微波载银对纳米二氧化钛相变及光催化性能的增效作用

Synergistic Effects of Microwave Doped Ag on the Phase Transformation and Photocatalytic Activity of Nano-Titania

用微波法制备含Ag量不同的系列载Ag纳米TiO2,发现微波载Ag对纳米TiO2的相变和光催化活性具有增效作用.采用X射线粉末衍射(XRD),X射线光电子能谱仪(XPS),Raman光谱及漫反射光谱(DRS)等方法表征微波载Ag纳米TiO2的性质.结果表明,载Ag纳米TiO2是锐钛矿和金红石相的混晶,随载Ag量的提高,促进纳米TiO2中锐钛矿相转化金红石相相变.以Ag0/Ag+两种价态载Ag,抑制纳米TiO2光生电子与光生空穴复合,使光响应范围红移,显著提高了光催化活性.在近紫外-可见光照射下,载Ag量(x)为0.05%的纳米TiO2对罗丹明B的光催化降解效果最好.

The Ag-doped nano-titania with different Ag contents were prepared by the microwave treatment. It was found that the microwave-treated Ag doping played synergistic effect on the phase transformation and the photocatalytic activity of nano-titania. On the basis of the characterization by X-ray diffraction, X-ray photoelectron spectrophotometry, Raman and diffuse reflectance spectroscopy, the prepared nano-titania were found to contain the anatase and futile phases, and the formation of the rutile phase was promoted with the increasing Ag content. The doped Ag species mainly exist as Ag^0/Ag＋, which can effectively inhibit the recombination of the photoinduced electrons and holes, and the photoresponse of the nano-titania was red-shifted. The drastic enhancement of the photocatalytic activity of the Ag-doped nano-titania was evaluated by measuring the decomposition rates of rhodamine B exposed to the near ultra- violet-visible light radiation. For the Ag-doped nano-titania, the highest degradation ratio was observed with the Ag content （x） of 0.05%.