水热合成温度对纳米TiO_2特性及其可见光波段光催化性能的影响

Effect of hydrothermal temperature on the materials properties and its visible light photocatalytic efficiency of nanozised TiO_2 powder

以乙醇丙酮吡啶为溶剂,采用水热法制备了在可见光波段(≤450nm)具有良好光催化活性的纳米TiO2粉体.通过XRD、TEM、DTA、漫反射谱(DRS)与光电压谱等手段,研究了水热合成温度及250℃热处理对合成纳米TiO2粉体的材料特性,以及在可见光激发下纳米TiO2对甲基橙光催化降解的影响.结果显示,纳米TiO2晶型(锐钛矿)与粒径不随水热合成温度及热处理(250℃)条件的变化发生明显改变;各样品的表面吸附物状态以及可见光响应特性在未经热处理时随水热合成温度变化发生明显变化,而在经250℃热处理后则差异不明显;样品的表面吸附物状态、可见光响应以及可见光催化活性之间有显著关联.水热合成温度显著地影响了纳米TiO2粉体的表面吸附物状态及可见光催化活性.

Nanosized TiO2 powder with high photocatalytic efficiency in visible light wave band was prepared by hydrothermal method with acetone, ethanol, pyridine and TEOT as raw materials. XRD, TEM, DTA and DRS were used to characterize the effect of hydrothermal temperature and heat treatment procedure on properties of prepared nanosized TiO2 powder and its photocatalytic degradation efficiency for methyl orange under visible light irradiation （ ≥450 nm）. The results revealed that phase type and size of TiO2 powder were independent on the hydrothermal temperature and 250℃ heat treatment processing. On the other hand, the organics absorbed on the surface and optical absorption of visible light were obviously different among TiO2 powders prepared at various hydrothermal temperatures without heat treatment processing. However, that difference were disappeared after heat treatment at 250℃ for 2h. Moreover, it was clarified that the adsorbed organics, optical absorption and photocatalytic efficiency of visible light had close relation with each other. The nanosized TiO2, powder with hydrothermal temperature had significant effect on the surface adsorbed organics and the photocatalytic efficiency of visible light.