Low-Energy Electron Diffraction, Auger Electron Spectroscopy and Thermal Desorption Studies of Chemisorbed CO and O2 on the (111) and Stepped (6(111)x(100)) Iridium Surfaces.

摘要

The adsorption of CO, O2 and H2O was studied on both (111) and (6(111)x(100)) crystal faces of iridium. The techniques used are LEED, AES and thermal desorption. Marked differences were found in surface structures and heats of adsorption on these crystal faces. Oxygen is adsorbed in a single bond state on the (111) face. On the stepped iridium surface an additional bonding state with a higher heat of adsorption was detected which can be attributed to oxygen adsorbed at steps. On both (111) and stepped iridium crystal faces the adsorption of oxygen at room temperature produced a (2x1) surface structure. The influence of steps on the adsorption behavior of CO and O2 on iridium and the correlation with the results found previously on the same platinum crystal faces are discussed.