【作者】 全学军； 赵清华； 谭怀琴； 桑雪梅；

【Author】 QUAN Xue-jun, ZHAO Qing-hua, TAN Huai-qin, SANG Xue-mei (Department of Chemical and Biological Engineering, Chongqing Institute of Technology , Chongqing 400050,China)

【机构】 重庆工学院化学与生物工程学院；

【摘要】 首次用共沉淀法制备了掺镧二氧化钛光催化剂(La3+-TiO2),用罗丹明B为模型污染物对其光催化活性进行了评价,并用XRD、SEM和电子探针分析了用共沉淀法和溶胶-凝胶法制得的光催化剂之间的差异。实验结果表明:用共沉淀法制备的La3+-TiO2 具有较高的光催化活性,光催化剂的粒子和团聚体形态受掺杂过程的影响。与溶胶-凝胶法相比,共沉淀法能够提高镧对TiO2晶相由锐钛型向金红石型转化的抑制作用,有利于通过较高的热处理温度获得晶格完整的锐钛型La3+-TiO2光催化荆。镧的最佳掺杂量大约为1％,对于用共沉淀法和溶胶-凝胶法制得的掺镧 1％的光催化剂,其表面上[O]／[Ti]原子比约为2．49, 用共沉淀法制得的掺镧光催化剂具有较高活性的原因可能主要在于其较完整的锐钛型结构。光催化剂的粒子形态和表面上Ti3+的不同含量可能是导致光催化活性差异的因素。用共沉淀法制备La3+-TiO2的最佳条件为:掺镧量1%;煅烧温度800℃;煅烧时间2h。由于共沉淀法使用价格相对便宜的无机原料,不用有机溶剂,过程较简单,因而在工业生产上具有较大的应用前景。更多还原

【Abstract】 The lanthanum-doped TiO2 (La3+ -TiO2) photocatalysts were first time prepared by a coprecipitation method. Rhodamine B was used as a model chemical in this work to evaluate the photocatalytic activity of the catalyst samples. The catalyst samples were characterized by XRD, SEM and electronic probe microanalyzer to find the differences between the samples prepared by coprecipitation and sol-gel process. The experimental results showed that the La3+ TiO2 catalysts prepared by coprecipitation exhibited a higher photocatalytic activity as compared with that prepared by the usually used sol-gel process, the morphology of the primary particles and agglomerates of the La3+ -TiO2 catalyst powders was affected by doping process. As compared with the sol-gel process, the coprecipitation process can enhance the inhibition effect of lanthanum doping on TiO2 phase transformation from anatase to rutile during heat treatment, leading to a more perfect crystal structure of anatase La3+-TiO2 catalysts by using a higher temperature of heat treatment. The optimum amount of lanthanum doping is ca. 1. 0 wt% , and the surface atomic ratio of [O]/[Ti] is ca. 2. 49 for 1. Owt% La3+-TiO2 catalysts prepared by the coprecipitation and sol-gel processes. The enhancement of the photocatalytic activity of the catalysts prepared by coprecipitation is mainly attributed to its more regular anatase structure. The differences in the morphology of particles and the content of Ti3+ on the surface of the La3+-TiO2 catalysts could also be the factors leading to the different photocatalytic activities. The optimum preparation conditions are 1. 0 wt. % doping amount of lanthanum, calcination temperature 800℃ and calcination time 2h for the coprecipitation process. As compared with the sol-gel process, the coprecipitation process used relatively cheap inorganic raw materials and a simple process without organic solvents. Therefore, the coprecipitation method provides a potential alternative in realizing large scale production.更多还原