稀土元素Ce掺杂TiO_2光催化剂制备及微波强化光催化活性

在Bmim]PF6离子液体介质中微波辅助制备稀土元素Ce掺杂改性的TiO_2光催化剂TiO_2-Ce,以甲基橙溶液和苯酚溶液为模拟污染物,在紫外光照和微波辐射-紫外光照降解条件下考察TiO_2-Ce催化剂的光催化活性。利用荧光技术以对苯二甲酸作为荧光探针检测TiO_2-Ce催化剂表面产生的羟基自由基,并对光催化降解反应进行动力学分析,以了解光催化降解反应机理。结果表明,通过优化反应条件制得的TiO_2-Ce催化剂具有较高光催化降解活性和热稳定性,在紫外光照和微波辐射-紫外光照条件下降解60 min后,甲基橙降解率分别为98.6%和99.3%,苯酚降解率分别为96.6%和97.2%。荧光光谱分析表明,TiO_2-Ce在微波辐射-紫外光照条件下产生的羟基自由基比紫外光照多,因而微波辐射-紫外光照具有强化TiO_2-Ce降解模拟污染物作用的效果。反应动力学数据表明,TiO_2-Ce光催化降解甲基橙溶液反应呈一级反应动力学规律,其表观速率常数k最大值为0.056 2 min-1。

Preparation of Ce-doped TiO2 photocatalyst andits microwave enhanced photocatalytic activity

Using room temperature ionic liquid ［Bmim］PF₆ as the reaction medium,cerium doped TiO₂ photocatalyst TiO₂-Ce was prepared by microwave drying method and sol-gel method.The activity of TiO₂-Ce photocatalyst for photocatalytic degradation of methyl orange and phenol solutions as simulated pollutants was respectively investigated under ultraviolet irradiation(UV) and microwave irradiation with ultraviolet irradiation (MW-UV).With terephthalic acid as the fluorescence probe,the influence of ·OH on the surface of TiO₂-Ce on its photocatalytic activity was investigated by the fluorescence technology.In order to understand the reaction mechanism,the photocatalytic degradation kinetics was experimentally determined.The results showed that TiO₂-Ce catalysts prepared under the optimum condition had higher photocatalytic activity and heat stability.The degradation rates of methyl orange and phenol solution reached 98.6%,99.3%, 96.6%,and 97.2%,respectively,under the condition of UV and MW-UV irradiation for 60 min.The results of fluorescence spectra characterization indicated that the UV irradiation combining with MW technology could effectively improve the catalytic efficiency of TiO₂-Ce catalyst due to more amount of hydroxyl radicals produced under MW-UV irradiation than that under UV irradiation.The reaction kinetics data showed that the photocatalytic degradation of methyl orange on TiO₂-Ce catalyst fitted the first order kinetics model,and the maximum of apparent rate constant k was 0.056 2 min^-1.