氮掺杂二氧化钛粉体的制备及掺杂机理研究

Preparation and Mechanism of N-Doped TiO_2 Powders

以钛酸四丁酯为钛源,尿素为氮源制备了N掺杂二氧化钛粉体。采用X射线衍射、透射电镜和紫外-可见吸收光谱对粉体晶粒尺寸、物相及光吸收性质进行了表征。结果表明,N掺杂有效抑制了二氧化钛晶粒的长大,并使TiO2光吸收效果大大提高。采用密度泛函方法对掺杂机理进行研究证明,N掺杂有效减小了TiO2带隙宽度,使吸收谱红移,相比替位氮掺杂,间隙氮掺杂更有利于提高光吸收效率。

N-doped TiO2 powers have been prepared using tetrabutyl titanate and urea. The properties of phase/ size/absorbanee were characterized by means of X-ray diffraction （XRD）, transmission electron microscopy （TEM）, UV-Vis absorption spectroscopy. The results indicate that particle size of N-doped TiO2 decreased and the absorption effect increased greatly. In order to prove the experimental results, we studied the doping mechanism using DFT. The band gap has been decreased effectively because of doping. Compared with substitutional N- doped TiO2, interstitial N-doped TiO2 is more beneficial to the light absorption.