst PML-CuNPs has a monatomic layer structure, can maximize the mass transfer rate, and greatly improves the reaction rate. The application also changes the surface state of the active center by a pulse current method, changes the surface roughness and valence state of the Cu nanoparticles, enhances the reaction selectivity of CO2 electroreduction to multi-carbon products, and realizes the result of high selectivity of the product to ethylene.
[0031] The Pulse-PML-CuNPs provided by the application are treated by pulse current, and the surface of the CuNPs is partially oxidized under an oxidation potential and is partially reduced under a reduction potential. After multiple pulses, the CuNPs present uneven distribution of oxidized Cu and reduced Cu, so that the surface roughness of the catalyst is increased and the distribution ratio of the oxidized Cu is increased. Studies have shown that the oxidized Cu is more conducive to the production of multi-carbon products.
[0032] The catalyst prepared by the application is used for a catalytic reaction of CO2 electroreduction to multi-carbon products, and the Faraday efficiency of ethylene reaches 28.8% and the Faraday efficiency of carbon-containing products reaches more than 50% under an optimal potential. Attached Figure Description
[0033] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below:
[0034] Figure 1 is a schematic diagram of the principle of using the catalyst prepared in this application for the electrocatalytic reduction of CO2 to C2H4;
[0035] Figure 2 shows the voltage curve during the pulse processing of this application;
[0036] Figure 3 shows the distribution of electrocatalytic CO2 reduction products of PML-CuNPs prepared in Example 1 under 0.1 mol / L KHCO3 electrolyte conditions;
[0037] Figure 4 shows the distribution of electrocatalytic CO2 reduction products of Pulse-PML-CuNPs prepared in Example 2 under 0.1 mol / L KHCO3 electrolyte conditions;
[0038] Figure 5 shows the distribution of electrocatalytic CO2 reduction products of Pulse-PML-CuNPs prepared in Example 3 under 0.5 mol / L KHCO3 electrolyte conditions. Detailed Implementation
[0039] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.
[0040] Metal-organic frameworks (MOFs) are a new class of crystalline porous materials whose metal nodes and bridging ligands possess excellent designability and tailorability. Different applications can be achieved through the rational combination and functionalization of various components. Therefore, MOF-based materials have attracted widespread attention in numerous fields.
[0041] The application is based on a two-dimensional MOF-based catalyst with Cu as a metal node. By annealing treatment under a low-temperature N2 atmosphere, a part of the Cu nodes is reduced to Cu nanoparticles. Then, the Cu nanoparticles are further treated by pulse current to change the surface roughness and valence of the Cu nanoparticles, so as to realize the coexistence of oxidized and reduced Cu on the surface of the Cu nanoparticles and enhance the performance of the catalyst for the electro-reduction of CO2 to multi-carbon products.
[0042] The application will be further described below in combination with the drawings:
[0043] A preparation method of a pulse current-enhanced MOF-based catalyst, comprising the following steps:
[0044] Dissolve a copper salt and polyvinylpyrrolidone in a mixed solution of N,N-dimethylformamide (DMF) and ethanol, and then add formic acid to obtain an A solution;
[0045] Dissolve Cu-TCPP in a mixed solution of DMF and ethanol to obtain a B solution;
[0046] Disperse the A solution and the B solution uniformly, heat and dry to obtain a purple-red powder, denoted as PML-Cu;
[0047] Under an inert atmosphere, calcine the PML-Cu to obtain a red powder, denoted as PML-CuNPs;
[0048] Under an inert atmosphere, treat the PML-CuNPs by pulse current to obtain a powder, denoted as Pulse-PML-CuNPs.
[0049] The application will be further described below:
[0050] In some embodiments, the addition ratio of the copper salt, polyvinylpyrrolidone and Cu-TCPP is (20-25) : 100 : (45-50). It should be noted that an appropriate amount of copper salt can ensure that there are enough copper ions to combine with the TCPP ligand to form a stable and functional Cu-TCPP complex; the amount of polyvinylpyrrolidone can effectively disperse and stabilize other components without causing excessive negative effects on the system.
[0051] In some embodiments, the copper salt is Cu(NO3)2·3H2O or CuCl2·2H2O. It should be noted that these two copper salts have good solubility and provide the required copper ions for the reaction.
[0052] In some embodiments, the mixing ratio of N,N-dimethylformamide and ethanol is (2-3) : 1.
[0053] In some embodiments, the A solution and the B solution are uniformly dispersed, heated and dried to obtain a purple red powder, denoted as PML-Cu, specifically:
[0054] The A solution and the B solution are uniformly mixed in a reaction kettle with a polytetrafluoroethylene liner, and heated in an oven at 80-100°C for 8-10 hours. It should be noted that by adjusting the temperature and heating time, the reaction rate and yield of the product can be controlled, and the structure and performance of PML-Cu can be adjusted.
[0055] In some embodiments, PML-Cu is calcined in an inert gas to obtain a red powder, specifically:
[0056] Under an inert atmosphere, PML-Cu is placed in a heat-resistant container (magnetic boat, crucible, etc.) and placed in a tube furnace, and calcined at 250-280°C for 2-3 hours to obtain a red powder, denoted as PML-CuNPs. It should be noted that PML-Cu is reduced to Cu nanoparticles by calcination at this temperature and time, and the uniform distribution of Cu nanoparticles in the PML matrix results in PML-CuNPs with a monolayer structure, which maximizes the mass transfer rate.
[0057] In some embodiments, under an inert atmosphere, PML-CuNPs are treated using pulse current to obtain a product denoted as Pulse-PML-CuNPs, specifically:
[0058] PML-CuNPs are dispersed with a volatile solvent (ethanol, methanol, acetone, etc.) and coated on carbon paper or carbon cloth as a working electrode. Using a three-electrode system (Ag / AgCl electrode as a reference electrode, Pt electrode as a counter electrode, and working electrode), PML-CuNPs are treated by pulse current in an electrolyte under an inert atmosphere to obtain Pulse-PML-CuNPs.
[0059] The minimum potential of the pulse current is -0.5V and the maximum potential is +1.0V. Starting from the negative potential, the PML-CuNPs are pulsed every 1s for 30s to obtain Pulse-PML-CuNPs. It should be noted that under the oxidation potential, the surface of CuNPs will be partially oxidized, and under the reduction potential, some reduction will occur. After multiple pulses, CuNPs will exhibit uneven distribution of oxidized and reduced Cu, increasing the surface roughness of the catalyst and increasing the proportion of oxidized Cu. Oxidized Cu is more conducive to the production of multi-carbon products.
[0060] The electrolyte is a 0.1-0.2mol / L KHCO3 solution.
[0061] Electrocatalytic CO2 reduction reaction:
[0062] The prepared catalyst was coated on carbon paper as a working electrode in a three-electrode system, and CO2 was reduced to multi-carbon products in a CO2 atmosphere in a KHCO3 solution for performance testing.
[0063] In order to better illustrate the purpose, technical scheme and advantages of the present application, the present application will be further described below in conjunction with specific examples.
[0064] In the following examples, each material used can be obtained through ordinary channels unless otherwise specified; the test method used is a conventional method in the art.
[0065] Example 1
[0066] PML-Cu: 2.4 mg of Cu(NO3)2·3H2O and 10 mg of polyvinylpyrrolidone were dissolved in a mixed solution of 9 ml of N,N-dimethylformamide (DMF) and 3 ml of ethanol, and 40 ul of formic acid was added to form A liquid. 4.7 mg of Cu-TCPP was dissolved in a mixed solution of 3 ml of DMF and 1 ml of ethanol to form B liquid. A and B were mixed in a reaction kettle lined with polytetrafluoroethylene, placed in an 80°C oven for 8 hours, washed with ethanol after cooling, and dried to obtain a purple red powder, which was denoted as PML-Cu.
[0067] PML-CuNPs: 20 mg of PML-Cu was weighed in a magnetic boat and placed in a tube furnace, calcined at 250°C for 2 hours under a nitrogen atmosphere to obtain a red powder, which was denoted as PML-CuNPs;
[0068] The electrocatalytic CO2 reduction reaction of the catalyst prepared in this example was carried out in a 0.1 mol / L KHCO3 electrolyte.
[0069] Example 2
[0070] PML-Cu: 4.8 mg of Cu(NO3)2·3H2O and 20 mg of polyvinylpyrrolidone were dissolved in a mixed solution of 18 ml of N,N-dimethylformamide (DMF) and 6 ml of ethanol, and 80 ul of formic acid was added to form A liquid. 9.4 mg of Cu-TCPP was dissolved in a mixed solution of 6 ml of DMF and 2 ml of ethanol to form B liquid. A and B were mixed in a reaction kettle lined with polytetrafluoroethylene, placed in an 80°C oven for 8 hours, washed with ethanol after cooling, and dried to obtain a purple red powder, which was denoted as PML-Cu.
[0071] PML-CuNPs: 20 mg of PML-Cu was weighed in a magnetic boat and placed in a tube furnace, calcined at 260°C for 2 hours under a nitrogen atmosphere to obtain a red powder, which was denoted as PML-CuNPs;
[0072] Pulse-PML-CuNPs: PML-CuNPs were dispersed with ethanol and coated on carbon paper, using a three-electrode system (Ag / AgCl electrode as reference electrode, Pt electrode as counter electrode, and the catalyst coated on carbon paper as working electrode), in 0.1 mol / L KHCO3 solution, under N2 atmosphere, PML-CuNPs were treated with pulse current with lower limit -0.5 V and upper limit +1 V, and Pulse-PML-CuNPs were obtained after treatment. The voltage change with time is shown in Figure 2.
[0073] The electrocatalytic CO2 reduction reaction of the catalyst prepared in this example was carried out in 0.1 mol / L KHCO3 electrolyte.
[0074] Example 3
[0075] PML-Cu: 2.4 mg of Cu(NO3)2·3H2O and 10 mg of polyvinylpyrrolidone were dissolved in a mixed solution of 9 ml of N,N-dimethylformamide (DMF) and 3 ml of ethanol, and 40 ul of formic acid was added to form A liquid. 4.7 mg of Cu-TCPP was dissolved in a mixed solution of 3 ml of DMF and 1 ml of ethanol to form B liquid. A and B were mixed in a reaction kettle lined with polytetrafluoroethylene, and placed in an 80°C oven for 10 hours. After cooling, it was washed with ethanol and dried to obtain a purple red powder, which was recorded as PML-Cu.
[0076] PML-CuNPs: 20 mg of PML-Cu was weighed in a magnetic boat and placed in a tube furnace, and calcined at 280°C for two hours under nitrogen atmosphere to obtain a red powder, which was recorded as PML-CuNPs;
[0077] Pulse-PML-CuNPs: PML-CuNPs were dispersed with ethanol and coated on carbon paper, using a three-electrode system (Ag / AgCl electrode as reference electrode, Pt electrode as counter electrode, and the catalyst coated on carbon paper as working electrode), in 0.2 mol / L KHCO3 solution, under N2 atmosphere, PML-CuNPs were treated with pulse current with lower limit -0.5 V and upper limit +1 V, and Pulse-PML-CuNPs were obtained after treatment. The voltage change with time is shown in Figure 2.
[0078] The electrocatalytic CO2 reduction reaction of the catalyst prepared in this example was carried out in 0.5 mol / L KHCO3 electrolyte.
[0079] As shown in FIG. 3 and FIG. 4, the catalytic results show that the main product of the Pulse-PML-CuNPs catalyst after pulse treatment is ethylene, and the faradic efficiency of ethylene reaches 28.8% at the optimal potential, and the faradic efficiency of carbon-containing products reaches more than 50%. The main product of the PML-CuNPs catalyst without pulse treatment is CO and methane, which are single-carbon products, and the faradic efficiency of ethylene is only 12.9%. There is a big difference between the two in the types of reduction products and faradic efficiency, which is closely related to the surface roughness and valence state of the active center Cu. After pulse treatment, the surface of CuNPs will be partially oxidized at the oxidation potential, and partially reduced at the reduction potential. After multiple pulses, CuNPs will show uneven distribution of oxidized and reduced Cu, which increases the surface roughness of the catalyst and the proportion of oxidized Cu. Studies have shown that oxidized Cu is more conducive to the production of multi-carbon products.
[0080] As shown in FIG. 5, the CO2 electro-reduction reaction was carried out in 0.5 mol / L KHCO3 electrolyte, and the faradic efficiency of ethylene was only 22.1% at the optimal potential. The buffer capacity of 0.5 mol / L KHCO3 is weaker than that of 0.1 mol / L KHCO3, and the pH at the electrode surface is higher, which is not conducive to the production of multi-carbon products.
[0081] Example 4
[0082] PML-Cu: 4 mg of Cu(NO3)2·3H2O and 20 mg of polyvinylpyrrolidone were dissolved in a mixed solution of 18 ml of N,N-dimethylformamide (DMF) and 6 ml of ethanol, and then 80 ul of formic acid was added to form solution A. 10 mg of Cu-TCPP was dissolved in a mixed solution of 6 ml of DMF and 2 ml of ethanol to form solution B. A and B were mixed in a reaction kettle lined with polytetrafluoroethylene, placed in a 100°C oven for 10 hours, washed with ethanol after cooling, dried to obtain a purple red powder, and marked as PML-Cu.
[0083] PML-CuNPs: 20 mg of PML-Cu was weighed in a magnetic boat and placed in a tube furnace, and calcined at 280°C for 3 hours under nitrogen atmosphere to obtain a red powder, marked as PML-CuNPs;
[0084] Pulse-PML-CuNPs: PML-CuNPs were dispersed with ethanol and coated on carbon paper, using a three-electrode system (Ag / AgCl electrode as reference electrode, Pt electrode as counter electrode, and the catalyst coated on carbon paper as working electrode), in 0.2 mol / L KHCO3 solution, under N2 atmosphere, PML-CuNPs were treated with pulse current with lower limit -0.5 V and upper limit +1 V, Pulse-PML-CuNPs were obtained after treatment. The voltage change with time is shown in Figure 2.
[0085] Example 5
[0086] PML-Cu: 5 mg Cu(NO3)2·3H2O and 20 mg polyvinylpyrrolidone were dissolved in a mixed solution of 18 ml N,N-dimethylformamide (DMF) and 6 ml ethanol, and 80 ul formic acid was added, which was referred to as A liquid. 9 mg Cu-TCPP was dissolved in a mixed solution of 6 ml DMF and 2 ml ethanol, which was referred to as B liquid. A and B were mixed in a reaction kettle with a polytetrafluoroethylene liner, placed in a 90°C oven for 10 hours, washed with ethanol after cooling, dried, and a purple red powder was obtained, which was referred to as PML-Cu.
[0087] PML-CuNPs: 20 mg PML-Cu was weighed in a magnetic boat and placed in a tube furnace, calcined at 260°C for 3 hours under nitrogen atmosphere, and a red powder was obtained, which was referred to as PML-CuNPs;
[0088] Pulse-PML-CuNPs: PML-CuNPs were dispersed with ethanol and coated on carbon paper, using a three-electrode system (Ag / AgCl electrode as reference electrode, Pt electrode as counter electrode, and the catalyst coated on carbon paper as working electrode), in 0.2 mol / L KHCO3 solution, under N2 atmosphere, PML-CuNPs were treated with pulse current with lower limit -0.5 V and upper limit +1 V, Pulse-PML-CuNPs were obtained after treatment. The voltage change with time is shown in Figure 2.
[0089] Example 6
[0090] PML-Cu: 5 mg Cu(NO3)2·3H2O and 20 mg polyvinylpyrrolidone were dissolved in a mixed solution of 18 ml N,N-dimethylformamide (DMF) and 6 ml ethanol, and 80 ul formic acid was added, which was referred to as A liquid. 9 mg Cu-TCPP was dissolved in a mixed solution of 6 ml DMF and 2 ml ethanol, which was referred to as B liquid. A and B were mixed in a reaction kettle with a polytetrafluoroethylene liner, placed in a 90°C oven for 10 hours, washed with ethanol after cooling, dried, and a purple red powder was obtained, which was referred to as PML-Cu.
[0091] PML-CuNPs: 20 mg PML-Cu was weighed in a magnetic boat and put into a tube furnace, calcined at 280 °C for 3 hours under nitrogen atmosphere, to obtain a red powder, which was recorded as PML-CuNPs;
[0092] Pulse-PML-CuNPs: PML-CuNPs was dispersed with ethanol and coated on carbon paper, using a three-electrode system (Ag / AgCl electrode as reference electrode, Pt electrode as counter electrode, and catalyst coated on carbon paper as working electrode), in 0.1 mol / L KHCO3 solution, under N2 atmosphere, PML-CuNPs was treated with pulse current with lower limit -0.5 V and upper limit +1 V, and Pulse-PML-CuNPs was obtained after treatment. The voltage change with time is shown in Figure 2.
[0093] Example 7
[0094] PML-Cu: 4.8 mg CuCl2·2H2O and 20 mg polyvinylpyrrolidone were dissolved in a mixed solution of 18 ml N,N-dimethylformamide (DMF) and 6 ml ethanol, and 80 ul formic acid was added, which was recorded as A liquid. 9.4 mg Cu-TCPP was dissolved in a mixed solution of 6 ml DMF and 2 ml ethanol, which was recorded as B liquid. A and B were mixed in a reaction kettle with a polytetrafluoroethylene liner, placed in a 100 °C oven for 10 hours, washed with ethanol after cooling, dried, and a purple red powder was obtained, which was recorded as PML-Cu.
[0095] PML-CuNPs: 20 mg PML-Cu was weighed in a magnetic boat and put into a tube furnace, calcined at 280 °C for 3 hours under nitrogen atmosphere, to obtain a red powder, which was recorded as PML-CuNPs;
[0096] Pulse-PML-CuNPs: PML-CuNPs was dispersed with ethanol and coated on carbon paper, using a three-electrode system (Ag / AgCl electrode as reference electrode, Pt electrode as counter electrode, and catalyst coated on carbon paper as working electrode), in 0.1 mol / L KHCO3 solution, under N2 atmosphere, PML-CuNPs was treated with pulse current with lower limit -0.5 V and upper limit +1 V, and Pulse-PML-CuNPs was obtained after treatment. The voltage change with time is shown in Figure 2.
[0097] The endpoints and any values of the ranges disclosed in this application are not limited to the precise ranges or values; such ranges or values should be understood to include values close to them. For numerical ranges, the endpoint values of the various ranges, the endpoint values of the various ranges and individual point values, and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. In principle, various technical solutions can be combined with each other to obtain new technical solutions, which should also be considered as specifically disclosed herein.
[0098] The above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to the above embodiments, those skilled in the art can still make modifications or equivalent substitutions to the specific implementation methods of this application. Any modifications or equivalent substitutions that do not depart from the spirit and scope of this application are within the protection scope of the claims of this application pending approval.
Claims
1. A method for the preparation of a pulse current enhanced MOF-based catalyst, characterized in that, The application relates to a preparation method of a pulse current enhanced MOF-based catalyst. A solution is prepared by dissolving a copper salt and polyvinylpyrrolidone in a mixed solution of N, N-dimethylformamide and ethanol, and adding formic acid; A B solution is prepared by dissolving Cu-TCPP in a mixed solution of DMF and ethanol; The A solution and the B solution are uniformly dispersed, and PML-Cu is obtained by heating and drying; PML-CuNPs are obtained by calcining PML-Cu under an inert atmosphere; Pulse-PML-CuNPs are obtained by treating PML-CuNPs with a pulse current under an inert atmosphere.
2. A method of preparing a pulsed current enhanced MOF-based catalyst according to claim 1, characterized in that, The mass ratio of the copper salt, polyvinylpyrrolidone and Cu-TCPP is (20-25):100:(45-50).
3. A method of preparing a pulsed current enhanced MOF-based catalyst according to claim 1, wherein, The copper salt is Cu(NO3)2.3H2O or CuCl2.2H2O.
4. The method of claim 1, wherein the pulse current is applied at a current density of 0.1 mA / cm2 to 100 mA / cm2. The A solution and the B solution are uniformly dispersed, and PML-Cu is obtained by heating and drying. The A solution and the B solution are uniformly dispersed and mixed, and are heated in an oven at 80-100 DEG C for 8-10 hours.
5. The method of claim 1, wherein the pulse current is applied at a current density of 0.1 mA / cm2 to 100 mA / cm2. PML-CuNPs are obtained by calcining PML-Cu under an inert atmosphere. PML-CuNPs are obtained by calcining PML-Cu at a temperature of 250-280 DEG C under an inert gas for 2-3 hours.
6. The method of claim 1, wherein the pulse current is applied at a current density of 0.1 mA / cm2 to 100 mA / cm2. Pulse-PML-CuNPs are obtained by treating PML-CuNPs with a pulse current under an inert atmosphere. PML-CuNPs are dispersed in a volatile solvent and coated on a working electrode, and Pulse-PML-CuNPs are obtained by treating PML-CuNPs with a pulse current in an electrolyte under a three-electrode system in an inert atmosphere.
7. A method of preparing a pulsed current enhanced MOF-based catalyst according to claim 6, wherein, Pulse-PML-CuNPs are obtained by treating PML-CuNPs with a pulse current. Pulse-PML-CuNPs are obtained by treating PML-CuNPs with a pulse current with a lower limit of -0.5 V and an upper limit of +1 V, and the pulse current is applied every 1 s from a negative potential for 30 s.
8. The method of claim 6, wherein the pulse current is applied at a current density of 0.1 mA / cm2 to 100 mA / cm2, a pulse frequency of 0.1 Hz to 1000 Hz, and a duty cycle of 0.1% to 99.9%. The electrolyte is a 0.1-0.2 mol / L KHCO3 solution.
9. A pulse current enhanced MOF-based catalyst prepared by the preparation method in any one of claims 1-8.
10. Application of the pulse current enhanced MOF-based catalyst in claim 9 in the field of CO2 electro-reduction.