title: The Role of Defects in the Local Reaction Kinetics of CO Oxidation on Low-Index Pd Surfaces.
abstract: The role of artificially created defects and steps in the local reaction kinetics of CO oxidation on the individual domains of a polycrystalline Pd foil was studied by photoemission electron microscopy (PEEM), mass spectroscopy (MS), and scanning tunneling microscopy (STM). The defects and steps were created by STM-controlled Ar+sputtering and the novel PEEM-based approach allowed the simultaneous determination of local kinetic phase transitions on differently oriented μm-sized grains of a polycrystalline sample. The independent (single-crystal-like) reaction behavior of the individual Pd(hkl) domains in the 10-5mbar pressure range changes upon Ar+sputtering to a correlated reaction behavior, and the reaction fronts propagate unhindered across the grain boundaries. The defect-rich surface shows also a significantly higher CO tolerance as reflected by the shift of both the global (MS-measured) and the local (PEEM-measured) kinetic diagrams toward higher CO pressure.
authors.affiliation: Institute of Materials Chemistry, Institute of Applied Physics, and University Service Center for Transmission Electron Microscopy, Vienna University of Technology , Vienna, Austria ; Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Vogel
authors.forename: C
authors.initials: C
authors.lastname: Spiel
authors.forename: M
authors.initials: M
authors.lastname: Schmid
authors.forename: M
authors.initials: M
authors.lastname: Stöger-Pollach
authors.forename: R
authors.initials: R
authors.lastname: Schlögl
authors.forename: Y
authors.initials: Y
authors.lastname: Suchorski
authors.forename: G
authors.initials: G
authors.lastname: Rupprechter