A kind of preparation method and application of graphene-coated metal nanoparticle catalyst

Abstract

The invention relates to a preparation method for a graphene-coated iron-loaded and nitrogen-loaded active site catalyst on a carbon nano tube (CNT); sources of raw materials used for the method are extensive; carbon source and nitrogen source materials are low in cost; the sample yield is high; the production cost of a fuel cell is helped to be reduced; the content of Fe and N in the prepared catalyst is controllable, and meanwhile, bigger specific surface area is kept so as to overcome the problem that metal nanometer particles are easy to aggregate in the past. The preparation method comprises the following steps: (1) supporting Fe and N to the surface of the carbon nano tube to obtain Fe-N-CNT; (2) synthetizing a composite material, formed by coating the surface of the Fe-N-CNT with graphene precursors, by a hydrothermal method; (3) calcining the composite material to obtain Fe-N-CNT&GN. Compared with a traditional fuel cell cathode Pt / C catalyst, the catalyst prepared by the method disclosed by the invention is low in cost, relatively higher in catalytic activity, high in stability, high in methanol tolerance, and has a good commercial application prospect.

Description

technical field [0001] The invention belongs to the technical field of energy materials and electrochemistry, and relates to a preparation method of an electrocatalyst applied to the cathode oxygen reduction reaction of a fuel cell, in particular to a metal nanoparticle catalyst coated with graphene and carried on a carbon nanotube Preparation. Background technique [0002] The depletion of fossil resources and environmental degradation continue to intensify, and the development and utilization of clean and renewable energy has become a global focus. Low-temperature fuel cell is an electrochemical reaction device that directly converts the chemical energy of fuel into electrical energy. It has the characteristics of simple structure, high theoretical energy density, and environmental protection. It has become a research hotspot of scholars at home and abroad in recent years. However, the commercialization of low-temperature fuel cells still faces certain challenges, one of ...

AI Technical Summary

Problems solved by technology

However, the commercialization of low-temperature fuel cells still faces certain challenges, one of which is the slow kinetics of the cathode oxygen reduction (ORR) process.

At present, carbon-supported platinum and platinum alloy catalysts are the best performance and most widely used oxygen reduction catalysts for fuel cells, but Pt-based electrocatalysts are poor in stability and high in price, which limits the large-scale commercialization of fuel cells, so the development has high Catalysts with catalytic activity and stability, corrosion resistance and low cost have important practical significance and application value

[0003] Metal-nitrogen-carbon materials are considered to be the most promising non-precious metal ORR electrocatalysts, but there are still some problems: unreasonable structures or easy agglomeration make metal-nitrogen-carbon materials unevenly dispersed, which limits the catalytic performance. The loading of active metal-nitrogen-carbon materials reduces the overall nitrogen density of the material and reduces the metal utilization rate (generally only 2-5%); the degree of graphitization is low and the conductivity is poor; the small specific surface area makes ORR The mass transfer efficiency is low; more importantly, the active sites of ordinary metal-nitrogen-carbon materials are easily corroded in the electrolyte solution, thereby reducing the catalytic activity and life of the catalyst

However, the preparation method has poor reproducibility, metal nanoparticles are easy to agglomerate, and have poor catalytic performance for ORR.

Images