Preparation method of porous carbon supported metal electrocatalyst
The spray drying method combined with the template method was used to prepare porous carbon-supported metal electrocatalysts, which solved the problems of unfavorable agglomeration and pore size distribution of platinum nanoparticles in existing catalysts, and achieved efficient and low-cost electrocatalytic performance.
Patent Information
- Application Number
- CN202411955936.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-28
- Publication Date
- 2025-03-21
AI Technical Summary
Among the existing electrolytic water hydrogen production catalysts and fuel cell oxygen reduction catalysts, platinum nanoparticles are prone to agglomeration, and the pore size distribution of the carrier is not conducive to the circulation of the electrolyte and the overflow of gas, resulting in high costs, insufficient activity and stability.
A spherical three-dimensional porous network structure was prepared by spray drying combined with the template method. By dissolving the water-soluble carbon source, metal salt and template in water, spray drying and high-temperature heating, a spherical three-dimensional porous network structure was formed, and metal nanoparticles were loaded.
The high specific surface area and porosity of the electrocatalyst are achieved, mass transfer is promoted, electrocatalytic performance is improved, cost is reduced, and is suitable for macro-preparation.
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Figure CN119663343A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a method for preparing a porous carbon-supported metal electrocatalyst, and belongs to the technical field of new energy materials related to hydrogen production by electrolysis of water and fuel cell catalysts. Background Art
[0003] Currently, commercial water electrolysis hydrogen production catalysts, fuel cell oxygen reduction catalysts, and hydrogen oxidation catalysts are porous carbon-supported platinum metal. The preparation process is complicated and costly, platinum nanoparticles are easy to agglomerate, and the pore size distribution of the carrier is not conducive to the circulation of electrolyte and gas overflow. Guided by the demand for high activity, high stability, and low cost, low-platinum catalysts and non-platinum catalysts have become two important research directions. Low-platinum catalysts reduce the amount of platinum by changing the catalyst structure and alloying with other metals, and non-platinum catalysts replace metal platinum with non-precious metal catalysts. At this stage, both are difficult to apply to commercial mass production.
[0004] Spray drying is a common method for preparing powders. It can quickly convert a solution (or slurry) into dry powder in one step. It is one of the commonly used methods for preparing catalysts. It is simple to operate and can be produced continuously, making it very suitable for industrial production.
[0005] From the above analysis, we can know that the porous carbon-supported metal electrocatalyst can be prepared by spray drying combined with template method. The supported metal can be atoms, clusters, particles and other sizes, which can reduce the cost of electrocatalysts. Its high specific surface area and porosity can promote mass transfer, and the supported metal nanoparticles can improve its electrocatalytic performance. This preparation method can realize the large-scale preparation of electrocatalysts. Summary of the invention
[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to develop a method for preparing a porous carbon-supported metal electrocatalyst. The electrocatalyst prepared by the method is composed of porous carbon supporting many metals (atoms, clusters or particles) and presents a spherical three-dimensional porous network structure. Among them, the size of the sphere is 0.1-100 μm, the three-dimensional porous network has many macropores and mesopores, the pore size of the macropore is 0.1-10 μm, and the mesopores of 2-50 nm are distributed on the pore wall of the macropore; the size range of the supported metal is 0.1-100 nm.
[0007] In order to achieve the above object, the present invention adopts the following technical solution: A method for preparing a porous carbon-supported metal electrocatalyst comprises the following steps: (1) dissolving a water-soluble carbon source, a metal salt, and a template in water to obtain a precursor solution; (2) spray drying the solution obtained in step (1) to obtain a precursor powder; (3) heating the precursor powder obtained in step (2) to 500-900° C. under a protective atmosphere, keeping the temperature for a period of time, and cooling the precursor powder to room temperature in the furnace; (4) washing and drying the product obtained in step (3) to remove the template residue therein and obtain a porous carbon-supported metal nanoparticle electrocatalyst; Furthermore, the template in (1) includes, but is not limited to, a mixture of one or more template materials that can be uniformly dispersed in water, such as polystyrene beads, polymethyl methacrylate, silica beads, metal organic frameworks, lithium chloride, sodium chloride, potassium chloride, sodium carbonate, etc.
[0008] Furthermore, the carbon source in (1) includes, but is not limited to, a mixture of one or more water-soluble carbon-containing organic molecules such as polyvinyl pyrrolidone, ammonium citrate, glucose, chitosan, and citric acid.
[0009] Furthermore, the metal salt described in (1) includes, but is not limited to, one or a combination of two or more soluble metal salts such as chloroplatinic acid, platinum tetrachloride, potassium chloroplatinate, ammonium chloroplatinate, sodium hexachloroplatinate, ferric nitrate, nickel nitrate, cobalt nitrate, copper nitrate, manganese nitrate, zinc nitrate, silver nitrate, ferric chloride, nickel chloride, cobalt chloride, copper chloride, hydrated ruthenium chloride, manganese chloride, iridium chloride, silver chloride, palladium chloride, etc.
[0010] Furthermore, the molar ratio of the water-soluble carbon source, the metal salt and the water-soluble template in (1) is (0.1-100):(0.1-100):(1-1000), and the mixture is stirred thoroughly to obtain a mixed solution.
[0011] Furthermore, the inert atmosphere in (3) is one or two of helium, argon, nitrogen and hydrogen; and the heating rate during heating is 0.5 to 20°C / min.
[0012] Compared with the prior art, the present invention has the following advantages: (1) the overall process is simple, low-cost, and can be produced continuously; (2) the diversity of metal types and sizes can be increased by changing the type and feed ratio of metal salts, thereby adjusting their catalytic performance; (3) the hydrophilicity and hydrophobicity of carbon can be adjusted by changing the type of carbon source, thereby changing the catalyst to be hydrophilic or hydrophobic. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Figure 1 . Transmission electron microscopy image of the porous carbon-supported PdCu nanoparticle electrocatalyst obtained in Example 1 Figure 2 . X-ray diffraction spectrum of porous carbon-supported PdCu nanoparticle electrocatalyst obtained in Example 1 Figure 3 . Transmission electron microscopy image of the porous carbon-supported metal Pt single-atom electrocatalyst obtained in Example 2 Figure 4 . X-ray diffraction spectrum of porous carbon-supported metal Pt single-atom electrocatalyst obtained in Example 2 Figure 5 . Test results of the electrocatalytic hydrogen evolution reaction of a porous carbon-supported metal Pt single-atom electrocatalyst obtained in Example 2 in 1.0 M potassium hydroxide electrolyte DETAILED DESCRIPTION
[0014] The present invention will be further described below in conjunction with examples. These examples are only used to illustrate the present invention and are not intended to limit the present invention. Embodiment 1
[0015] Ammonium citrate, palladium chloride, copper chloride and sodium chloride were dissolved in water at a molar ratio of 1:0.03:0.97:100 (C:Pd:Cu:NaCl), and stirred thoroughly to obtain a transparent solution. The solution was spray dried to obtain a precursor. The above three-dimensional porous carbon precursor was placed in a nitrogen atmosphere tube furnace, heated to 750°C at 10°C / min, kept warm for 2h, and cooled to room temperature with the furnace. The calcined product was dispersed in water and washed three times to remove the template sodium chloride therein, and dried to obtain a three-dimensional porous carbon-supported PdCu nanoparticle electrocatalyst.
[0016] Instructions attached Figure 1 This is a transmission electron microscope image of the catalyst prepared in this example. It can be seen that PdCu nanoparticles are loaded on the surface of the porous carbon material, and the particle size is about 100 nm. Figure 2 1 is an X-ray diffraction spectrum of the porous carbon-supported PdCu nanoparticle electrocatalyst with different Pd:Cu ratios obtained in Example 1. It can be seen that when the Pd:Cu ratio is 0.03:0.97, the position of the diffraction peak is consistent with that of Cu. Embodiment 2
[0017] Dopamine hydrochloride, chloroplatinic acid and sodium chloride were dissolved in water at a molar ratio of (C:Pt:NaCl) of 1:0.1:100, and stirred thoroughly to obtain a uniform and transparent solution. The solution was spray dried to obtain a precursor. The above three-dimensional porous carbon precursor was placed in an argon atmosphere tube furnace, heated to 750°C at 10°C / min, kept warm for 2h, and cooled to room temperature with the furnace. The calcined product was dispersed in water and washed three times to remove the template sodium chloride therein, and dried to obtain a three-dimensional porous carbon-supported metal Pt single-atom electrocatalyst.
[0018] Instructions attached Figure 3 This is a high-angle annular dark field scanning transmission electron microscope image of the catalyst prepared in this example. It can be seen that a single metal Pt atom is loaded on the surface of the carbon material. Figure 4The powder X-ray diffraction spectrum of the catalyst prepared in this example shows that there is only a carbon peak in the spectrum, and no metal Pt peak is found. Figure 5 The linear sweep voltammetric curve of the electrocatalytic hydrogen evolution performance test of the catalyst prepared in this example in 1.0 mol / L potassium hydroxide solution shows that the current density is 10 mA / cm 2 The overpotential is only 42 mV. Embodiment 3
[0019] Ammonium citrate, chloroplatinic acid, ferric chloride, cobalt chloride, copper chloride, iridium chloride and sodium chloride were dissolved in water at a molar ratio of (C:Pt:Fe:Co:Cu:Ir:Na) of 1:0.2:0.2:0.2:0.2:0.2:100, and stirred thoroughly to obtain a uniform and transparent solution. The solution was spray dried to obtain a precursor. The above three-dimensional porous carbon precursor was placed in a tubular furnace with a hydrogen-argon mixed atmosphere, heated to 800°C at 10°C / min, kept warm for 2h, and cooled to room temperature with the furnace. The calcined product was dispersed in water and washed three times to remove the template sodium chloride therein, and dried to obtain a three-dimensional porous carbon-supported PtFeCoCuIr high entropy alloy nanoparticle electrocatalyst.
Claims
1. A method for preparing a porous carbon-supported metal electrocatalyst, comprising the following steps: (1) dissolving a water-soluble carbon source, a metal salt, and a template in water to obtain a precursor solution; (2) spray drying the solution obtained in step (1) to obtain a precursor powder; (3) heating the precursor powder obtained in step (2) to 500-900° C. under a protective atmosphere, keeping the temperature for a period of time, and cooling the precursor powder to room temperature in the furnace; (4) The product obtained in step (3) is washed with water and dried to remove the template residue therein, thereby obtaining a porous carbon-supported metal electrocatalyst.
2. The preparation method according to claim 1, characterized in that: The template in (1) comprises a mixture of one or more template materials, which can be uniformly dispersed or dissolved in water, including polystyrene beads, polymethyl methacrylate beads, silica beads, metal organic frameworks, lithium chloride, sodium chloride, potassium chloride, and sodium carbonate.
3. The preparation method according to claim 1, characterized in that: (1) The medium carbon source includes a mixture of one or more of water-soluble carbon-containing organic molecules such as polyvinyl pyrrolidone, ammonium citrate, glucose, chitosan, and citric acid.
4. The preparation method according to claim 1, characterized in that: The metal salt described in (1) includes one or a combination of two or more of chloroplatinic acid, platinum tetrachloride, potassium chloroplatinate, ammonium chloroplatinate, sodium hexachloroplatinate, ferric nitrate, nickel nitrate, cobalt nitrate, copper nitrate, manganese nitrate, zinc nitrate, silver nitrate, ferric chloride, nickel chloride, cobalt chloride, copper chloride, ruthenium chloride, manganese chloride, iridium chloride, silver chloride, and palladium chloride.
5. The preparation method according to claim 1, characterized in that: In (1), the molar ratio of the water-soluble carbon source, the metal salt and the template is (0.1-100):(0.1-100):(1-1000), and the mixture is stirred thoroughly to obtain a mixed solution.
6. The preparation method according to claim 1, characterized in that: (3) The atmosphere is one or two of helium, argon, nitrogen and hydrogen; the heating rate during heating is 0.5 to 20°C / min.