Department of Physics and Materials Science, City University of Hong Kong, Hong Kong Special Administrative Region.
College of Science, China University of Petroleum, Qingdao, Shandong 266580, People's Republic of China.
J Colloid Interface Sci. 2017 Apr 15;492:167-175. doi: 10.1016/j.jcis.2017.01.001. Epub 2017 Jan 4.
A one-step hydrothermal method was adopted to synthesize the AgO/TiO nanoheterojunction. Its photocatalytic activity was evaluated by degrading methylene blue (MB) aqueous solution under UV and visible light. The MB degradation results showed that the AgO/TiO nanoheterojunction enhances the photocatalytic activity under UV irradiation rather than visible light. X-ray photoelectron spectroscopy (XPS) was performed to detect the electronic structure at the interface of AgO and TiO. The XPS results confirmed that the electronic band structure of the nanoheterojunction was determined by the interface states between the AgO and TiO interface. Thus, the photocatalytic enhancement mechanism can be ascribed to the creation of an additional potential barrier in the conduction band between AgO and TiO, which facilitates the transport of holes from TiO to AgO but inhibits the flow of electrons in the reverse direction unless sufficient potential energy is provided to overcome the additional barrier. Our results have provided a new insight on the role of interface states between the p-n nanojunction in the photocatalytic activity.
采用一步水热法合成了 AgO/TiO 纳米异质结。通过在紫外光和可见光下降解亚甲基蓝（MB）水溶液评价其光催化活性。MB 降解结果表明，AgO/TiO 纳米异质结对紫外光照射下的光催化活性有增强作用，而对可见光没有增强作用。采用 X 射线光电子能谱（XPS）检测 AgO 和 TiO 界面处的电子结构。XPS 结果证实，纳米异质结的能带结构由 AgO 和 TiO 界面的界面态决定。因此，光催化增强的机理可以归因于在 AgO 和 TiO 之间的导带中创建了一个附加的势垒，这有利于空穴从 TiO 到 AgO 的传输，但抑制电子在反向的流动，除非提供足够的势能来克服附加势垒。我们的结果为 p-n 纳米结界面在光催化活性中的作用提供了新的见解。
