Cathode catalyst layer structure capable of enhancing catalyst durability and preparation method thereof

Abstract

The invention discloses a fuel cell cathode catalyst layer structure capable of enhancing catalyst durability, and relates to the technical field of fuel cells. The fuel cell cathode catalyst layer structure comprises a first catalytic part, a second catalytic part and a third catalytic part which are sequentially arranged in the direction from an area close to a diffusion layer side to an area close to a proton exchange membrane side; pure platinum catalysts are arranged in the first catalytic part, the second catalytic part and the third catalytic part; the platinum loading capacities of thepure platinum catalysts in the first catalytic part, the second catalytic part and the third catalytic part are sequentially decreased; the average particle sizes of the pure platinum catalyst particles in the first catalytic part, the second catalytic part and the third catalytic part are sequentially increased; the large-particle-size pure platinum catalyst is more corrosion-resistant, and thesmall-particle-size pure platinum catalyst improves the initial performance of the fuel cell, so that the loss of the specific surface area of the catalyst under potential scanning is conveniently reduced; and the attenuated cathode catalyst is more uniform in platinum specific surface area and platinum mass distribution, so that the attenuated oxygen and proton mass transfer loss is reduced, theperformance of the attenuated fuel cell is improved, and the durability is improved.

Description

technical field [0001] The invention relates to the technical field of fuel cells, in particular to a cathode catalyst layer structure and a preparation method for enhancing catalyst durability. Background technique [0002] A fuel cell is a chemical device that directly converts the chemical energy of fuel into electrical energy, also known as an electrochemical generator. It is the fourth power generation technology after hydropower, thermal power and atomic power. Since the fuel cell converts the Gibbs free energy in the chemical energy of the fuel into electrical energy through an electrochemical reaction, it is not limited by the Carnot cycle effect, so the efficiency is high; in addition, the fuel cell uses fuel and oxygen as raw materials; at the same time There are no mechanical transmission parts, so there is no noise pollution, and the emission of harmful gases is very small. It can be seen that from the point of view of saving energy and protecting the ecologica...

AI Technical Summary

Problems solved by technology

During the potential cycle process, the platinum catalyst will undergo Oswald ripening, which will eventually lead to an increase in the average particle size of the catalyst and a decrease in the effective specific surface area of ​​the catalyst in the long-term operation, that is, the number of catalytic reaction active sites is reduced, and the At the same time, the platinum ions dissolved at high potential will migrate to the direction of the proton exchange membrane under the action of concentration difference diffusion and electromigration, and then be reduced by hydrogen permeation in the proton exchange membrane, which will lead to Loss of platinum mass and significantly increased catalyst decay near the membrane side, resulting in increased oxygen and proton mass transfer losses within the cathode catalyst layer during long-term operation

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