Influence of the alumina surface orientation to the Rh particle growth and reconstruction

Growth and reconstruction of Rh particles deposited onto different Al2O3 substrates were studied. Three single crystalline α-alumina substrates, having (0 0 0 1), (1 1̄ 0 2) and (1 1 2̄ 0) surface orientations, and polycrystalline γ-alumina were positioned simultaneously on the same sample holder. Consequently, all performed procedures (Rh deposition, sample annealing, CO and O2 adsorption) were completely identical. mple conditions were checked after every particular procedure by means of electron spectroscopy, especially AES and EPES. Morphology parameters (Rh particle size and density) of Rh deposit were measured ex situ using transmission electron microscopy of the sample carbon replica. The difference among the electron spectra obtained on the identically treated samples is discussed to study the influence of the substrate orientation on the properties of Rh/Al2O3 model catalysts.