上转光剂掺杂新型纳米TiO2催化剂的制备及利用可见光降解反应艳蓝KN-R染料的研究

合成了一种新型含有稀土金属Er的上转光剂,40CdF2·60BaF2·0.8Er2O3,此上转光剂在488 nm可见光的激发下,产生了5个波长均小于387 nm的上转换紫外发射峰.采用超声波分散的方法制备出了上转光剂掺杂的纳米TiO2可见光光催化剂.采用X射线衍射(XRD)及透射电镜(TEM)对催化剂进行了表征.以反应艳蓝KN-R为研究对象,研究了在(三基色灯下发出的)可见光的照射下该可见光光催化剂的催化降解性能,并与未掺杂纳米TiO2粉末的催化剂性能进行了对比.实验结果表明,作为掺杂成分的上转光剂可有效地将可见光转化为紫外光并被纳米TiO2粉末吸收利用,在可见光照射50 h后反应艳蓝KN-R降解率达74.36%,大大高于未掺杂纳米TiO2的降解率(23.10%).

Preparation of novel nano TiO2 catalyst doped with upconversion luminescence agent and investigation on degradation of reactive deep blue KN-R dyestuff using visible light

A novel upconversion luminescence agent, 40CdF2?60BaF2?0.8Er2O3, was synthesized and the fluorescent spectrum was determined. This upconversion luminescence agent can emit five upconversion fluorescent peaks whose wavelengths are all below 387nm under the excitation of 488nm visible light. This upconversion luminescence agent was mixed in nanometer rutile TiO2 powder by ultrasonic dispersion and the new doped nanometer TiO2 photocatalyst utilizing visible light was prepared. The doped TiO2 powder was charactered by XRD and TEM and its photocatalytic activity was checked through the photocatalytic degradation of reactive deep blue KN-R as a model compound under the visible light irradiation emitted by three basic color lamp. Otherwise, in order to compare the photocatalytic activities the same experiment was carried out for undoped photocatalytic TiO2 powder. The degradation ratio of reactive deep blue KN-R in the presence of doped nanometer TiO2 powder reached 74.30 % under visible light irradiation at 50 h which was obviously higher than the corresponding 23.10 % in the presence of undoped nanometer TiO2 powder, which indicate that the upconversion luminescence agent prepared as dopant can effectively turn visible lights to ultraviolet lights which are absorbed by nanometer TiO2 particles and produce the electron-cavity pairs.