SIZE EFFECT STUDY OF CARBON-MONOXIDE OXIDATION BY RH SURFACES

The catalytic oxidation of CO on Rh foil and small Rh particles suppor ted by Al2O3 polycrystalline surfaces was studied by the transient exp eriment of molecular beam surface scattering technique. The supported Rh particles were prepared by evaporation, using the principle of elec tron bombardment, The results show the dependence of the CO2 productio n rate on surface morphology and particle size. The defect rich Rh foi l 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 d iffusion into the subsurface region.