Electrochemically Identifying Degradation Pathways of Carbon-Supported Pt Catalysts Assists in Designing Highly Durable Catalysts

Supported Pt catalysts are considered highly efficient in many applications because of their unique catalytic properties. Their poor durability hampers their use in practical applications, particularly in novel energy-conversion devices such as fuel cells. A facile electrochemical procedure that combines the evaluation of the electrochemical surface area with a breakthrough in direct electrochemical quantification of the Pt content was utilized. Catalytic performance-related factors and kinetics of Pt nanoparticle (Pt nano ) growth on a carbon substrate were probed under high-temperature annealing and ambient-temperature potential polarization, respectively. Apart from the Pt dissolution/redeposition pathway, we demonstrated that the crystal migration/coalescence pathway in catalyst degradation could not be ignored at ambient temperature. We report the enhanced durability and long-term activity of carbon-supported Pt catalysts, where the Pt nano surface was partially encapsulated by nonspecific noble metal clusters; inhibition of the migration/coalescence pathway and effective exposure of Pt nano surface active sites led to such enhancements.