Design of Cu-Ce co-doped TiO for improved photocatalysis.

The fast recombination of photo-generated conduction band electrons ( e ) and valance band holes ( h ) of TiO results in an unsatisfactory photocatalytic performance for organic degradation. To increase the efficiency of charge separation, TiO was modified by Cu-Ce co-doping considering the better redox properties of copper-ceria oxide with respect to the single oxide, i.e., an easier electron capturing ability. An optimal Cu-Ce co-doped TiO with the initial molar ratio of Cu/Ce at 3:1 was prepared by a hydrothermal method with the aim to greatly promote the charge separation, and characterized by XRD, BET, DRS, PL, HR-TEM, and XPS techniques. Upon ultraviolet light irradiation, it exhibits significantly enhanced photocatalytic activity, about 5.8 times that of Ti-HF. The presence of Cu and Ce/Ce benefits electrons captured by molecular oxygen, while an increased hydroxyl groups upon Cu-Ce co-doping consume more holes, resulting in prolonged lifetime of photo-generated carriers. Moreover, it is proved that electron transfers preferably from conduction band (CB) of TiO to CB of CuO and then to nearby CeO. [ABSTRACT FROM AUTHOR]