TiO_2-HNbMoO_6复合材料的结构特征及其光催化性能

Structural Features and Photocatalytic Performance of TiO_2-HNbMoO_6 Composite

通过插层-柱撑的方法制备了新型的复合材料TiO_2-HNbMoO_6。采用粉末X射线衍射(XRD)、高分辨透射电子显微镜(HRTEM)、激光拉曼光谱(LRS)、X射线光电子能谱(XPS)、紫外-可见漫反射光谱(UV-Vis DRS)及H_2程序升温还原(H_2-TPR)等技术对样品的相结构和它的微结构、骨架特征及光谱响应特性以及分散相粒子与片层间的相互作用进行表征,利用N_2吸附-脱附法对样品的比表面积进行了表征,并通过模拟太阳光降解有机染料亚甲基蓝(MB)溶液考察复合材料的光催化活性。结果表明,HNbMoO_6与TiO_2复合后样品层间距增大,但无TiO_2晶相生成,主体材料中的Nb―O键和客体材料中的Ti―O键复合前后发生明显变化等,证明了TiO_2在HNbMoO_6层间高度分散,并呈现明显的相互作用。复合后样品比表面积是本体材料的4倍有余,禁带宽度变窄,它在吸附和模拟太阳光照射下催化降解MB中的优越的活性都是主客体间明显的协同效应的结果。

A novel composite material TiO_2-HNbMoO_6 was prepared by an intercalation-pillar route. The phase and its microstructure, skeleton feature, spectral-response characteristics, and the interaction between interlayer species and nanosheets were characterized using powder X-ray diffraction（XRD）, high resolution transmission electron microscopy（HRTEM）, laser Raman spectroscopy（LRS）, X-ray photoelectron spectroscopy（XPS）,UV-Vis diffuse reflectance spectroscopy（UV-Vis DRS）, and H_2 temperature-programmed reduction（H_2-TPR）.The specific surface areas of the samples were measured by N_2 adsorption-desorption isotherms. The synergistic effect between the host and the guest of the composites was evaluated by the degradation of methylene blue（MB） dye under simulated sunlight. The results, such as the increase of the d-spacing, the absence of TiO_2 crystalline phase, and the change of the Nb―O bond in the main body and the Ti―O bond in TiO_2 before and after composition, demonstrate that TiO_2 is uniformly dispersed in the interlayer of HNb MoO_6, indicating the interaction between the host laminates and the guest titanium oxide species. The specific surface area of the composite was four times that of its host material, the narrowing band gap, the better adsorption ability, and the superior photocatalytic activity of TiO_2-HNb MoO_6 were because of the synergistic effect between the host and the guest.