| In this paper, the solid solution of NH4In1-xGaxS2(x=0,0.1...1) were synthesized by solvothermal method, and we prepared the sulfur compounds of MIn2S4(M=Mn,Fe,Ni,Zn,Cd)by high temperature solid state reaction in vaccum, and we prepared the compounds of MgFe2-xScxO4(x=0.8,0.7,0.6) and Mg1+xFe1+xSc1-2xO4-?(x=0.1,0.2,0.3) by high temperature solid state reaction method. The structure and properties of these compounds have been characterized by X-ray powder diffraction, UV-Vis diffuse reflection and so on. By the way the photocatalytic properties of these materials were characterized by the hydrogen evolution from water reduction(using sacrificial reagents) under visible light irradiation, as well as the photocatalytic nitrate reduction in aqueous solution under ultraviolet light irradiation.(1)In this paper, the solid solution of NH4In1-xGaxS2(x=0,0.1...1) were synthesized by the traditional hydrothermal synthesis of oxalic-acid and thiourea co-molten solvothermal method. The reaction conditions of the blank control test of the nitrate reduction have been optimized,confirming the initial concentration of nitrate was 50 ppm and the sacrificial reagent was the buffer solution of HCOOH-HCOONa(PH=4). After NH4GaS2 and NH4InS2 were employed to catalyze the nitrate reduction in aqueous solution under UV light irradiation, the turned to be Ga2S3 and In2S3.(2)MIn2S4(M=Mn,Fe,Ni,Zn,Cd) were successfully synthesized by high temperature solid state reaction in vacuum. the sacrificial reagents of the nitrate reduction has been confirmed by the use of the 5 catalysts. When it was the buffer solution of HCOOH-HCOONa(PH=4), the result was that the conversion rate of the nitrate reduction with catalysts was equal to the conversion rate of the nitrate reduction with no catalysts; When it was Na2C2O4, the result was that the conversion rate of the nitrate reduction with FeIn2S4 and ZnIn2S4 were twice than the conversion rate of the nitrate reduction with no catalyst and the conversion rate of the nitrate reduction with CdIn2S4 and MnIn2S4 were triple than the conversion rate of the nitrate reduction with no catalyst. Finally we confirmed the Na2C2O4 was the conversion rate of the nitrate reduction.(3) In this paper, MgFe2-xScxO4(x=0.8,0.7,0.6) were synthesized by high temperature solid state reaction. Effectively controlled the band gap of MgFe2-xScxO4(x=0.8,0.7,0.6) by doping varying quantities of the scandium, by the way it can effectively influence the hydrogen evolution activity of the catalyst. The photocatalytic efficiency of MgFe1.2Sc0.8O4 on the H2 evolution from water reduction under Xe-lamp irradiation was 1.5 ?mol/h/g using 4% VOL triethanolamine-H2 O as electronic sacrificial reagents, while the MgFe1.3Sc0.7O4 and MgFe1.4Sc0.6O4 show a H2 production rate of 3.2 ?mol//h/g and 4.7 ?mol//h/g under the same conditions. The experiment result shows that the hydrogen evolution activity of the catalyst under visible light irradiation decreased with the increasing quantity of doping scandium. The photocatalytic efficiency of MgFe1.4Sc0.6O4 which performed best on the H2 evolution from water reduction improved 9.1 ?mol//h/g by loading Pd with chemical reduction method.(4) Similary Mg1+xFe1+xSc1-2xO4-?(x=0.1,0.2,0.3) were synthesized by high temperature solid state reaction. The Eg of the catalyst, which controlled by doping scandium, decreased with the increasing quantity of doping scandium, while the ability of the hydrogen evolution activity of the catalyst under visible light irradiation is enhanced. By the way it maybe relate to the catalyst with oxygen vacancies. The highest hydrogen evolution rate of Mg1.1Fe1.1Sc0.8O4-? was 5.6 ?mol/h/g. And then, we load Pd,Pt,Ru,Ag,Au by chemical reduction method, the Ru- Mg1.1Fe1.1Sc0.8O4-? has the highest evolution rate-13.15?mol/h/g, the Au-Mg1.1Fe1.1Sc0.8O4-? has lowest hydrogen evolution rate-8.45?mol/h/g. These Mg1.1Fe1.1Sc0.8O4-? was employed to catalyze the nitrate reduction in aqueous solution under UV light irradiation, and it show substantial activities. For instance, the conversion rate of the nitrate reduction in 2.5 hours is about 100% by improving experimental facility, where the initial concentration is 50 ppm N... |
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