title: Design principles for oxygen-reduction activity on perovskite oxide catalysts for fuel cells and metal-air batteries.
abstract: The prohibitive cost and scarcity of the noble-metal catalysts needed for catalysing the oxygen reduction reaction (ORR) in fuel cells and metal-air batteries limit the commercialization of these clean-energy technologies. Identifying a catalyst design principle that links material properties to the catalytic activity can accelerate the search for highly active and abundant transition-metal-oxide catalysts to replace platinum. Here, we demonstrate that the ORR activity for oxide catalysts primarily correlates to σ-orbital (e(g)) occupation and the extent of B-site transition-metal-oxygen covalency, which serves as a secondary activity descriptor. Our findings reflect the critical influences of the σ orbital and metal-oxygen covalency on the competition between O(2)(2-)/OH(-) displacement and OH(-) regeneration on surface transition-metal ions as the rate-limiting steps of the ORR, and thus highlight the importance of electronic structure in controlling oxide catalytic activity.
authors.affiliation: Materials Science and Engineering Department and Electrochemical Energy Laboratory, Massachusetts Institute of Technology, 31-056, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
authors.forename: Jin
authors.initials: J
authors.lastname: Suntivich
authors.forename: Hubert A
authors.initials: HA
authors.lastname: Gasteiger
authors.forename: Naoaki
authors.initials: N
authors.lastname: Yabuuchi
authors.forename: Haruyuki
authors.initials: H
authors.lastname: Nakanishi
authors.forename: John B
authors.initials: JB
authors.lastname: Goodenough
authors.forename: Yang
authors.initials: Y
authors.lastname: Shao-Horn