Physisorbed, Chemisorbed, and Oxidized CO on Highly Active Cu-CeO2(111)

With the use of the DFT+U method, the properties Of Cu adsorbed oil the stoichiometric CeO2(111) Surface, Cu-doped CeO2(111) (denoted as Cu0.08Ce0.92O2) surface, and CO oxidation oil the stoichiometric Cu0.08Ce0.92O2 Surface are Studied systematically. It is found that (i) Cu is stable both as an adsorbed atom oil the Surface and as dopant in the surface region. Cu adsorbed at the surface is Cu(+I) while Cu as a dopant atom is Cu(+II). (ii) The Cu dopant Facilitates O-vacancy formation considerably, while Cu adsorption on the stoichiometric CeO2(111) surface may suppress oxygen vacancy formation. (iii) Physisorbed CO, physisorbed Coll as well as chemisorbed CO (carbonate) species are observed oil the Cu-doped CeO2(111) surface, in contrast, oil the clean Ceria(111) Surface, only physisorbed CO was previously observed. C-O distances, adsorption energies, and surface-induced C-O vibrational frequency shifts were used to characterize these species.