Research on Performance Decay Mechanism of Pt/C Catalyst in Long-Term ORR Test北大核心CSCD

In proton exchange membrane fuel cells，cost，performance and durability are important issues that are need to be resolved before commercialization. The main reason for fuel cell performance degradation during operation is the loss of electrochemical surface area during long-term aging or transient. These losses mainly come from the degradation of the catalyst metal and the corrosion of the carbon support. This is a continuous and irreversible process that will greatly shorten the service life of the fuel cell. In order to explore this problem，20%（mass fraction）Pt/C catalyst is prepared based on carbon carrier etched by sulfuric acid. The morphology characterization test shows that it is uniformly dispersed and uniform in particle size，which is considered as an excellent material for long-term oxygen reduction （ORR） stability test. Next，the ORR stability test method with different cyclic voltammetry （CV） cycles is used to observe its performance degradation，and a series of physical characterizations，e. g. transmission electron microscopy（TEM），high-resolution electron microscopy（HRTEM），X-ray photoelectron spectroscopy（XPS）and Raman spectroscopy （Raman），are used to further intuitively analyzed the attenuation mechanism. It is reported that the reasons for the degradation of the stability of Pt/C catalysts are mainly from the dissolution，agglomeration，oxidation and migration of Pt particles and the corrosion of carbon supports. This study elucidates the source of the impact on the stability of fuel cells during operation，and provides a reference for designing high-stability commercial ORR catalysts. © 2022, Science Press (China). All rights reserved.