| Summary: | 碩士 === 國立中山大學 === 材料與光電科學學系研究所 === 101 === The sphere-like W,N-codoped TiO2 photocatalysts were prepared by a simple one-pot hydrothermal synthesis route, using tetrabutyl titanate as the TiO2 precursor through sol-gel process, urea and ammonium tungstate as the nitrogen and tungsten sources, and the triblock copolymer Pluronic P123 as the template. The morphology and microstructure characteristics of W,N-codoped titania photocatalysts with different amount of tungsten doping were characterized by means of XRD, BET, SEM, XPS, DRS and UV-Vis. The metal and nonmetal codoped W,N-TiO2 shows a much superior photocatalytic activity to the commercial titania P25 and undoped titania under visible light irradiation. A plausible mechanism of codoping is proposed. It is presumed that incorporation of nitrogen and tungsten leads to the formation of new mid-gap states and effectively narrow the band gap between the valence band and the conduction band; this greatly improves the photocatalytic activity in the visible light region. On the other hand, the tungsten ions with changing valences in the W,N-TiO2 are considered to act as trapping sites, which effectively decrease the recombination rate of photo-induced electrons and holes, thereby increasing the photo-oxidation efficiency of the catalysts.
|
|---|
