Investigation of multiple commercial electrocatalysts and electrocatalyst degradation for fuel cells in real vehicles

• Published in: RSC advances 2022-11, Vol.12 (5), p.32374-32382
• Main Authors: He, Wenhui, Xiang, Yanjuan, Xin, Mudi, Qiu, Limei, Dong, Wenyan, Zhao, Wenhui, Diao, Yuxia, Zheng, Aiguo, Xu, Guangtong
• Format: Article
• Language: English
• Subjects: Automobiles; Carbon; Catalysis; Catalysts; Cathodes; Chemistry; Commercialization; Degradation; Electrocatalysts; End users; Fuel cells; Interface reactions; Nanoparticles; Photoelectrons; Proton exchange membrane fuel cells; Spectrum analysis; Transmission electron microscopy; X ray photoelectron spectroscopy
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/d2ra05682h

Proton exchange membrane fuel cells (PEMFCs) are regarded as one of the promising new carbon mitigation strategies to realize carbon neutrality. However, efficient and robust electrocatalysts are vital for the commercialization of PEMFCs. Herein, three commercial Pt/C electrocatalysts were investigated including a carbon support and Pt nanoparticles (NPs) to identify their merits and disadvantages, which will help end users quickly select catalysts with excellent performances among the many brands of domestic and foreign catalysts to further better study and better utilize them. Subsequently, they were optimized for real automotive application for about 1800 h, and then the variations in the electrocatalysts on the MEA were analysed by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The mean Pt particle size of the catalysts after operating for 1800 h (cathode, 9.9 ± 3.2 nm) was nearly 4-fold that before use (2.5 ± 0.6 nm), greatly reducing the exposure of metal sites, which was due to the violent three-phase interfacial reaction (ORR) occurring at the cathode side. Also, this assertion was supported by the negative shift in the Pt 4f peaks in the XPS spectra. Moreover, to determine the coalescent evolution of the Pt particles, an in situ TEM experiment was performed. This allowed us to perform fundamental Pt NP degradation studies on the carbon support, which can result in an improvement in the sustainability of catalysis. The coalescence of Pt nanoparticles during operation in a real vehicle is considered to be the main reason to weaken the ORR. The trajectories of oriented attachment were disclosed by observing the coalescence events of Pt NPs using in situ TEM.