水热法合成的介孔二氧化钛的结构表征及其对水中2,4,6-三溴苯酚的光催化降解活性

摘要

以聚丙二醇(PPG)为模板剂,采用水热法制备了可控介孔TiO2纳米晶体.醋酸水溶液为水解抑制剂和催化剂.运用X射线衍射、热重分析、扫描电镜和氮气吸附-脱附等技术对样品进行了表征.详细考察了制备过程、模板剂含量和煅烧温度等参数对样品结构和光催化活性的影响,并将样品用于紫外光下降解水体中典型溴代阻燃剂2,4,6-三溴苯酚的反应中,阐明制备的介孔TiO2结构与光催化活性之间的关系.结果表明,所制样品为具有规则孔道结构、较大的孔径和较高比表面积的介孔TiO2.其中,在400℃煅烧、PPG添加量为20％时所得介孔TiO2的光催化活性最高,反应1h可将100 μmol/L的2,4,6-三溴苯酚完全降解.%Well defined mesoporous TiO2 (M-TiO2) nanocrystallites were prepared by the hydrothermal method using polypropylene glycol (PPG) as template.The method differs from traditional methods in the use of an acetic acid aqueous solution instead of the conventional hydrolysis inhibitors and acid catalysts.The morphology and microstructures of M-TiO2 were characterized by X-ray diffraction,thermogravimetric and differential thermogravimetric,scanning electron microscopy,and nitrogen adsorption-desorption.The effects of the synthesis process,template reagent content,and calcination temperature on the microstrueture and photocatalytic activity were investigated.The relationship between the microstructure of M-TiO2 and its photocatalytic activity was studied by the photocatalytic degradation of 2,4,6-tribromophenol in water under UV irradiation.M-TiO2 with a regular channel structure,large pore size,and high specific surface area was successfully synthesized.The M-TiO2 synthesized by the hydrothermal method and calcined at 400 ℃ that used a PPG content of 20% gave the highest photocatalytic activity,and completely degraded 100 μmol/L 2,4,6-tribromophenol within 1 h.