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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。
Different amount of doped Li ~ + nano-TiO 2 was prepared by sol-gel method. The catalysts were characterized by X-ray diffraction and UV-vis spectrophotometer. The results show that Li ~ + doping promotes the transformation of TiO_2 anatase to rutile phase, inhibits the growth of TiO_2 crystal, and red shifts the absorption band of TiO_2 on rutile phase. Methyl orange solution was taken as the target degradation product, and the effects of Li ~ + amount, calcination temperature and catalyst dosage on the photocatalytic activity of TiO_2 were investigated. The experimental results showed that the mole fraction of Li ~ + doping was 4%, the calcination temperature was 500 ℃ and the amount of catalyst was 1.0g / L. The degradation rate of methyl orange solution reached 99.25% after irradiation with 300W UV lamp for 30min. The rate constant is 1.8 times that of pure TiO_2.