title: Structurally ordered intermetallic platinum-cobalt core-shell nanoparticles with enhanced activity and stability as oxygen reduction electrocatalysts.
abstract: To enhance and optimize nanocatalyst performance and durability for the oxygen reduction reaction in fuel-cell applications, we look beyond Pt-metal disordered alloys and describe a new class of Pt-Co nanocatalysts composed of ordered Pt(3)Co intermetallic cores with a 2-3 atomic-layer-thick platinum shell. These nanocatalysts exhibited over 200% increase in mass activity and over 300% increase in specific activity when compared with the disordered Pt(3)Co alloy nanoparticles as well as Pt/C. So far, this mass activity for the oxygen reduction reaction is the highest among the Pt-Co systems reported in the literature under similar testing conditions. Stability tests showed a minimal loss of activity after 5,000 potential cycles and the ordered core-shell structure was maintained virtually intact, as established by atomic-scale elemental mapping. The high activity and stability are attributed to the Pt-rich shell and the stable intermetallic Pt(3)Co core arrangement. These ordered nanoparticles provide a new direction for catalyst performance optimization for next-generation fuel cells.
authors.affiliation: Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, USA.
authors.forename: Deli
authors.initials: D
authors.lastname: Wang
authors.forename: Huolin L
authors.initials: HL
authors.lastname: Xin
authors.forename: Robert
authors.initials: R
authors.lastname: Hovden
authors.forename: Hongsen
authors.initials: H
authors.lastname: Wang
authors.forename: Yingchao
authors.initials: Y
authors.lastname: Yu
authors.forename: David A
authors.initials: DA
authors.lastname: Muller
authors.forename: Francis J
authors.initials: FJ
authors.lastname: DiSalvo
authors.forename: Héctor D
authors.initials: HD
authors.lastname: Abruña