Abstract: In the present work, the influence of silver deposition on the transfer of photogenerated electrons was investigated. The catalyst was characterized by in-situ EPR, DRS, BET and phenol degradation under different conditions. The result showed that suitable size of silver cluster deposition can attract photogenerated electrons effectively and then the electrons transferred to the adsorbed oxygen and surface Ti4＋ efficiently. The recombination of the photogenerated electrons and holes was inhibited. The enhanced photocatalytic activity was mainly caused by the increased amount of reactive species, the higher amount of surface reactive center Ti3＋ and photogenerated holes.

Key words: Nano-size silver cluster, Ag/TiO₂, Electron transfer, Photocatalysis, 　In-situ EPR