Switching The Type Of Redox Activity Of Colloidal Nanoceria By Re3+ (Re = Y, Eu, Tb) Doping

Nanoceria (CeO2-x) is well-known for its enzyme-like antioxidant activity determined by Ce3+<-> Ce4+ redox cycles on the surface of nanoparticle during interaction with reactive oxygen species. We show the crucial role of the surface defect structure in the mechanisms of interaction of Re3+ (Re = Y, Eu, Tb) doped nanoceria with hydrogen peroxide (HP) and hydroxyl radicals ((OH)-O-center dot). Both catalase-like (for CeO2:Tb3+) and Fenton-like (for CeO2:Y3+ and CeO2:Eu3+) HP decomposition was observed for Re3+-doped ceria nanoparticles leading to antioxidant or prooxidant activity, respectively. Overall, the type of Re3+ ion determines the mechanism and efficiency of redox activity of nanoceria.