不同煅烧温度制备TiO_2及光解2-氯苯甲酸

为了考察煅烧温度对TiO2结构和光催化活性的影响,以酞酸丁酯作为前驱体,利用溶胶-凝胶法在不同煅烧温度下制备TiO2,并用亚甲基蓝测试其光催化活性。TG热重分析表明,450~700℃时TiO2有晶型变化,XRD表征说明,TiO2晶型受煅烧温度影响显著,其中450~600℃煅烧制备的TiO2为锐钛矿型,650℃煅烧时TiO2出现金红石晶型;亚甲基蓝光解实验结果表明,煅烧温度显著影响TiO2的光催化活性,其中,450~600℃煅烧TiO2对亚甲基蓝光解效果较好,光降解2.5h后降解率高达95%~97%;550℃煅烧制备的锐钛矿型TiO2对2-氯苯甲酸有一定光解催化效果,紫外光解4h后降解率高达80%左右,光解过程符合零级动力学模式。

PREPARATION OF TiO2 CALCINED AT VARIOUS TEMPERATURES AND PHOTOLYSIS OF 2-CHOROBENZOIC ACID

In order to investigate the influence of calcination temperature on the structure and photocatalytic activity of TiO2， nanometer titania photocatalysts have been prepared with sol-gel technique by using dibutyl phthalate as the precursor． Methylene blue was used to evaluate photocatalytic activity of TiO2 ． TG analysis results showed that the phase transition from anatase to rutile occurred during the temperature range of 450 ～ 700 ℃． XrD analysis results demonstrated that TiO2 crystal structure was affected by temperature obviously． TiO2 anatase crystal structure could be obtained in 450 ～ 600 ℃，and TiO2 rutile crystal structure occurred at 650 ℃． Photocatalytic degradation of methylene blue test described that calcination temperature had a great influence on TiO2 photocatalytic activity． Using TiO2 calcined at 450 ～ 600 ℃，the methylene blue photodegradation rate could reach 95% ～ 97% after 2. 5 h． The 2-chlorobenzoic acid photodegradation rate could reach 80% after 6 h using TiO2 calcined at 550 ℃，and the photodegradation process agreed to zero-roder reaction kinetics model．