超声波制备介孔结构的氮掺杂TiO2纳米晶及其可见光催化性能

采用超声波辐射法制备了具有介孔结构的高浓度氮掺杂TiO₂纳米晶(N/TiO₂).采用N₂物理吸附、X射线粉末衍射、X射线光电子能谱、透射电镜、光致发光谱和紫外-可见漫反射光谱等手段对N/TiO₂进行了表征.以波长为400~660nm的可见光为光源,以水体污染物邻苯二甲酸二甲酯为降解对象,考察了不同制备方法对N/TiO₂光催化性能的影响.结果表明,超声波辐射使氮掺杂浓度提高了2.2倍,该法制备的N/TiO₂同时具有较好的介孔结构,表现了更高的光催化降解邻苯二甲酸二甲酯的活性.其活性提高的主要原因是N/TiO₂含有更高浓度的氮和对可见光具有更强的吸收能力.

Ultrasonic fabrication of N-doped TiO2 nanocrystals with mesoporous structure and enhanced visible light photocatalytic activity

An ultrasonic method was developed to fabricate novel mesoporous TiO₂ nanocrystals doped with a high concentration of N (N/TiO₂). The nanocrystals were characterized by physicochemical methods including N₂ physical adsorption/desorption, X-ray diffraction, X-ray photoelectron spectroscopy, photoluminescence spectroscopy, transmission electron microscopy, and UV-Vis diffuse reflectance spectroscopy. The photocatalytic degradation of dimethyl phthalate, a hazardous chemical in water, by the prepared N/TiO₂ nanocrystals under visible light irradiation (400?660 nm) was investigated. The results show that N-doping efficiency under ultrasonic irradiation is 3.2 times higher than under typical conditions, and the produced TiO₂ nanocrystals have mesoporous structure. N/TiO₂ fabricated under ultrasound exhibited much higher efficiency for the degradation of dimethyl phthalate than that prepared under typical conditions. The high photocatalytic degradation activity of N/TiO₂ fabricated under ultrasound is mainly attributed to its high N content effectively increasing its ability to absorb visible light.