介孔TiO_2的合成及光催化性能研究

Synthesis and Photocatalytic Performance of Mesoporous TiO_2

采用P123为模板剂,TiCl4和钛酸异丙酯为混合钛源,合成了介孔TiO2材料,并用焙烧和乙醇回流的方法进行脱模.用BET、TEM、XRD、TG-DTA等手段对TiO2材料进行了表征,考察了它们对水溶性偶氮染料甲基橙的光催化降解性能.结果表明,高温焙烧脱模的样品能形成介孔结构,且380℃焙烧6h的样品能晶化为锐钛矿相.而乙醇回流48h脱模的样品,模板剂脱除不彻底,且没有锐钛矿相和介孔结构形成.在对甲基橙的光催化降解中,起关键作用的不是催化剂的孔结构特征,而是其晶态.具有锐钛矿相的介孔TiO2有很高的光催化活性,可与市售的P25光催化剂相媲美.

The mesoporous TiO2 was synthesized by using TiCl4 and titanium isopropoxide as the Ti precursors and P123 as a template, followed by calcination or reflux with ethanol to remove template. The samples were characterized by BET, TEM, XRD and TG-DTA techniques. The photocatalytic degradation of methyl orange, a water-soluble azo-dye, catalyzed by these TiO2 samples was also investigated. The results indicate that mesostructure can be formed upon the calcination, and anatase crystal phase is obtained when the sample is calcined at 380℃ for 6 h. However the mesostructure and the anatase crystal phase cannot be formed on the refluxed sample, in which the template cannot be removed thoroughly. In the photo-degradation of methyl orange, the crystalline state rather than the mesostructure of TiO2 plays a vital role for the catalysis activity. Mesoporous TiO2 with anatase crystal phase possesses very high photocatalysis activity, which is comparable with P25 photocatalyst.