Abs~aaIn this paper the results of the partial oxidation of methane over Ni-based and Co-based catalysts activated by two different heating modes (conventional and microwaves) are reported. Compared with a conventional heating mode, the temperature of the catalytic bed is much lower and there is a higher selectivity of CO and H2 with microwave irradiation.

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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.

Abstract. Samarium doped TiO2 photocatalyst TiO2-Sm was prepared by microwave hydrothermal method using Samarium nitrate and tetrabutyl titanate as raw materials. Degradation of methyl orange was used to photocatalytic reaction of TiO2-Sm respectively under the conditions of visible light, microwave (MW), ultraviolet (UV), ultraviolet microwave (UV-MW) and ultraviolet microwave ultrasonic (UV-MW-UT). The TiO2-Ag was characterized by SEM, TG-DSC-DTG, IR and UV-Vis. The results showed that the optimal conditions of TiO2-Sm prepared by microwave hydrothermal method was n(Sm3+)/n(Ti4+)=0.003, microwave power 450 W, reacting time for 3 h at 170℃ and calcining time for 3 h at 700℃. The degradation rate was 11.51%, 96.83%, 99.5% and 100% respectively by MW, UV, UV-MW and UV-MW-UT for 35 min degradation. Sm doped had great influence on the crystal formation which widen the temperature range of catalyst from amorphous to anatase and suppressing the anatase structure into rutile structure. Moreover Sm doped produced more hydroxyl groups and could also widen the absorb range of ultraviolet and visible light which caused the enhancement of the photocatalytic activity of TiO2-Sm.

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.