Formation of Low Work Function Patches in the NO + H2 Reaction on a Roughened Rh(110) Surface
||Electron microscopy, Hydrogen, Nitrogen oxides, Rhodium, Surface chemical reaction
lnstitut fur Physikalische Chemie und Elektroehemie, Universitat Hannover, Callinstr. 3 3a, D-30167 Hannover, Germany
Boreskov Institute of Catalysis
Chemical wave patterns in the NO + H2 reaction on Rh(110) have been investigated on a surface roughened by Ar+ ion sputtering (4 keV, exposure 1016 ions/cm2). The study has been conducted in the 10−6–10−5 mbar range employing photoemission electron microscopy (PEEM) as a spatially resolving method. While the formation of rectangularly and elliptically shaped target patterns is not notably influenced by the roughness produced by sputtering, patches with reduced work functions develop on the surface upon collision of wave fronts. We attribute these patches, which are absent on a smooth Rh(110) surface, to a subsurface oxygen species whose formation is facilitated by structural defects on the surface.