Abstract:

A simple, feasible and controllable method is presented to prepare uniform Au@TiO₂ nanotube arrays by depositing Au nanofilms on the top of the TiO₂ nanotube arrays via magnetron sputtering. The TiO₂ nanotube arrays is obtained using the anodization process at room temperature, followed by heat treatment at 450℃ in air for 2h. The heat treatment leads to the migration of Au atoms into TiO₂ nanotube arrays, resulting in the formation of the Au nanocrystals on the outer surface of the TiO₂, i.e. the Au@TiO₂ nanotube arrays. The microstructure of the prepared Au@TiO₂ nanotube arrays is characterized by using scanning electron microscopy, energy dispersive spectrometer, X-ray diffraction and transmission electron microscopy. Also, the emporal evolution of photocurrent response, photoluminescence emission spectrum, UV-vis diffuse reflection spectra and photodegration of the methylene blue are used to evaluate its photoelectric and photocatalytic properties. Compared with pure TiO₂ nanotube arrays, the Au@TiO₂ nanotube arrays catalysts have much higher photocatalytic activity in the aqueous methylene blue solution under visible light irradiation. Such behavior can be contributed to the enhanced electro-hole separation and the reduced recombination of them through the localized surface plasmon resonance (LSPR) of Au nanoparticles.

Key words: Au@TiO₂ nanotube arrays, Au nanoparticles, nanofilms preparation, anodization, magnetron sputtering, catalyst, photocatalytic property

摘要：

利用一种简单易行、可控的方法制备了均匀的Au@TiO₂纳米管阵列。首先在室温下通过阳极氧化的方法形成TiO₂纳米管，再在氧化后的TiO₂纳米管上用磁控溅射沉积不同厚度的Au膜，最后将沉积Au膜后的TiO₂纳米管在空气中450℃退火2h。热处理过程导致了Au向TiO₂纳米管的扩散，在纳米管表面形成了Au“岛”包裹的Au@TiO₂纳米管。对制备的Au@TiO₂纳米管的微观结构利用了扫描电子显微镜、能谱、X射线衍射和透射电子显微镜进行表征。并且用光电流、紫外可见光光漫反射光谱、荧光光谱和降解亚甲基蓝溶液的方法分析测量了Au@TiO₂纳米管的光电性能及光催化性能。结果表明：当可见光照射含Au@TiO₂纳米管催化剂的亚甲基蓝水溶液时，其光催化性能远远高于纯TiO₂纳米管，这是由于Au颗粒表面等离子体共振效应（LSPR）增加了电子-空穴对的分离并且延缓了其重组所致。

关键词: Au@TiO₂纳米管, Au纳米粒子, 纳米薄膜制备, 阳极氧化, 磁控溅射, 催化剂, 光催化性能