Study On The Preparation And Photocatalysis Of Anatase TiO₂-based Composite

Abstract:TiO2is the most widely used one among varying photocatalysts, with the advantages of high stability, non-toxicity and corrision resistant. Besides, anatase TiO2shows a better photocatalytic performance than other types. For purpose of improving the separation efficiency of photo-induced carrier and extending light absorption of TiO2to the visible region, the preparation and process conditions of single-or codoped-anatase TiO2based composite were studied. The structure, morphology and optical absorption property of anatase TiO2composites were characterized in detail.The main contents and results of research were composed of three parts as follows:(1) The well-dispersive TiO2-ZnO-Zn2TiO4microspheres with a diameter about0.5-1μm were prepared by hydrothermal and template-free method, using Ti(SO4)2, Zn(NO3)2-6H2O as precusor and HMTA as hydroxyl relievers. The decolorization rate and apparent reaction rate under UV light within25min of TiO2-ZnO-Zn2TiO4microspheres prepared at180℃for9h were88.4%and8.131×10-2min-1, respectively. The band gap is shift from3.24eV(TiO2) to3.14eV(TiO2-ZnO-Zn2TiO4).(2) The ZnO/TiO2hollow microspheres were synthesized by one-step template-free method and urea and ammonium fluoride as additives. The diameter of the hollow microspheres is about0.5-2jim. After coupling, the band gap transferred from3.16eV(TiO2) to2.80eV(ZnO/TiO2). The ZnO/TiO2hollow microsphers(180℃,6h) shows a specific surface area of55.985m2·g-1, mean pore diameter of8.5nm and pore diameter in the range between2-13nm. The apparent reaction rate under UV and visible light were10.19×10-2min-1and7.46×10-3min-1, respectively.(3) HF released from NH4F and Ti(SO4)2as protonation conditions and NH3released from NH4F and urea as hydroxyl relievers are both cscnlial in preparing g-C3N4/Ti02. The band gap of TiO2, g-C3N4and g-C3N4/TiO2are3.19eV,2.67eV and2.70eV, respectively. The composite prepared at150℃shows a relatively high photo-activity, and the decolorization rate, apparent reaction rate and photo-current under visible light were94.1%,15.42×10-3min-1and50μA/cm-2, respectively.