La、Co金属共掺杂TiO_(2)光催化材料的降解活性及动力学研究

Study on Photocatalytic Activity and Kinetics of TiO_(2) Co-doped with La and Co Metal

为提高二氧化钛光催化降解效率,采用水热法合成了稀土La及过渡金属Co共掺杂的TiO_(2)复合光催化剂,并通过扫描电镜(SEM)、X射线衍射(XRD)、紫外-可见漫反射光谱(UV-Vis DRS)等手段对材料进行了表征。以甲基橙和罗丹明B为模型污染物,研究La及Co共掺杂TiO_(2)光催化剂上催化降解活性,并对其催化降解动力学进行初步讨论。结果表明:水热法制得复合催化剂的形貌为球形结构,其中TiO_(2)为金红石相晶型,共掺杂后TiO_(2)的晶体结构未发生改变;La、Co共掺TiO_(2)复合材料的降解能力相比纯TiO_(2)有显著提高。当溶液浓度均取5 ppm时,1%(Co+La)/TiO_(2)催化剂上甲基橙溶液降解率为85.45%,1%(Co+La)/TiO_(2)催化剂上罗丹明B溶液降解率为94.56%。反应遵循Langmuir-Hinshelwood模型,具有一级反应动力学特征。

To improve the photocatalytic degradation efficiency of titanium dioxide,TiO_(2) composite photocatalysts co-doped with rare earth La and transition metal Co were prepared by hydrothermal method using tetra-n-butyl titanate as raw material,and characterized by XRD,SEM and UV-Vis DRS.Taking methyl orange and Rhodamine B as model pollutants,the activity of composite photocatalys and the effect of La and Co co-doping on TiO_(2)t were studied,and the catalytic degradation kinetics analysis was preliminarily discussed.The results showed that the La,Co co-doping on TiO_(2) catalyst is spherical structure,TiO_(2) is rutile phase crystal,La and Co doping did not change the crystal structure of TiO_(2).The result of photocatalytic degradation experiments showed that the degradation ability of(La,Co)co-doped TiO_(2) composites was significantly improved compared with pure TiO_(2),when the solution concentration was 5 ppm,the degradation rate of methyl orange solution on 1%(Co+La)/TiO_(2) catalyst was 85.45%,and the degradation rate of Rhodamine B solution on 1%(Co+La)/TiO_(2) catalyst was 94.56%.The degradation reaction accords with Langmuir-Hinshelwood model and has the first-order reaction kinetics characteristics.