掺铁纳米TiO_2的制备及其光催化性能

Preparation and Photocatalytic Property of Iron-doped TiO_2 Nanoparticles

以TiCl4为原料,采用微波加热与常规加热2步合成法制备掺铁纳米TiO2. 用X射线粉末衍射(XRD)、透射电镜(TEM)、紫外可见吸收光谱(UV-Vis)、光电子能谱(XPS)等测试技术对其进行了表征. 结果表明,所制得的掺铁纳米TiO2是以锐钛矿为主相的混晶,平均粒径约为10 nm,适量Fe3+的掺杂能促进金红石相变,抑制锐钛矿晶粒的生长,使Ti2p电子结合能升高0.3 eV,并使TiO2吸光能力增强,带边吸收向可见光区移动. 在UVA段(320～400 nm)光照下,通过对维生素VB12的光催化降解,发现掺入摩尔分数为0.5%的Fe3+的纳米TiO2能明显提高其光催化活性,使维生素B12的降解速率提高2.3倍.

A series of iron-doped nano-titania were prepared from titanium tetrachloride precursor via a twostep method involving microwave and conventional heating treatments. The iron-doped nano-titania was characterized with XRD, TEM, UV-Vis and XPS techniques. The results indicated that the iron-doped nano-titania with an average diameter of 10 nm contained anatase as the main phase and ruffle phase. It was found that the ferric ion dopant of a proper concentration promoted the formation of the rutile phase, and reduced the crystallite size of anatase. An increase of 0. 3 eV in the binding energy of Ti2p was observed after the nano-titania was doped with 0. 5% （mole fraction） ferric ions. Moreover, the photoresponse shifted to the visible region for iron-doped nano-titania. Photocatalytic activity was evaluated by measuring the decomposition rates of vitamin B12 exposed to UVA（320 -400） radiation. The results indicated that the optimum mole fraction of ferric ions was 0.5% for the iron-doped nano-titania, which doubled the photocatalytic decomposition rate of vitamin B12 compared to that of undoped nano-titania.