[Zurück]

D. Vogel, C. Spiel, M. Schmid, M. Stöger-Pollach, R. Schlögl, Y. Suchorski, G. Rupprechter:
"The Role of Defects in the Local Reaction Kinetics of CO Oxidation on Low-Index Pd Surfaces";
Journal of Physical Chemistry C, 117 (2013), S. 12054 - 12060.

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 10−5 mbar
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.