Electronic storage capacity of ceria: role of peroxide in Aux supported on CeO2(111) facet and CO adsorption

Abstract

Density functional theory (DFT+U) was used to study the adsorption of Au_x (x = 1–4) clusters on the defective CeO₂(111) facet and CO adsorption on the corresponding Au_x/CeO_2−x catalyst, in this work Au_x clusters are adsorbed onto the CeO_2−x + superoxide/peroxide surface. When Au₁ is supported on the CeO₂(111) facet with an O vacancy, the strong electronegative Au^δ− formed is not favorable for CO adsorption. When peroxide is adsorbed on the CeO₂(111) facet with the O vacancy, Au_x was oxidized, resulting in stable Au_x adsorption on the defective ceria surface with peroxide, which promotes CO adsorption on the Au_x/CeO_2−x catalyst. With more Au atoms in supported Au_x clusters, CO adsorption on this surface becomes stronger. During both the Au being supported on CeO_2−x and CO being adsorbed on Au_x/CeO_2−x, CeO₂ acts as an electron buffer that can store/release the electrons. These results provide a scientific understanding for the development of high-performance rare earth catalytic materials.