Study of CO adsorption on Rh/alumina model catalysts in dependence on substrate orientation

The interaction of a CO molecular beam with rhodium vapour-deposited onto (0001), (1–102) and (11–20) α-alumina was investigated. The dependence of the CO sticking coefficient on the sample temperature and the relative CO coverage for different Rh deposits were calculated from the intensity of the reflected CO molecular beam. The diffusion of CO over the uncovered substrate to the metal is discussed in relation to the Rh particle size and density.