Direct observation of reaction-induced lateral redistribution of sub-monolayers of Au deposited on a Rh(1 1 0) surface

X-ray photoemission electron microscopy (XPEEM), combined with micro-low energy electron diffraction (LEED) and low energy electron microscopy (LEEM) were employed to study the dynamic changes occurring during the H2 + O2 reaction on a Rh(1 1 0) surface covered with a submonolayer of Au. It was found that the propagating reduction/oxidation fronts destroy the lateral homogeneity of the Au adlayer resulting in the development of a “patterned” interface consisting of Au-depleted and Au-enriched areas. The evolution of this reaction-induced morphologically complex interface was examined by varying the reaction conditions, in order to verify the mechanism of the observed Au mass transfer processes. The Au-patterned surface is preserved in oxidation ambient but is rapidly destroyed during reduction.