Study On Low-temperature Synthesis And Photocatalytic Performance Of Ti-based Catalyst

]Abstract: Due to the advantages of high photocatalytic activity, toxic-free and low cost, titania has been extensively used in the fields of environmental protection, solar energy conversion, sunscreen cosmetics, textile, paint, rubber etc. So many problems, however, existed in the preparation process of titania and its practical application, such as complex preparation process, the low efficiency for utilizing solar light and so on. On the basis of previous research, aiming at getting over the above problems and simplifying the preparation procedure,this dissertation did original exploration on the preparation and modification of titania photocatalyst. The contents are as follows:TiO₂·nH₂O was synthesized by hydrolyzing tetrabutyl titanate(Ti(OBu)₄) with water, which was released from an esterification reaction between the acetic acid and ethanol, then it was crystallized at low temperature to yield nano-TiO₂. Cu-doped titanium dioxide photocatalyst was prepared by the homogeneous hydrolysis and low temperature crystallization method, using tetrabutyl titanate as titanium source and the Cupric acetate as the doping agent; Nitrogen-doped titania was produced by homogeneous hydrolysis and low temperature crystallization method, using thiourea as nitrogen source and tetrabutyl titanate as titanium source; TiO₂ was prepared by microwave heating hydrolysis, the Ti(SO₄)₂ was used as a raw material. The photocatalysts were characterized by UV–Vis diffuse reflection spectrum, X-ray powder diffraction(XRD), Scanning electron microscopy(SEM), Brunauer–Emmett–Teller(BET), TG-DTA and Fourier transform infrared spectrophotometer (FT-IR). Photocatalytic activity of the catalysts was evaluated by the methyl orange(MO) photodegradation in aqueous solution under visible light or ultraviolet(UV) irradiation at room temperature. The results indicated that TiO₂ powders showed high activity under UV irradiation, which can be prepared by homogeneous hydrolysis and low temperature crystallization method. In order to obtain high photocatalytic performance of TiO₂ photocatalyst, the optimum mole ratio of Ti(OBu)₄:ethanol: acetic acid was 1:7:14; The photocatalytic activity of Cu-doped titania were higher than that of P-25 TiO₂ under visible light or the UV irradiation; Compared with P-25 TiO₂, the photocatalytic activity of Nitrogen-doped titania was enhanced remarkably in the visible light region, but the photocatalytic activity of N-doped titania was declined under the UV irradiation Compared with P-25 TiO₂; TiO₂ powders was prepared by microwave heating hydrolysis method showed fine activity. Meanwhile, the effects of prepared conditions on the photocatalytic activity of photocatalysts were investigated.