Role of vacancies, light elements and rare-earth metals doping in CeO2

The magnetic properties and electronic structures of pure, doped and defective cerium oxide (CeO₂) have been studied theoretically by means of ab initio calculations based on the density function theory (DFT) with the hybrid HF/DFT technique named PBE0. Carbon (C), nitrogen (N), phosphorus (P), sulphur (S), lanthanum (La) and praseodymium (Pr) doped in CeO₂ and CeO₂ containing oxygen vacancies (O_v) were considered. Our spin-polarized calculations show that C, N, Pr dopants and O_v defects magnetize the non-magnetic CeO₂ in different degree. The optical band gap related to photocatalysis for pure CeO₂, corresponding to the ultraviolet region, is reduced obviously by C, N, S, Pr impurities and oxygen vacancies, shifting to the visible region and even further to the infrared range. Especially, N-, S- and Pr-doped CeO₂ could be used to photocatalytic water splitting for hydrogen production. As the concentration of O_v increasing up to 5%, the CeO₂ exhibits a half-metallic properties.