Theoretical Investigations of Pt1@CeO2 Single-Atom Catalyst for CO Oxidation

In the present study, we perform systematic density functional investigations on the single-atom Pt catalysts dispersed on CeO 2 (111), (110), and (100) surfaces. The structural and electronic properties of these SACs and their corresponding catalytic activity for CO oxidation are discussed. It is shown that the single-atom Pt substitution of a lattice Ce ion is thermodynamically stable on each ceria surface. On the (111) and (100) surfaces, the single Pt atom is found to exist at an oxidation state of +4 upon replacement of Ce 4+, while, on the (110) surface, it exhibits a planar structure with a reduced oxidation state of +2 due to the spontaneous formation of surface peroxide O 2 2– species. On all of the surfaces, CO oxidation is found to follow the Mars–van Krevelen mechanism. It is the single-atom Pt, rather than the lattice Ce, that acts as the electron acceptor/donor in the redox processes during the whole catalytic cycle. This work provides insights on the significant role of a single metal atom on reducible oxide of ceria and others.