In离子掺杂二氧化钛纳米管可见光催化活性的研究

Photocatalytic Activity of Indium Doped TiO_2 Nanotube Under Visible Light

采用两步预掺杂方法制备出In离子掺杂二氧化钛纳米管可见光催化剂.可见光催化降解对氯苯酚实验证明:掺杂In离子量为3%的TiO2纳米管可见光活性最高,是纯TiO2纳米管的2倍以上.X射线衍射(XRD),X光电子能谱(XPS)和表面光电压谱(SPS)结果表明:当In离子掺杂浓度较小时,In离子取代晶格Ti的位置形成InxTi1-xO2取代式掺杂结构.In离子的掺杂能级与Ti离子的3d轨道形成混合价带,使禁带宽度变窄,增强了可见光响应.随着In离子掺杂浓度的增加,同时在InxTi1-xO2纳米管表面生成In2O3,形成InxTi1-xO2/In2O3纳米管复合结构.该复合结构有效地增加可见光响应,促进了光生载流子的分离,提高了光生载流子在固/液界面参加光催化反应的利用率,使纳米管催化剂可见光催化活性显著提高.

Indium doped TiO2 nanotubes were fabricated by a two-step pre-doping method. It was found that the TiO2 nanotubes with indium doped content at 3% exhibited the best photocatalytic activity being over twice as much as that of pure TiO2 nanotubes on the photocatalytic degradation of 4-chlorophenol under visible light. Based on XRD, XPS and SPS, it can be inferred that when the doped content is low, the indium ion substitutes Ti into the TiO2 lattice forming the InxTi1-xO2 structure and the In doped energy-band narrows the band gap by mixing with Ti 3d states. With increasing the doped content, In203 comes up on the surface of InxTi1-xO2 nanotubes to form the InxTi1-xO2/InwO3 composite structure. This composite structure efficiently enhances the visible light response, promotes photogenerated carriers separation and increases the utilization of photogenerated carriers in photocatalytic reactions at the solid/liquid interface, resulting in the higher photocatalytic activity under visible light.