N掺杂纳米TiO2可见光催化氧化丙烯的动力学行为

Kinetic Behavior of Visible Light Photocatalytic Oxidation of Propylene for N-Doped Nano-TiO_2

通过在不同温度的氨气气氛中处理纳米管钛酸(NTA)制得具有可见光响应的氮掺杂纳米二氧化钛.X射线衍射(XRD)谱表征结果显示,当温度高于400℃时,样品由正交晶系向锐钛矿相转变,700℃处理得到的样品除了锐钛矿相TiO2外还有TiN新相存在;紫外-可见扩散漫反射(DRS)结果表明,氮掺杂纳米TiO2在整个可见光区都有明显的吸收.不同波长可见光及不同气体流速的光催化氧化丙烯动力学研究表明,活性最好的N掺杂纳米TiO2催化剂(600℃NH3处理)对可见光的利用范围可扩展至500nm,低浓度丙烯光催化氧化反应为一级反应.

N-doped TiO2 （anatase） with high visible light photocatalytic activity was prepared by treating nanotube titanic acid （NTA） in NH3 flow at different temperatures. The crystalline structure of N-doped TiO2 determined by XRD was anatase when the treating temperature was higher than 400℃, however, a new phase （TIN） emerged at 700℃. The UV-Vis diffuse reflectance spectra （DRS） display that N-doped TiO2 has a continuous absorption at A λ≥ 400 nm. The photocatalytic activity of the N-doped TiO2 was determined by the photocatalytic oxidation of propylene under visible light irradiation. The highest photocatalytic activity was obtained for the catalyst treated at 600℃ in NH3 flow, which was active even under λ=500 nm, its kinetic behavior was accordant with the first order reaction formula.