负载型复合半导体V_2O_5-TiO_2/SiO_2表面V_2_O5和TiO_2的相互修饰作用  

Mutual Modification of V_2O_5 and TiO_2 on the Surface of Supported Coupled-Semiconductor V_2O_5-TiO_2/SiO_2

作　　者：胡蓉蓉[1] 钟顺和[1] 

机构地区：[1]天津大学化工学院,天津300072

出　　处：《催化学报》2005年第1期32-36,共5页

基　　金：国家重大基础研究前期研究专项资助项目 (2 0 0 1CCA0 3 60 0 )

摘　　要：采用表面改性法制备了负载型复合半导体材料V2 O5 TiO2 /SiO2 ,并用X射线衍射、比表面积测定、拉曼光谱、程序升温还原和紫外 可见漫反射光谱等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 ,V2 O5和TiO2 在负载型复合半导体V2 O5 TiO2 /SiO2 表面有相互修饰的作用 .一方面 ,V2 O5能扩展TiO2 的光响应范围 ,使TiO2 的吸光区域由紫外光区拓宽至可见光区 ,从而提高了复合半导体对光能的利用率 ;另一方面 ,TiO2 则有助于提高V2 O5在载体表面的分散程度 ,抑制VOx的聚合 ,减小V2 O5的微晶尺寸 ,提高固体材料的能隙值和氧化还原能力 .For photocatalyzing light alkanes to oxygen-containing chemicals, a supported coupled-semiconductor of V 2O 5-TiO 2/SiO 2 has been prepared by chemical modification method. XRD, BET, LRS, TPR and UV-Vis DRS techniques have been used to characterize the surface structure and light absorbing ability of the material. It is shown that V 2O 5 and TiO 2 on the surface of silica can modify each other. On the one hand, V 2O 5 expands the light-responding scope of TiO 2. For bulk TiO 2, only the UV light of 200～400 nm can excite it to produce photoexcited electron-hole pairs, while after coupling with V 2O 5, it may get some extra photoexcited electrons. The light of 400～650 nm excites the valence band of V 2O 5 to produce electrons, which transit from the V 2O 5 valence band to its conductor band, and then move to the TiO 2 conductor band. On the other hand, TiO 2 promotes the dispersion of V 2O 5 on the surface of silica. In general, V 2O 5 is easy to aggregate on the silica surface. The addition of TiO 2 strengthens the interaction of V 2O 5 and TiO 2, which effectively prevents VO x from aggregation, diminishes the size of crystalline V 2O 5 and makes it disperse well on the surface of silica. What is more, the edge energy of V 2O 5-TiO 2/SiO 2 is higher than that of bulk TiO 2 and V 2O 5, which can further weaken the movement and annihilation of the photoexcited electron-hole pairs and enhance its redox ability.

关 键 词：表面改性法 复合半导体 五氧化二钒 二氧化钛 负载型催化剂 光催化 吸光性 分散度 能隙值 

分 类 号：TN304[电子电信—物理电子学]