掺杂Li^+纳米TiO_2光催化性能的研究

Study on photocatalytic activity of Li^+-doped TiO_2

采用溶胶-凝胶法制备不同掺Li^+量的纳米TiO_2,并通过X射线衍射、紫外可见分光光度计等手段对催化剂进行表征。结果表明,Li^+掺杂促进TiO_2锐钛矿向金红石相的转变,抑制TiO_2晶粒的生长,使金红石相TiO_2吸收带边发生红移。以甲基橙溶液为目标降解物,考察掺Li^+量、焙烧温度、催化剂用量等因素对TiO_2光催化活性的影响。实验表明,Li^+掺杂的摩尔分数为4%,煅烧温度为500℃,催化剂用量为1.0g/L,经300W紫外灯照射30min,甲基橙溶液降解率可达99.25%,动力学降解速率常数为纯TiO_2的1.8倍。

Li^＋ doped nanometer TiO2 with different molar ratio was prepared by sol-gel method,and the product was characterized by X-ray diffraction and UV-Vis spectrophotometry.The results showed that Li^＋ doping promoted the phase transformation from anatase to rutile after calcination,the growth of TiO2 nanocrystal was restrained,and Li^＋ doping resulted in the red shift of rutile TiO2 absorption edge.The photocatalytic activity of doped TiO2 was evaluated by degrading methyl orange,and investigated the amount of Li doping,roasting temperature,the amount of catalyst and so on.The results showed that the degradation rate of methyl orange was about 99.25% for 30 min under 300 W UV lamp,with 4% Li^＋ content（mole fraction）and the roasting temperature was 500℃,and the kinetic degradation rate constant was 1.8 times of pure TiO2.