氮镧共掺杂的二氧化钛光催化剂制备及其工艺优化

Preparation and Process Optimization of TiO_2 Photocatalysts Co-doped with Nitrogen and Lanthanum

采用溶胶凝胶法,以三乙胺为氮源,制备氮和镧共掺杂的TiO_2光催化剂。通过X射线衍射(XRD)、扫描电镜(SEM)、紫外-可见漫反射光谱(UV-Vis DRS)对样品进行表征。以亚甲基蓝为目标降解物,在可见光下考察光催化剂的催化活性,结果表明0.8N/La/TiO_2具有较好的催化活性,采用正交法对0.8N/La/TiO_2催化亚甲基蓝进行工艺优化,影响亚甲基蓝降解的主次顺序为:时间>亚甲基蓝初始浓度>催化剂用量>反应温度,该反应的最佳工艺组合为时间(180 min)、催化剂用量(30 mg)、亚甲基蓝初始浓度(10 mg/L)、反应温度(30℃),在该条件下,亚甲基蓝的降解率达到79.3%,催化反应过程近似符合一级反应动力学方程。

N and La co-doped TiO2 nanocatalysts were successfully synthesized through a sol-gel method by using triethylamine as nitrogen source. The products were characterized by X-ray diffraction （XRD） , scanning electron microscopy（SEM） and UV-vis diffuse reflectance spectroscopy（ UV-Vis DRS ）. The photocatalytic activities of the N and La co-doped TiO2 nanoeatalysts were compared by removing methylene blue（MB） under visible light irradiation. The results show that the 0.8N/La/TiO2 has higher activity. Meanwhile, the orthogonal test was used to optimize the photocatalysis process. The order of the influence on degradation of methylene blue is reaction time, the initial concentration of MB, catalyst amount and reaction temperature. The optimum condition is reaction time （ 180 min）, catalyst amount （30 mg）, the initial concentration of MB （10 mg/L）, and reaction temperature （30 ℃）. The photodegradation process of MB can be considered as a pseudo first-order kinetics reaction