Pt-Co@Pt Octahedral Nanocrystals: Enhancing Their Activity and Durability toward Oxygen Reduction with an Intermetallic Core and an Ultrathin Shell

Despite extensive efforts devoted to the synthesis of Pt-Co bimetallic nanocrystals for fuel cell and related applications, it remains a challenge to simultaneously control atomic arrangements in the bulk and on the surface. Here we report a synthesis of Pt-Co@Pt octahedral nanocrystals that feature an intermetallic, face-centered tetragonal Pt-Co core and an ultrathin Pt shell, together with the dominance of {111} facets on the surface. When evaluated as a catalyst toward the oxygen reduction reaction (ORR), the nanocrystals delivered a mass activity of 2.82 A mg(-1) and a specific activity of 9.16 mA cm(-2), which were enhanced by 13.4 and 29.5 times, respectively, relative to the values of a commercial Pt/C catalyst. More significantly, the mass activity of the nanocrystals only dropped 21% after undergoing 30 000 cycles of accelerated durability test, promising an outstanding catalyst with optimal performance for ORR and related reactions.

Automated summary

In this study, Pt-Co@Pt octahedral nanocrystals were successfully synthesized with an intermetallic Pt-Co core and an ultrathin Pt shell dominated by {111} facets on the surface. These nanocrystals showed significantly improved catalytic performance towards the oxygen reduction reaction compared to a commercial Pt/C catalyst, with a mass activity 13.4 times higher and a specific activity 29.5 times higher. Importantly, the mass activity of the nanocrystals only decreased by 21% after 30,000 cycles of accelerated durability testing, indicating their outstanding potential as catalysts for ORR and related reactions.