尿素为氮源N-TiO2的制备、表征及光催化性能

以钛酸丁酯为前驱体,以尿素为氮源,采用溶胶-凝胶法制备了不同N含量的TiO2光催化剂(N-TiO2).通过X-射线衍射(XRD)、紫外-可见吸收光谱(UV-Vis)、分子荧光光谱(PL)、X-射线光电子能谱(XPS)等检测手段对其结构和物理性能进行了表征.结果表明,N的掺杂能抑制锐钛矿相TiO2向金红石相的转化,能将TiO2的吸收边波长拓宽到可见光区域,能加速光生电子-空穴对的分离,提高光催化活性.在以可见光为光源进行重铬酸钾的光催化还原和苯酚的光催化氧化反应中,9%N-TiO2-500表现出了最强的光催化活性,且在光催化活性的稳定性实验中,表现出良好的光催化活性的稳定性,能多次重复使用.

Preparation, Characterization Photo-catalytic Activities of N-TiO2 with Urea as Nitrogen Source

Nitrogen-doped TiO2 catalysts (N-TiO2) with different nitrogen content were prepared by a modified sol-gel method, using tetrabutyl titanate as the precursor and urea as the nitrogen source. Their structure and physical properties were characterized by means of X-ray diffraction (XRD), UV-Vis absorption spectroscopy, photoluminescence (PL), and X-ray photoelectron spectroscopy (XPS). The results show that the doping of Nitrogen can effectively suppress the phase transformation of TiO2 from anatase phase to rutile phase, can extent the absorption edge wavelength to visible light, can accelerate the separation of electron-hole pairs and improve the photo-catalytic activity. The photo-catalytic activities of N-TiO2 were evaluated using the photo-catalytic reduction of Cr(VI) and oxidation of phenol under visible light irradiation. It was found that the 9% N-TiO2-500 exhibits higher activities than those of Degussa P25 and TiO2 without Nitrogen, and has an excellent long-term stability and can be repeated used.