微波助离子液体中铜–铈共掺杂TiO₂光催化剂的制备及微波强化光催化活性

Preparation of Copper and Cerium Co-Doped TiO₂ Photo-Catalysts with Microwave Irradiation in Ionic Liquid and Microwave Enhanced Photo-Catalytic Activity

摘要: 在[Bmim]PF₆离子液体中，用微波辐射干燥的方法制备了铜–铈共掺杂纳米二氧化钛光催化剂TiO₂-Cu-Ce，用IR、XRD、SEM、BET对催化剂进行了表征。通过测试催化剂TiO₂-Cu-Ce对甲基橙溶液的微波(MV)、紫外(UV)、微波–紫外(MV-UV)三种条件下的降解率，着重考察了微波加热功率、微波加热时间、煅烧温度、煅烧时间及铜和铈掺杂量等因素对TiO₂-Cu-Ce催化活性的影响。结果表明，掺杂物质硝酸铜和硝酸铈与钛酸丁酯的物质的量之比分别为n(Cu)/n(Ti) = 0.025和n(Ce)/n(Ti) = 0.050，在微波功率为210 W时干燥20 min，再在高温箱式电阻炉中于500℃下煅烧2 h，所制得的TiO₂-Cu-Ce催化剂具有较高的光催化活性；在MW、UV和MW-UV三种降解条件下，TiO₂-Cu-Ce对甲基橙的降解率分别为6.89%、96.91%、99.85%；并且在三种降解条件下，甲基橙降解率始终是：MW-UV > UV > MW。这表明在紫外光照条件下，微波辐射具有强化TiO₂-Cu-Ce催化剂降解甲基橙的作用。催化剂结构分析表明，TiO₂中掺入铜和铈后制得的催化剂，具有粒径均匀，比表面积、孔容、平均孔径和半孔宽均较大等特点，这也是TiO₂-Cu-Ce催化剂具有较高的光催化活性的主要原因。

Abstract: Copper and cerium co-doped TiO₂ photo-catalyst TiO₂-Cu-Ce were obtained using titanium tetrabut-oxide as a precursor in [Bmim]PF₆ ionic liquids which were prepared by microwave irradiation at room temperature. The crystal structure of catalytic samples were measured and characterized by XRD, IR, SEM, BET with the related analysis software. Catalytic degradation reaction could be quantified in terms of methyl orange with microwave irradiation (MW), ultraviolet lamp light (UV), and microwave irradiation‑ultraviolet lamp light (MW-UV). The results indicated that the optimized conditions of copper and cerium co-doped TiO₂ were prepared at an n(Cu)/n(Ti) ratio 0.025, n(Ce)/n(Ti) ratio 0.050, dried in microwave with the power of 210 W for 20 min and calcined at 500˚C for 2 h. When the catalyst used to degrade methyl orange, the degradation rates of methyl orange under MW, UV and MW-UV were respectively 6.89%, 96.91%, 99.85%. Moreover, the degradation rate of methyl orange with MW-UV was all along the highest under the three degradation conditions, which indicated the microwave irradiation had the strengthening effect for degradation of methyl orange when TiO₂-Cu-Ce used as the photo-catalyst. Structure analysis of catalyst showed that the main reason for the higher photo-catalytic activity was that TiO₂-Cu-Ce had got higher surface area, almost similar particle size, larger total pore volume and wider average pore size.