纳米TiO2对气相中甲醛光催化降解的研究

采用溶胶-凝胶法制备了掺杂金属离子的纳米TiO₂光催化剂,运用透射电镜和X射线衍射手段对催化剂的结构进行了表征,并将制备的光催化剂负载于不锈钢丝网、玻璃弹簧和泡沫镍板3种不同载体上,以室内空气典型污染物甲醛气体为模型反应物,研究了3种不同改性纳米TiO₂光催化剂对甲醛气体的光催化作用,3种光催化反应器的催化效率以及环境因素对光催化效率的影响,同时考察了催化剂的失活特征.结果表明:该负载型纳米TiO₂光催化剂具有较高的光催化活性,其中掺镧1.5%(质量分数)的TiO₂对甲醛的降解率最高,60 min达到91.5%,大于掺铁和掺银;泡沫镍板作为负载载体的光催化效率大于玻璃弹簧和不锈钢丝网;循环风量和不同波长紫外光对该光催化反应影响不大,反应中催化剂存在失活现象,但在清洁后能够恢复. 

Photocatalytic Degradation of Formaldehyde in Air by Nanometer TiO2

A metal ion doped TiO_2 photocatalyst,which was prepared by the sol-gel method,was immobilized to stainless steel screen,glass spring and porous nickel mesh by coating.Transmission electron microscopy and X-ray diffraction were applied to characterize the structures of these photocatalysts.The photocatalytic degradation performance of three different modified nano-TiO_2 photocatalysts on formaldehyde in indoor air was investigated.The catalysis efficiency of the three photocatalytic reactors,the effects of environmental factors on catalysis efficiency,and the lifetime of the supported photocatalyst were studied.It was found that the gaseous photocatalysis over the supported photocatalyst is an efficient method for formaldehyde removal;the degraded rate of 1.5% La~3 -doped TiO_2 is excellent;and its conversion rate of formaldehyde was 91.5% in 60 min,more than that of Fe~3 -doped and Ag~ -doped TiO_2.The photocatalytic degradation rate of porous nickel mesh as carrier is more than that of glass spring and stainless steel screen.Changing circular wind speed and ultraviolet wavelength will not influence the photocatalytic degradation rate of formaldehyde.The deactivation of the supported photocatalyst has been observed but it is easily recovered by cleanness.