Fabrication of a TiO2/Au Nanorod Array for Enhanced Photocatalysis

A highly ordered TiO2/Au nanorod array was successfully fabricated by direct current electrodeposition and subsequent spin-coating. Scanning electron microscopy and transmission electron microscopy images revealed that the TiO2 film completely covered the surface of the Au nanorods, which resulted in TiO2 shell Au core nanorods. X-ray diffraction patterns revealed that the TiO2 film was anatase with preferential orientation in the (101) plane. UV-Vis diffuse reflectance spectra showed a shift in the absorption edge toward the visible region because of the formation of a Schottky junction between Au and TiO2. A new absorption peak that ranged from 400 to 800 nm appeared because of the localized surface plasmon resonance of the Au nanorod arrays. For the photocatalytic degradation of rhodamine B under UV light irradiation, the TiO2/Au nanorod array exhibited excellent photocatalytic activity and its kinetic constant was 2.0 times that of pristine TiO2 and 1.3 times that of a TiO2/Au film. The enhanced photocatalysis was attributed to the high surface volume ratio, an improved UV light response, efficient separation, and the convenient migration of photogenerated charge carriers because of the one-dimensional nanorod structure and the Schottky junction between Au and TiO2. This work could provide new insights into the fabrication of a high performance photocatalyst and thus facilitate practical environmental applications.

摘要采用电沉积和旋转涂膜相结合的方法成功制备了高度有序的 TiO2/Au 纳米棒阵列催化剂. 扫描电镜和透射电镜结果表明, TiO2 薄膜均匀地包覆在 Au 纳米棒的表面, 形成核壳型的一维阵列结构. X 射线衍射分析表明所获得 TiO2 为 (101) 晶面优先生长的锐钛矿晶相. 紫外-可见漫反射光谱显示, 由于 Au 和 TiO2 间肖特基结的存在造成吸收红移, Au 纳米棒表面的等离子共振效应导致 400∼800 nm 间出现吸收峰. 在紫外光催化降解罗丹明 B 反应中, TiO2/Au 纳米棒阵列催化剂表现出优异的催化活性, 其动力学常数分别为 TiO2 和 TiO2/Au 膜的 2.0 和 1.3 倍. 这主要归结于 Au 与 TiO2 间的肖特基结和一维阵列结构所带来的大的比表面积、宽的光响应范围和有效的光生载流子分离与传递.

A TiO2/Au nanorod array photocatalyst was found to combine the effects of a large surface area, improved UV light response, efficient separation, and convenient photogenerated charge carrier transfer while exhibiting efficient pollutant degradation.Figure optionsDownload as PowerPoint slide