不同晶型TiO_2的制备与光催化性能研究

Preparation and Photocatalytic Activity of TiO_2 with Different Crystal Structures

采用溶胶凝胶法,利用不同温度热处理制备了不同晶体结构的TiO_2纳米晶。利用XRD、SEM、EDS、XPS等分析方法对样品的晶体结构、形貌、化学元素组成以及价态进行了表征。结果表明400℃、500℃热处理TiO_2为锐钛矿晶型,600℃热处理为锐钛矿金红石混合晶型,700℃热处理为金红石晶型,单颗粒子呈现类似球形形貌。以罗丹明B为目标污染物,测试了样品的光催化性能,结果表明400℃热处理TiO_2具有最高的光催化活性,3 h后对罗丹明B的降解率达到94.6%,其反应速率常数达到0.969 h^(-1)。

The nanocrystalline TiO2 with different crystal structures were prepared by sol-gel method at different temperatures. The crystal structure, morphology, element composition and chemical state of the samples were analyzed by XRD, SEM, EDS and XPS, respectively. The results show that TiO2 form anatase crystal structure at the temperature of 400℃ and 500℃, form anatase / rutile mixed crystal structure at the temperature of 600℃, and form futile crystal structure at the temperature of 700℃. The single particle presents approximate spherical morphology. The rhodamine B was employed as the target pollutant to evaluate the photocatalytic activity of the samples. The results reveal that TiO2 which is annealed at 400℃ shows the highest photocatalytic activity and reaction rate constant. The degradation rate and the reaction rate constant are 94.6% and 0. 969 h^-1 after illumination for 3 h.