Fe、N共掺杂改性TiO_2/AC复合光催化剂的制备及气相污染物降解性能

Preparation of Iron,Nitrogen co-doped TiO_2/AC Composite Photocatalysts and their Photocatalytic Activities for Degradation of Gaseous Pollutants

采用Sol-gel法制备了Fe、N离子共掺杂改性TiO_2/AC复合光催化剂,利用SEM、XRD、UV-Vis分光光度计对其结构及性能进行了表征。通过对气相甲苯、丙酮和甲醛的光催化降解实验,系统评价了离子掺杂量、抑制剂种类、TiO_2负载量、污染物起始浓度、污染物种类和催化剂循环使用次数对其性能的影响。结果表明,TiO_2以颗粒状镶嵌在AC孔隙内,且主要以锐钛矿相存在,Fe、N离子共掺杂实现了催化剂的可见光响应;确定最佳催化剂制备工艺为Fe、N离子共掺杂量8%、HAc为抑制剂、TiO_2负载量20%。催化剂对甲苯的降解率随起始浓度的增加而增加;催化剂对甲苯和丙酮的降解率较高(约为90%),对甲醛的降解率较低(约为35%);循环使用6次后,对甲苯的降解率仍高于P-25(商业纳米TiO_2)。

Titanium dioxide（TiO2）/activated carbon（AC） composite photocatalysts were synthesized based on iron（Fe） and nitrogen（N） co-doped by sol-gel method. Morphology and properties of them were studied by SEM, XRD and UV-Vis. The influences of ion co-doping content, inhibitor species, TiO2 loading ampunt, initial concentrations of pollutant, pollutant species, and the reuse time of photocatalysts on photodegradation rate of toluene, acetone and formaldehyde were evaluated. The results indicate that the photocatalysts are coated on the surface of AC and consisted of homogeneous anatase crystalline phase; there is an obvious enhancement in the adsorption of visible light. The optimum content of ion doping for both N and Fe atom is 8% when acetic acid is used as an inhibitor, and the op- timum loading amount of TiO2 is found to be 20%. Photocatalytic activity of TiO2/AC composites for toluene degradation increases with the increasing of the initial toluene concentration. In the process of different kinds of VOC degradation, the prepared photocatalysts exhibit higher ptotocatalytic activities for toluene and acetone（about 90%）, but lower for formaldehyde（about 35 %）. Toluene photodegradation rate is still slightly higher than that of P-25 （commercial nano-TiO2 ） when the photocatalysts is used repeatedly for six times.