title: Dynamic structural evolution of supported palladium-ceria core-shell catalysts revealed by in situ electron microscopy.
abstract: The exceptional activity for methane combustion of modular palladium-ceria core-shell subunits on silicon-functionalized alumina that was recently reported has created renewed interest in the potential of core-shell structures as catalysts. Here we report on our use of advanced ex situ and in situ electron microscopy with atomic resolution to show that the modular palladium-ceria core-shell subunits undergo structural evolution over a wide temperature range. In situ observations performed in an atmospheric gas cell within this temperature range provide real-time evidence that the palladium and ceria nanoparticle constituents of the palladium-ceria core-shell participate in a dynamical process that leads to the formation of an unanticipated structure comprised of an intimate mixture of palladium, cerium, silicon and oxygen, with very high dispersion. This finding may open new perspectives about the origin of the activity of this catalyst.
authors.affiliation: Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136, USA.|Department of Chemical Engineering and Materials Science, University of California-Irvine, Irvine, California 92697, USA.
authors.forename: Shuyi
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Chen
authors.initials: C
authors.lastname: Chen
authors.affiliation: Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Matteo
authors.initials: M
authors.lastname: Cargnello
authors.affiliation: Department of Chemical and Pharmaceutical Sciences, ICCOM-CNR Trieste Research Unit and INSTM, University of Trieste, 34127 Trieste, Italy.
authors.forename: Paolo
authors.identifier: http://orcid.org/0000-0003-1082-9157
authors.initials: P
authors.lastname: Fornasiero
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Raymond J
authors.initials: RJ
authors.lastname: Gorte
authors.affiliation: Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136, USA.
authors.forename: George W
authors.initials: GW
authors.lastname: Graham
authors.affiliation: Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136, USA.|Department of Chemical Engineering and Materials Science, University of California-Irvine, Irvine, California 92697, USA.|Department of Physics and Astronomy, University of California-Irvine, Irvine, California 92697, USA.
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Pan