Size effect study of carbon monoxide oxidation by Rh surfaces

The catalytic oxidation of CO on Rh foil and small Rh particles supported by Al2O3 polycrystalline surfaces was studied by the transient experiment of molecular beam surface scattering technique. The supported Rh particles were prepared by evaporation, using the principle of electron bombardment, The results show the dependence of the CO2 production rate on surface morphology and particle size. The defect rich Rh foil surface and smaller particles were found to be more active. The high oxygen adsorption capacity of 2.5 nm particles as well as their time dependent form of the CO2 production rate is explained by the oxygen diffusion into the subsurface region.