title: Palladium-platinum core-shell icosahedra with substantially enhanced activity and durability towards oxygen reduction.
abstract: Conformal deposition of platinum as ultrathin shells on facet-controlled palladium nanocrystals offers a great opportunity to enhance the catalytic performance while reducing its loading. Here we report such a system based on palladium icosahedra. Owing to lateral confinement imposed by twin boundaries and thus vertical relaxation only, the platinum overlayers evolve into a corrugated structure under compressive strain. For the core-shell nanocrystals with an average of 2.7 platinum overlayers, their specific and platinum mass activities towards oxygen reduction are enhanced by eight- and sevenfold, respectively, relative to a commercial catalyst. Density functional theory calculations indicate that the enhancement can be attributed to the weakened binding of hydroxyl to the compressed platinum surface supported on palladium. After 10,000 testing cycles, the mass activity of the core-shell nanocrystals is still four times higher than the commercial catalyst. These results demonstrate an effective approach to the development of electrocatalysts with greatly enhanced activity and durability.
authors.affiliation: 1] Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332, USA [2] State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, Xiamen University, Xiamen, Fujian 361005, China [3] Department of Chemistry, Xiamen University, Xiamen, Fujian 361005, China.
authors.forename: Xue
authors.initials: X
authors.lastname: Wang
authors.affiliation: Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332, USA.
authors.forename: Sang-Il
authors.initials: SI
authors.lastname: Choi
authors.affiliation: Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
authors.forename: Luke T
authors.initials: LT
authors.lastname: Roling
authors.affiliation: Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332, USA.
authors.forename: Ming
authors.initials: M
authors.lastname: Luo
authors.affiliation: Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: Cheng
authors.initials: C
authors.lastname: Ma
authors.affiliation: 1] Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332, USA [2] State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, Xiamen University, Xiamen, Fujian 361005, China [3] Department of Chemistry, Xiamen University, Xiamen, Fujian 361005, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: Miaofang
authors.initials: M
authors.lastname: Chi
authors.affiliation: Department of Physics, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: Jingyue
authors.initials: J
authors.lastname: Liu
authors.affiliation: 1] State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, Xiamen University, Xiamen, Fujian 361005, China [2] Department of Chemistry, Xiamen University, Xiamen, Fujian 361005, China.
authors.forename: Zhaoxiong
authors.initials: Z
authors.lastname: Xie
authors.affiliation: Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Herron
authors.affiliation: Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
authors.forename: Manos
authors.initials: M
authors.lastname: Mavrikakis
authors.affiliation: 1] Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332, USA [2] School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, USA [3] School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
authors.forename: Younan
authors.initials: Y
authors.lastname: Xia