Metastable impact electron emission microscopy of the catalytic H2 oxidation on Rh(110)

Laterally resolved metastable impact electron spectroscopy is based on the energy analysis of electrons originating from collisions of metastable He* (2S) atoms with the surface, and can be used for probing the spatial distribution of surface species, i.e. for chemically resolved surface microscopy ðMIEEM 1⁄4 metastable impact electron emission microscopyÞ. We report upon first MIEEM results on the spectroscopic imaging of the catalytic H2 oxidation on the clean and potassium-precovered Rh(1 1 0) surface, in which the spatio-temporal distribution of the reactants on the surface, the reaction fronts as well as the redistribution of the initially spatially homogeneous K coverage have been monitored. The results are in agreement with data previously obtained by scanning photoelectron microscopy and are discussed in terms of self-organization in the diffusion zone. 2003 Elsevier Science B.V. All rights reserved.