TiO_2表面NiO光催化活性中心的构建及其光催化析氢性能研究

Fabrication of NiO Photocatalytic Active Center over TiO_2 and Photocatalytic Properties for H_2 Production

本文采用离子快速注入法,在低温条件下利用微量NiO物种对TiO_2光催化剂表面微结构进行了修饰和改性,构建了NiO光催化反应活性中心。研究结果表明,Ni物种是以TiO_2-NiO-H形式存在于TiO_2表面;相对于未修饰的TiO_2光催化剂,NiO的修饰很大程度上提高了其光催化析氢性能,在最佳条件下,放氢速率由1.1μmol·h^(-1)提高到241.4μmol·h^(-1)。另外,Ni物种含量,热处理温度,乙醇电子给体浓度,催化剂悬浮浓度对光催化析氢性能也有明显的影响。光电化学实验结果表明,NiO的表面修饰能够产生有效的光催化反应活性中心,增强了光生电子-空穴电子对的分离效果。所制备的光催化剂采用X射线粉末衍射(XRD),光电子能谱(XPS)等技术进行表征。

The surface microconstrure of TiO_2 photocatalyts was modified and optimized with NiO-H species at low-temperature using ion quick-impregnation method.The catalysts were characterized with X-ray diffraction（XRD）, and X-ray photoelectron spectrometer（XPS）.The results show that a small amount of Ni^（2＋） ion was deposited on the surface of TiO_2 in TiO_2-NiO-H form,an appropriate amount of NiO modified on TiO_2 photocatalyst exhibited a great improvement in hydrogen production as compared with the bare TiO_2,and under the optimal condition,the hydrogen production rates have increased from 1.1μmol·h^（-1） to 241.4μmol·h^（-1）.The Ni content,heat-treatment,ethanol content,pH value,and catalyst content have obvious effects on the hydrogen production rate.The results of the photoelectrochemical studies show that the appropriate amount of NiO modified on TiO_2 photocatalyst could produce photocatalytic reaction sites -TiO_2-NiO-H for the photoinduced hole,and enhance the separation of the photo-induced electron-hole pairs.