负载型光催化材料CeO2-TiO2/SiO2的表面结构与光响应性能

采用表面改性法制备了负载型光催化材料CeO2-TiO2/SiO2,并用X射线衍射,比表面积测定,红外光谱,程序升温还原和紫外可见漫反射光谱技术对固体材料的结构和光响应性能进行了表征.结果表明,CeO2与TiO2在材料表面存在相互修饰作用,CeO2能拓展TiO2的光响应范围,使TiO2吸光区域由紫外拓宽至可见光区,从而提高材料的光能利用率;Ti4 可以进入CeO2晶格,形成Ce-O-Ti键合,使得Ti4 平均配位数增加,同时提高了CeO2体相晶格氧的活性;TiO2有助于提高CeO2在载体表面的分散程度,减小CeO2的微晶尺寸,提高固体材料的能隙值和氧化还原能力.

Surface Configuration and Optical Absorption of Supported Photocatalytic Material CeO2 -TiO2/SiO2

Supported CeO_ 2 -TiO_ 2 /SiO_ 2 was prepared by surface modification method and its structure and optical absorption behavior were characterized by BET, XRD, IR, TPR and UV-vis DRS techniques. The results showed that CeO_ 2 and TiO_ 2 can modify each other over CeO_ 2 -TiO_ 2 /SiO_ 2 surface. Coupling CeO_ 2 with TiO_ 2 extends the optical absorption from UV to visible region, which can increase the efficiency in utilizing the light. Ti~ 4 can be incorporated into the cubic CeO_ 2 and Ce-O-Ti bridges are formed, which increases the average coordination number of Ti~ 4 and improves the redox property of CeO_ 2 .TiO_ 2 promotes the dispersion of CeO_ 2 on silica support and diminishes the size of microcrystalline CeO_ 2 . The edge energy of CeO_ 2 -TiO_ 2 /SiO_ 2 is higher than that of bulk CeO_ 2 due to the quantum effect of nano-sized surface characteristics, which effectively enhance the redox ability of photo-generated hole-electron pairs.