Abstract. Silver doped TiO2 catalyst TiO2-Ag was synthesized by microwave hydrothermal method when the optimal condition was selected with orthogonal and single factor tests. The photocatalytic activity of TiO2-Ag catalyst was further enhanced by the microwave and ultrasonic assisted with using methyl orange as pollutants. And the TiO2-Ag was characterized by the XRD, SEM, EDS, TG-DSC-DTG, BET and ICP-AES. The results showed that the optimal conditions of TiO2-Ag prepared by microwave hydrothermal method was n(Ag+)/n(Ti4+)=0.003, microwave power 600 W, reacting time for 3 h at 140℃ and calcining time for 3 h at 550℃. The TiO2-Ag had higher photocatalytic activity and stability which get better degradation efficiency in a relatively short period of time for the degradation of organic pollutants when the microwave and ultrasonic assisted optimization condition. The structure characterization of the catalyst showed that the microwave hydrothermal synthesis of Ag doped TiO2 photo catalysts had OH multi-surface, high crystallinity and large surface area, and inhibited the phase transformation of TiO2 from anatase to rutile. At the same time, the doped catalyst prepared by microwave hydrothermal process was feasible method with high rate the use of drugs.

The optimum conditions for the preparation of TiO 2-Ag-Sm photocatalysts by microwave hydrothermal method are as follows: n(Ag +): n(Ti 4+)=0.3%, microwave power 600 W, reaction temperature 150 ℃, reaction time 3 h, calcination temperature 650 ℃ and calcination time 3h. The structure of the catalyst was characterized by XRD, SEM-EDS, ICP-AES, UV-Vis, IR and BET. The photocatalytic degradation activity of TiO 2-Ag-Sm catalyst was investigated under the conditions of microwave, ultraviolet, microwave-ultraviolet and microwave-ultrasonic-ultraviolet under methyl orange solution as simulated pollutant. The results showed that methyl orange was almost degraded completely when the methyl-orange solution was degraded by microwave-ultrasonic-ultraviolet irradiation for 25 min.

Abstract-Yb and Er co-doped TiO2 photo-catalysts were synthesized by microwave drying method and sol-gel method with room temperature ionic liquid as a reaction medium. The purpose of the experiment was order to improve the photo-catalytic activity and accelerate the degradation of pollutants, for example methyl orange. The structure and morphology of TiO2-Yb-Er were characterized with XRD, IR and SEM. The photo-catalytic activity was respectively investigated by microwave irradiation (MW) and ultraviolet irradiation (UV) and microwave irradiation with ultraviolet irradiation (MW-UV) with the photo-catalytic degradation of methyl orange solution as simulated pollutants. The results showed that the TiO2-Yb-Er catalysts prepared at the optimum condition had higher photo-catalytic activity.