Graphite alkynyl copper platinum catalyst and preparation method thereof
By developing graphynyl copper-platinum catalysts on graphynyl substrates, the synergistic effect of Pt and Cu is used to solve the problem that platinum-based catalysts are easily poisoned by carbon monoxide in DMFC, and the improvement of catalytic activity and stability and cost reduction are achieved, which promotes the development of DMFC technology.
Patent Information
- Application Number
- CN202311163675.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-09-11
- Publication Date
- 2025-03-11
AI Technical Summary
In direct methanol fuel cells (DMFCs), platinum-based catalysts are easily poisoned by carbon monoxide during methanol oxidation reaction (MOR), resulting in a degradation of catalyst performance and limiting the large-scale commercialization of DMFCs.
By developing graphynyl copper-platinum catalysts on highly active graphynyl substrates, the synergistic effects between two metal atoms Pt and Cu and between metal atoms and carbon substrates are used to regulate the active center electronic structure, improve catalytic performance and reduce the amount of precious metal Pt.
It significantly improves the catalytic activity and long-term stability of methanol oxidation reaction (MOR), while reducing the preparation cost of catalysts, and promoting the development of DMFC technology.
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Figure CN119601688A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of catalyst design and preparation, and particularly relates to a graphene-based copper-platinum catalyst and a preparation method thereof. Background Art
[0002] Direct methanol fuel cells (DMFCs) are considered to be an ideal power source due to their good methanol fuel availability, low operating temperature, simple battery system, high energy conversion efficiency and low pollutant emissions. Currently, platinum-based catalysts are the most commonly used catalysts for the methanol oxidation reaction (MOR) in DMFCs. However, carbon monoxide (CO) produced during the MOR process will poison the platinum (Pt) catalyst, thereby seriously affecting the performance of DMFCs, which is one of the main factors limiting the large-scale commercialization of DMFCs. Therefore, improving the CO tolerance of the catalyst while ensuring its MOR activity is the main direction of this technology. A promising strategy is to combine Pt with another metal, especially a transition metal, to develop a bimetallic nanostructure, using the strong coupling between the two metals to achieve the regulation of the electronic structure of the active center, thereby synergistically optimizing the catalyst activity and life. In recent years, a large number of bimetallic catalysts have been studied, such as Pt-Ni (ChemCatChem, 2016, 8, 1410-1416), Pt-Co (Carbon, 2016, 96, 229-236), PtCu (J.Phys.Chem.C., 2016, 120, 10476-10484), etc., all of which can achieve partial improvement in the catalytic performance of MOR.
[0003] The cost control of the catalyst is also crucial to its practical application value. By dispersing Pt-based bimetallic nanomaterials on highly active low-dimensional carbon material carriers, the use of Pt can be reduced while improving the catalytic performance of MOR. Glotyn is a new type of carbon allotrope formed by sp and sp2 hybridized carbon, with a two-dimensional planar network chemical structure of diyne bonds and benzene rings conjugated. This special structure gives graphyne many unique properties, such as rich carbon chemical bonds, continuous large conjugated systems, wide interplanar spacing, outstanding mechanical and chemical stability, and semiconductor properties comparable to silicon, which makes it show broad application prospects in the field of catalysis (Chem. Soc. Rev., 2022, 51, 2681-2709). Therefore, a type of pt-transition metal catalyst supported by graphyne can be developed to meet the application requirements of high-performance MOR and DMFC. Summary of the invention
[0004] In view of the above problems, the present invention provides a method for preparing a graphene-based copper-platinum catalyst, comprising:
[0005] Take hexaethynylbenzene, cuprous iodide and pyridine to prepare a mixed solution;
[0006] Immersing the carbon cloth substrate in the mixed solution, heating and reacting under light-proof and inert gas protection conditions to obtain a carbon cloth loaded with graphyne in situ;
[0007] The carbon cloth loaded with graphyne in situ is cleaned and dried, and electrochemical reduction deposition is performed at a constant potential using graphyne as a working electrode, a graphite rod as a counter electrode, a saturated calomel electrode as a reference electrode, and an aqueous solution of copper salt and sodium citrate as an electrolyte to obtain a graphyne-based copper nanoparticle catalyst;
[0008] Immersing the graphene-based copper nanoparticle catalyst in a platinum source aqueous solution to perform ion exchange to obtain a platinum-doped catalyst;
[0009] The platinum-doped catalyst is cleaned, dried, and subjected to annealing heat treatment to obtain the graphene-based copper-platinum catalyst.
[0010] A further preferred technical solution is that the ratio of hexaethynylbenzene, cuprous iodide and pyridine is 10-40 mg: 1-2 mg: 10-40 mL.
[0011] A further preferred technical solution is: in the heating reaction, the reaction temperature is 60-130° C. and the reaction time is 12-72 h.
[0012] A further preferred technical solution is: in the aqueous solution of copper salt and sodium citrate, the copper salt is selected from one or a combination of copper chloride, copper sulfate, copper acetate, copper nitrate and corresponding hydrates, and the copper ion concentration in the aqueous solution is 1-20 mol / L.
[0013] A further preferred technical solution is that the concentration of sodium citrate in the aqueous solution is 1-50 mol / L.
[0014] A further preferred technical solution is: the constant potential is a fixed value in the range of 0.5-1.5V, and the electrochemical reduction deposition time is 50-500s.
[0015] A further preferred technical solution is: in the platinum source aqueous solution, the platinum source is chloroplatinic acid, potassium chloroplatinate or a combination of the two, and the platinum source concentration is 5-50 mol / L.
[0016] A further preferred technical solution is that the ion exchange treatment time is 0.5-24h.
[0017] A further preferred technical solution is: in the annealing heat treatment, the temperature is 300-600°C, the heating rate is 2°C / min-5°C / min, and the reaction time is 4-12h.
[0018] A further preferred technical solution is: a graphene-based copper-platinum catalyst, the preparation method of which is as above.
[0019] A new type of graphyne-based copper-platinum catalyst was developed on a highly active graphyne substrate using a simple in-situ electrodeposition + ion exchange method. The synergistic effect between Pt and Cu metal atoms and between metal atoms and carbon substrate was used to greatly improve the catalytic performance, while reducing the amount of precious metal Pt to reduce costs.
[0020] The purpose of the present invention is to provide a method for preparing a graphene-based copper-platinum catalyst and its product, which are applied to the electrocatalytic methanol oxidation reaction (MOR) to improve the MOR activity and long-term stability, while reducing the catalyst cost and promoting the development of DMFC technology.
[0021] The Graphene-based copper-platinum catalyst provided by the present invention has the following advantages:
[0022] (1) The in-situ electrochemical deposition method for preparing copper nanoparticles combined with the ion exchange method of the platinum source solution can not only obtain metal nanoparticle products with uniform size, but also effectively reduce the amount of precious metal platinum required for the catalyst and reduce the cost of catalyst preparation.
[0023] (2) Two-dimensional carbon graphyne was selected as the catalyst carrier. The acetylene-rich bond structure of graphyne and its uneven charge distribution effectively enhanced the charge interaction between the carrier and the active center, and promoted the uniform and stable anchoring of copper-platinum nanoparticles, which had a significant effect on improving the catalytic activity and stability of MOR.
[0024] The graphene-based copper-platinum catalyst prepared by this method has excellent catalytic performance for MOR, and the preparation process is simple and convenient, the preparation efficiency is high, and a certain scale production can be achieved.
[0025] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0027] Figure 1 The preparation process according to the present invention is shown;
[0028] Figure 2shows a scanning electron microscope photograph of sample 5 according to an embodiment of the present invention;
[0029] Figure 3 It shows that the unit catalyst mass current density of sample 5 according to the embodiment of the present invention reaches 5.26 mA / mgcat. at 0.63 V;
[0030] Figure 4 The MOR current density-time curve of sample 5 according to an embodiment of the present invention at a constant potential of 0.6 V is shown. DETAILED DESCRIPTION
[0031] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0032] Example 1
[0033] like Figure 1 As shown, the preparation steps of the graphene-based copper-platinum catalyst are as follows:
[0034] (1) Add 50 mg of hexaynylbenzene, 5 mg of cuprous iodide and 200 mL of pyridine into a reaction container, stir them magnetically to mix them evenly, and obtain a transparent solution. Then add a piece of carbon cloth and stop stirring. Pass nitrogen into the container and react at 110° C. for 72 h. After the reaction is completed, take out the carbon cloth loaded with graphyne in situ, wash it thoroughly, and dry it for later use.
[0035] (2) The carbon cloth loaded with graphyne in situ was fully cleaned and dried, and a three-electrode system was established, with the graphyne as the working electrode (cathode), the graphite rod as the counter electrode, and the saturated calomel electrode as the reference electrode. An aqueous solution containing 10 ml / L copper chloride dihydrate (CuCl2·2H2O) and 20 ml / L sodium citrate was used as the electrolyte. After the electrodes were fully infiltrated, electrochemical reduction deposition was performed for 300 s at a constant cathode potential of 0.8 V to obtain a graphyne-based copper nanoparticle catalyst.
[0036] (3) preparing a 10 ml / L potassium chloroplatinate aqueous solution, fully immersing the graphene-based copper nanoparticle catalyst therein, and performing ion exchange at room temperature and pressure for 6 hours to achieve platinum doping.
[0037] (4) The platinum-doped catalyst was thoroughly cleaned and dried, transferred to a programmed temperature tube furnace, heated to 400° C. at a heating rate of 2° C. / min under an inert gas atmosphere, and annealed for 6 h to obtain a graphyne-based copper-platinum catalyst sample 1.
[0038] Example 2
[0039] Preparation of graphene-based copper-platinum catalyst:
[0040] (1) Add 50 mg of hexaynylbenzene, 5 mg of cuprous iodide and 100 mL of pyridine into a reaction container, stir them magnetically to mix them evenly, and obtain a transparent solution. Then add a piece of carbon cloth and stop stirring. Pass nitrogen into the container and react at 110° C. for 72 h. After the reaction is completed, take out the carbon cloth loaded with graphyne in situ, wash it thoroughly, and dry it for later use.
[0041] (2) The carbon cloth loaded with graphyne in situ was fully cleaned and dried, and a three-electrode system was established, with the graphyne as the working electrode (cathode), the graphite rod as the counter electrode, and the saturated calomel electrode as the reference electrode. An aqueous solution containing 20 ml / L copper chloride dihydrate (CuCl2·2H2O) and 40 ml / L sodium citrate was used as the electrolyte. After the electrodes were fully infiltrated, electrochemical reduction deposition was performed for 300 s at a constant cathode potential of 1 V to obtain a graphyne-based copper nanoparticle catalyst.
[0042] (3) preparing a 20 ml / L potassium chloroplatinate aqueous solution, fully immersing the graphene-based copper nanoparticle catalyst therein, and performing ion exchange at room temperature and pressure for 4 h to achieve platinum doping.
[0043] (4) The platinum-doped catalyst was thoroughly cleaned and dried, transferred to a programmed temperature tube furnace, heated to 400°C at a heating rate of 2°C / min under an inert gas atmosphere, and annealed for 6 hours to obtain a graphyne-based copper-platinum catalyst sample 2.
[0044] Example 3
[0045] Preparation of graphene-based copper-platinum catalyst:
[0046] (1) Add 200 mg of hexaynylbenzene, 5 mg of cuprous iodide and 200 mL of pyridine into a reaction container, stir them magnetically to mix them evenly, and obtain a transparent solution. Then add a piece of carbon cloth and stop stirring. Pass nitrogen into the container and react at 110° C. for 72 h. After the reaction is completed, take out the carbon cloth loaded with graphyne in situ, wash it thoroughly, and dry it for later use.
[0047] (2) The carbon cloth loaded with graphyne in situ was fully cleaned and dried, and a three-electrode system was established, with the graphyne as the working electrode (cathode), the graphite rod as the counter electrode, and the saturated calomel electrode as the reference electrode. An aqueous solution containing 20 ml / L of copper sulfate pentahydrate (CuSO4·5H2O) and 40 ml / L of sodium citrate was used as the electrolyte. After the electrodes were fully infiltrated, electrochemical reduction deposition was performed for 500 s at a constant cathode potential of 1 V to obtain a graphyne-based copper nanoparticle catalyst.
[0048] (3) preparing a 10 ml / L potassium chloroplatinate aqueous solution, fully immersing the graphene-based copper nanoparticle catalyst therein, and performing ion exchange at room temperature and pressure for 6 hours to achieve platinum doping.
[0049] (4) The platinum-doped catalyst was thoroughly cleaned and dried, transferred to a programmed temperature tube furnace, heated to 450° C. at a heating rate of 2° C. / min under an inert gas atmosphere, and annealed for 6 h to obtain a graphyne-based copper-platinum catalyst sample 3.
[0050] Example 4
[0051] Preparation of graphene-based copper-platinum catalyst:
[0052] (1) Add 400 mg of hexaynylbenzene, 10 mg of cuprous iodide and 400 mL of pyridine into a reaction container, stir them magnetically to mix them evenly, and obtain a transparent solution. Then add a piece of carbon cloth and stop stirring. Pass nitrogen into the container and react at 110° C. for 72 h. After the reaction is completed, take out the carbon cloth loaded with graphyne in situ, wash it thoroughly, and dry it for later use.
[0053] (2) The carbon cloth loaded with graphyne in situ was fully cleaned and dried, and a three-electrode system was established, with the graphyne as the working electrode (cathode), the graphite rod as the counter electrode, and the saturated calomel electrode as the reference electrode. An aqueous solution containing 10 ml / L of copper sulfate pentahydrate (CuSO4·5H2O) and 20 ml / L of sodium citrate was used as the electrolyte. After the electrodes were fully infiltrated, electrochemical reduction deposition was performed for 200 s at a constant cathode potential of 1.2 V to obtain a graphyne-based copper nanoparticle catalyst.
[0054] (3) preparing a 20 ml / L potassium chloroplatinate aqueous solution, fully immersing the graphene-based copper nanoparticle catalyst therein, and performing ion exchange at room temperature and pressure for 6 hours to achieve platinum doping.
[0055] (4) The platinum-doped catalyst was thoroughly cleaned and dried, transferred to a programmed temperature tube furnace, heated to 450° C. at a heating rate of 2° C. / min under an inert gas atmosphere, and annealed for 6 h to obtain a graphyne-based copper-platinum catalyst sample 4.
[0056] Example 5
[0057] Preparation of graphene-based copper-platinum catalyst:
[0058] (1) Add 100 mg of hexaynylbenzene, 5 mg of cuprous iodide and 150 mL of pyridine into a reaction container, stir them magnetically to mix them evenly, and obtain a transparent solution. Then add a piece of carbon cloth and stop stirring. Pass nitrogen into the container and react at 110° C. for 72 h. After the reaction is completed, take out the carbon cloth loaded with graphyne in situ, wash it thoroughly, and dry it for later use.
[0059] (2) The carbon cloth loaded with graphyne in situ was fully cleaned and dried, and a three-electrode system was established, with the graphyne as the working electrode (cathode), the graphite rod as the counter electrode, and the saturated calomel electrode as the reference electrode. An aqueous solution containing 10 ml / L copper chloride dihydrate (CuCl2·2H2O) and 20 ml / L sodium citrate was used as the electrolyte. After the electrodes were fully infiltrated, electrochemical reduction deposition was performed for 200 s at a constant cathode potential of 1.2 V to obtain a graphyne-based copper nanoparticle catalyst.
[0060] (3) preparing a 10 ml / L potassium chloroplatinate aqueous solution, fully immersing the graphene-based copper nanoparticle catalyst therein, and performing ion exchange at room temperature and pressure for 8 h to achieve platinum doping.
[0061] (4) The platinum-doped catalyst was thoroughly cleaned and dried, transferred to a programmed temperature tube furnace, heated to 450° C. at a heating rate of 2° C. / min under an inert gas atmosphere, and annealed for 6 h to obtain a graphyne-based copper-platinum catalyst sample 5.
[0062] Figure 2 The scanning electron microscope photo of sample 5 is shown. It can be seen that the copper platinum nanoparticles have a particle size of about 10-30nm and are uniformly and densely loaded on the surface of Graphene. The MOR activity test was carried out in an acidic electrolyte (0.1mol / L HClO4+0.5mol / L CH3OH solution). Figure 3 As shown, sample 5 reaches a unit catalyst mass current density of 5.26 mA / mgcat. at 0.63 V, and its mass activity is 1.77 times that of commercial platinum carbon (20 wt.% Pt / C), which fully demonstrates that the graphyne-based copper-platinum catalyst obtained in the present invention can significantly improve the MOR catalytic activity and reduce the catalyst cost. Figure 4 The MOR current density-time curve of sample 5 at a constant potential of 0.6 V is shown, which shows that the MOR stability of the graphyne-based copper-platinum catalyst is good and the performance is significantly improved.
[0063] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for preparing a graphene-based copper-platinum catalyst, characterized in that: include: Take hexaethynylbenzene, cuprous iodide and pyridine to prepare a mixed solution; Immersing the carbon cloth substrate in the mixed solution, heating and reacting under light-proof and inert gas protection conditions to obtain a carbon cloth loaded with graphyne in situ; The carbon cloth loaded with graphyne in situ is cleaned and dried, and electrochemical reduction deposition is performed at a constant potential using graphyne as a working electrode, a graphite rod as a counter electrode, a saturated calomel electrode as a reference electrode, and an aqueous solution of copper salt and sodium citrate as an electrolyte to obtain a graphyne-based copper nanoparticle catalyst; Immersing the graphene-based copper nanoparticle catalyst in a platinum source aqueous solution to perform ion exchange to obtain a platinum-doped catalyst; The platinum-doped catalyst is cleaned, dried, and subjected to annealing heat treatment to obtain the graphene-based copper-platinum catalyst.
2. The method for preparing a graphene-based copper-platinum catalyst according to claim 1, characterized in that: The ratio of hexaethynylbenzene, cuprous iodide and pyridine is 10-40 mg: 1-2 mg: 10-40 mL.
3. A method for preparing a graphene-based copper-platinum catalyst according to claim 1, characterized in that: In the heating reaction, the reaction temperature is 60-130° C. and the reaction time is 12-72 h.
4. The method for preparing a graphene-based copper-platinum catalyst according to claim 1, characterized in that: In the aqueous solution of copper salt and sodium citrate, the copper salt is selected from one or a combination of copper chloride, copper sulfate, copper acetate, copper nitrate and corresponding hydrates, and the copper ion concentration in the aqueous solution is 1-20 mol / L.
5. The method for preparing a graphene-based copper-platinum catalyst according to claim 4, characterized in that: In the aqueous solution, the concentration of sodium citrate is 1-50 mol / L.
6. The method for preparing a graphene-based copper-platinum catalyst according to claim 1, characterized in that: The constant potential is a fixed value in the range of 0.5-1.5V, and the electrochemical reduction deposition time is 50-500s.
7. The method for preparing a graphene-based copper-platinum catalyst according to claim 1, characterized in that: In the platinum source aqueous solution, the platinum source is chloroplatinic acid, potassium chloroplatinate or a combination of the two, and the concentration of the platinum source is 5-50 mol / L.
8. The method for preparing a graphene-based copper-platinum catalyst according to claim 1, characterized in that: The treatment time of the ion exchange is 0.5-24h.
9. The method for preparing a graphene-based copper-platinum catalyst according to claim 1, characterized in that: In the annealing heat treatment, the temperature is 300-600° C., the heating rate is 2° C. / min-5° C. / min, and the reaction time is 4-12 hours.
10. A graphene-based copper-platinum catalyst, characterized in that: Prepared by the method according to any one of claims 1 to 9.