Investigation of water adsorption and dissociation on Aui/CeO2 single-atom catalysts using density functional theory

We examined the water adsorption and dissociation on ceria surfaces as well as ceria-supported Au single-atom catalysts using density functional theory calculations. Molecular and dissociative water were observed to coexist on clean CeO2 and reduced Aw/CeO2-x, surfaces because of the small difference in adsorption energies, whereas the presence of dissociative water was highly favorable on reduced CeO2-x,and clean Au-1/CeO2 surfaces. Positively charged Au single atoms on the ceria surface not only provided activation sites for water adsorption but also facilitated water dissociation by weakening the intramolecular O-H bonds. In contrast, negatively charged Au single atoms were not reactive for water adsorption because of the saturation of Au 5d and 6s electron shells. This work provides a fundamental understanding of the interaction between water and single-atom Au catalysts. (C) 2017, Dalian Institute of Chemical Physics, Chinese Academy of Sciences.