不同价态碘对溶胶-凝胶法制备的I-TiO_2光催化剂结构和性能的影响

Effect of different valence iodine on structure and activity of I-TiO_2 photocatalysts synthesized by sol-gel method

分别以KI和KIO3为碘源,用改进的溶胶-凝胶法合成不同价态碘修饰的TiO2纳米材料。采用XRD、UV-Vis、SEM、EDS、TG-DTA和BET等手段对催化剂进行表征,比较不同价态碘修饰和煅烧温度对光催化剂结构和性能的影响。结果表明:KI和KIO3修饰的TiO2均为锐钛矿相,平均粒径约为10 nm。由于在催化剂表面形成I2,KI和KIO3修饰增强TiO2在可见光区的吸收能力。煅烧温度对KI修饰的催化剂影响较大,KI修饰可提高催化剂的比表面积和孔容,KIO3修饰改变TiO2的孔结构,增大孔径。在相同条件下,KI修饰的催化剂的比表面积是原催化剂的3.5倍(50.37 m2/g变为176.74 m2/g)。KI和KIO3修饰的TiO2在模拟太阳光和紫外光下对亚甲蓝的光活性均高于纯TiO2的。

The different valence iodine modified TiO2 nanomaterials were prepared by the improved sol-gel method using KI or KIO3 as the iodine sources.The modified TiO2 photocatalysts were characterized by XRD,UV-Vis,SEM,EDS,TG-DTA and BET.The effects of different valence iodine and calcinated temperature on the structure and properties of catalysts were investigated.The results show that the photocatalysts modified by KI or KIO3 contain 100% anatase crystalline phase of TiO2,and the average particle size of that are about 10 nm.Because I2 is formed on the catalyst surface,KI and KIO3 modification increase the absorption of TiO2 in the visible region.The calcination temperature has great effect on the modified KI catalyst.KI modification can increase the catalyst surface area and pore volume,and KIO3 modification changes the structure of TiO2 and increases the pore diameter of TiO2.Under the same conditions,the surface area of catalyst modified by KI（176.74 m2/g） is 3.5 times than that of pure TiO2（50.37 m2/g）.The photoactivity of TiO2 modified by KI and KIO3 on the methylene blue is greater than that of pure TiO2 under simulated solar light and UV light.