Department of Physics, School of Science, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, People's Republic of China.
Nanotechnology. 2019 Feb 22;30(8):085708. doi: 10.1088/1361-6528/aaf197. Epub 2018 Nov 16.
Au doped ZnO nanocomposite films on TiO seeding layer (AuZ/T) were fabricated by hydrothermal processing and their photocatalytic performance was investigated. It could be found that the AuZ/T with micrometer(μm)-sized, lying ZnO bulks revealed optimal photocatalytic performance toward methyl orange under simulated sunlight, whose apparent degradation rate constant K of 1.31 was about 20% higher compared to that of ZnO/TiO and 3 times higher compared to that of ZnO. The Au nanoparticles, TiO seeding layer and hydrothermal processing time imposed vital influence on the morphology of ZnO nanostructures, which played key roles in the formation of ZnO/TiO heterojunction and charge transfer (CT) inside it, as demonstrated by kinetics of transient photoluminescence (PL) decaying. The incorporation of Au nanoparticles not only induced the variations of ZnO crystallinity and reduction of ZnO band gap (E ), but also generated the Schottky heterojunction of metal-semiconductor, which would be beneficial to the CT inside nanocomposite films and separation of photo-generated electron-hole pairs, as verified by the remarkable PL suppression. The mechanism responsible for photocatalysis enhancement, which was resulted from the hybrid effects of Au nanoparticles and the ZnO morphology was discussed in details.
在 TiO2 种子层上制备了掺金 ZnO 纳米复合薄膜（AuZ/T），并研究了其光催化性能。可以发现，具有微米（μm）级、平躺 ZnO 块状结构的 AuZ/T 在模拟阳光下对甲基橙表现出最佳的光催化性能，其表观降解速率常数 K 为 1.31，比 ZnO/TiO2 提高了约 20%，比 ZnO 提高了 3 倍。金纳米粒子、TiO2 种子层和水热处理时间对 ZnO 纳米结构的形态有重要影响，这在 ZnO/TiO2 异质结的形成和其中的电荷转移（CT）中起着关键作用，这可以通过瞬态光致发光（PL）衰减的动力学来证明。金纳米粒子的掺入不仅引起 ZnO 结晶度的变化和 ZnO 带隙（Eg）的降低，而且还产生了金属半导体的肖特基异质结，这有利于纳米复合薄膜内的 CT 和光生电子-空穴对的分离，这可以通过显著的 PL 抑制来验证。详细讨论了光催化增强的机制，这是由于 Au 纳米粒子和 ZnO 形态的混合效应所致。
