高活性Pt/TiO_2纳米管的制备及其光催化性能

Fabrication and Photocatalytic Performance of Pt/TiO_2 Nanotubes with High Activity

采用电化学阳极氧化法和浸渍-提拉法成功制备了高度有序的Pt改性TiO2纳米管(Pt/TNT)阵列电极,并运用场发射扫描电子显微镜(FESEM)、X射线衍射(XRD)、X射线光电子能谱分析(XPS)、紫外可见漫反射光谱(UV-Vis DRS)等手段对其进行表征,考察了其光电化学性质,并研究了该电极光电催化降解甲基橙染料废水的催化性能及其稳定性.结果表明,Pt的均匀负载成功地将TNT阵列电极的光响应范围拓宽到可见光区域,光电流密度达到负载前TNT阵列电极的18倍;Pt/TNT阵列电极对甲基橙的降解符合拟一级动力学,其反应速率常数为TNT阵列电极的3倍,这主要归结于Pt与TiO2间的肖特基势垒和纳米管阵列结构带来的较大比表面积、有效的光生电子和空穴的分离与传输和宽的光响应范围.

The Pt/TiO2 nanotube （Pt/TNT） arrays electrode was prepared using electrochemical anodiza- tion and dipping-pulling method. The properties of the composite electrode were characterized by field emission scanning electron microscopy （FESEM） , X-ray diffraction （ XRD ） , X-ray photoelectron spec- troscopy（XPS）, and UV-Vis diffuse reflectance spectroscopy （UV-Vis DRS）. The photoelectrochemieal properties, photoelectrocatalytic activity and stability of Pt/TNT arrays electrode for the degradation of methyl orange were investigated. The results indicate that the uniform dispersion of platinum successfully broadens the absorption spectrum of TNT arrays electrode to visible light region and the photocurrent den-sity of Pt/TNT arrays electrode is 18 times that of TNT arrays electrode. The degTadation of methyl orange on Pt/TNT arrays electrode conforms to pseudo first-order kinetics and the reaction rate constant is about 3 times that of TNT arrays electrode. The enhanced photocatalysis is ascribed to the higher surface volume ratio, the more effective separation and migration for the photogenerated electron-hole pairs, and an im- proved UV light response because of nanotubular structures and the Schottky barriers between Pt and TiO2.