INTERACTION OF CARBON-DIOXIDE WITH CLEAN AND OXYGENATED CU(110) SURFACES

Thermal desorption studies of CO2 adsorbed on Cu(110) at 85 K and low pressures reveal nearly 100% dissociation on the oxygen-free surface to give adsorbed oxygen and CO. By oxygen predosing a pronounced molecular adsorption state at 100 K is induced with up to a twenty-fold coverage increase, which cannot be explained by simply considering the dissociation equilibrium on the surface. Probably new sites are generated by oxygen as indicated by a pronounced increase of the sticking coefficient. The adsorbed amount of CO2 in dependence on oxygen dose at 85 K exhibits a maximum, which is tentatively attributed to the dynamics of the surface due to oxygen induced reconstruction ((1 x 1) --> p(2 x 1)). On polycrystalline copper enhanced CO2 dissociation is observed.