微波助离子液体中铈掺杂TiO_2光催化剂的制备及微波强化光催化活性

Microwave assisted preparation of cerium doped TiO_2 photocatalyst in ionic liquid and microwave enhanced photocatalytic activity

室温下,在离子液体[Bmim]PF6中,采用溶胶-凝胶法及微波辐射干法制备了铈掺杂纳米TiO2光催化剂TiO2-Ce,并测试了TiO2-Ce对甲基橙溶液的微波、紫外和微波-紫外条件下的降解率。着重考察了离子液体用量、微波干燥功率、微波干燥时间、焙烧温度、焙烧时间和铈掺杂量等因素对TiO2-Ce催化活性的影响。结果表明,离子液体用量5.6 mL,掺杂硝酸铈与钛酸丁酯物质的量比n(Ce)∶n(Ti)=0.075,功率210 W的微波条件下干燥20 min,高温箱式电阻炉550℃焙烧2.0 h,制得的TiO2-Ce催化剂具有较高的光催化活性。在微波、紫外和微波-紫外降解条件下,TiO2-Ce对甲基橙降解率分别为4.78%、93.82%和99.12%。表明在紫外光照条件下,微波辅射具有强化TiO2-Ce催化剂降解甲基橙的作用。同时用XRD、IR、BET和SEM对TiO2-Ce催化剂结构进行表征,结构分析表明,TiO2中掺入铈后制得的催化剂具有粒径均匀以及半孔宽(2.485 2 nm)、孔容(0.314 5 mL·g-1)、平均孔径(6.627 nm)和比表面积(94.934 m2·g-1)均较大等特点,这也是TiO2-Ce催化剂拥有较高的光催化活性的主要原因。

Using butyl titanate and cerium nitrate as the raw materials, cerium doped nano-TiOz photocat- alysts ZiO2-Ce were prepared in [ Bmim] PF6 ionic liquid at room temperature by sol-gel and microwave irradiation drying methods. The influence of ionic liquid dosage, microwave drying power and time, calcination temperature and time, and cerium doping on catalytic activity of TiO2-Ce photocatalysts for methyl orange degradation under microwave irradiation （MW）, ultraviolet lamp light （UV）, and microwave irradiation ultraviolet lamp light （MW-UV） was investigated. The results indicated that the optimized preparation condition was as follows ： [ Bmim ] PF6 dosage 5.6 mL, n （ Ce ） ： n （ Ti ） = 0. 075, microwave power 210 W, microwave drying time 20 min, calcination temperature 550℃, and calcination time 2 h. The as-prepared ZiO2-Ce photocatalyst possessed higher catalytic activity. The degradation rate of methylorange under MW,UV and MW-UV were 4.78% ,93.82% and 99.12%, respectively, which indicated that the microwave irradiation had the strengthening effect for degradation of methyl orange over TiO2-Ce photocatalyst. The structure of TiO2-Ce photocatalyst was characterized by IR, XRD, BET, and SEM. The results of structure analysis showed that TiO2-Ce photocatalyst exhibited higher photocatalytic activity due to its higher surface area （ 94. 934 m2 · g-1 ）, large average pore diameter （ 6. 627 nm ）, pore volume （0.314 5 mL · g-1） ,and wider average pore size（2. 485 2 nm）.