Key Laboratory of Micro-Nano Materials for Energy Storage and Conversion of Henan Province, Institute of Surface Micro and Nano Materials, Xuchang University , Henan 461000, P. R. China.
J Am Chem Soc. 2014 Jan 15;136(2):750-7. doi: 10.1021/ja410800y. Epub 2013 Dec 30.
Semiconductor nanostructures with photocatalytic activity have the potential for many applications including remediation of environmental pollutants and use in antibacterial products. An effective way for promoting photocatalytic activity is depositing noble metal nanoparticles (NPs) on a semiconductor. In this paper, we demonstrated the successful deposition of Au NPs, having sizes smaller than 3 nm, onto ZnO NPs. ZnO/Au hybrid nanostructures having different molar ratios of Au to ZnO were synthesized. It was found that Au nanocomponents even at a very low Au/ZnO molar ratio of 0.2% can greatly enhance the photocatalytic and antibacterial activity of ZnO. Electron spin resonance spectroscopy with spin trapping and spin labeling was used to investigate the enhancing effect of Au NPs on the generation of reactive oxygen species and photoinduced charge carriers. Deposition of Au NPs onto ZnO resulted in a dramatic increase in light-induced generation of hydroxyl radical, superoxide and singlet oxygen, and production of holes and electrons. The enhancing effect of Au was dependent on the molar ratio of Au present in the ZnO/Au nanostructures. Consistent with these results from ESR measurements, ZnO/Au nanostructures also exhibited enhanced photocatalytic and antibacterial activity. These results unveiled the enhanced mechanism of Au on ZnO and these materials have great potential for use in water purification and antibacterial products.
具有光催化活性的半导体纳米结构在许多应用中具有潜力，包括环境污染物的修复和抗菌产品的使用。提高光催化活性的一种有效方法是将贵金属纳米颗粒 (NPs) 沉积在半导体上。在本文中，我们成功地将尺寸小于 3nm 的 Au NPs 沉积到 ZnO NPs 上。合成了具有不同 Au/ZnO 摩尔比的 ZnO/Au 杂化纳米结构。结果发现，即使 Au/ZnO 的摩尔比非常低（0.2%），Au 纳米组件也可以大大提高 ZnO 的光催化和抗菌活性。采用电子顺磁共振波谱与自旋捕获和自旋标记相结合的方法研究了 Au NPs 对活性氧物种和光生载流子生成的增强作用。Au NPs 沉积到 ZnO 上会导致羟基自由基、超氧自由基和单线态氧的光诱导生成以及空穴和电子的产生显著增加。Au 的增强效果取决于 ZnO/Au 纳米结构中存在的 Au 的摩尔比。与 ESR 测量结果一致，ZnO/Au 纳米结构还表现出增强的光催化和抗菌活性。这些结果揭示了 Au 对 ZnO 的增强机制，这些材料在水净化和抗菌产品方面具有很大的应用潜力。
