Precious Metal Modified TiO ₂ / SiO ₂ / ₃ O _{Preparation And Photocatalytic Fe 4} Composite Oxide Research Performance

For improve the catalytic activity under visible light and The catalyst recyclingabout the TiO2. base on composite photocatalyst TiO2/SiO2/Fe3O4could be recycle withmagnetism, and modified photocatalyst with noble metal which could Improve thecatalytic activity under visible light was prepared also in this paper. The structures andchemical properties of the prepared samples were characterized by XRD, FT-IR, SEM.By adjusted the doping amount of preparative conditions, study the effects of thecatalysts’ morphology，structure with different preparation conditions. And prepared thenoble metal modified TiO2/SiO2/Fe3O4composite with well performance. Andpreliminary discussed the mechanism.Fe3O4magnetic core was prepared by the hydrothermal method, and middle layercoating of SiO2prepared by st ber method,and outermost layer coating of TiO2wereprepared by sol-gel method in this experiment. The prepared sample was characterizedby XRD, SEM, and VSM, the results showed that the particle size of Fe3O4was at about200nm, SiO2middle layer exist in anatase phase, and the mean particle size was about400nm. They were magnetic homogenrous sphere and the crystal shape were complete.Ag-TiO2/SiO2/Fe3O4photocatalyst was prepared with sol-gel by using AgNO3as dopant. Discussed the doping amount of Ag, the influence of roasting temperature onTiO2crystal phase structure by XRD, and means that TiO2accumulation preventedwhen Ag doped; SEM shows that size of prepared photocatalytic was500nm; XPSshows that there were three forms: AgO, Ag2O, Ag0on the surface of TiO2; Uv-vismeans that broaden the range of visible light response when Ag doped, and expandedthe photo corresponding to614nm; VSM shows that the modified composite catalysthas superparamagnetism; Discussing the influence of photocatalytic effect by dopingamount of Ag，calcined temperature, calcined time and so on. The result showed thatThe modified composite catalyst with0.2%doping amount had the best performancewhich were calcined2hours at450℃. Under the simulate sunlight irradiation with2hours, the degradation rate for phenol could achieve above79%. Ru-TiO2/SiO2/Fe3O4photocatalyst was prepared with sol-gel by usingRuCl3·3H2O as dopant, the influence of roasting temperature on TiO2crystal phasestructure by XRD, and means that anatase to rutile need high temperature when Agdoped; SEM shows that size of prepared photocatalytic was500nm; XPS shows thatthere were three forms: RuO2on the surface of TiO2and Ru4+displace Ti4+into thecrystal lattice of TiO2; Uv-vis means that broaden the range of visible light responsewhen Ru doped, and expanded the photo corresponding to750nm; VSM shows that themodified composite catalyst has superparamagnetism; Discussing the influence ofphotocatalytic effect by doping amount of Ru，calcined temperature, calcined time andso on. The result showed that The modified composite catalyst with0.4%dopingamount with Ru had the best performance which were calcined2hours at550℃.Under the simulate sunlight irradiation with2hours, the degradation rate for phenolcould achieve above75%.