Key Laboratory of Environmental Optics and Technology, and Institute of Intelligent Machines, Chinese Academy of Sciences , Hefei 230031, People's Republic of China.
University of Science and Technology of China , Hefei 230026, People's Republic of China.
Anal Chem. 2018 Jan 16;90(2):1263-1272. doi: 10.1021/acs.analchem.7b04025. Epub 2017 Dec 22.
Nanocrystals generally suffer from agglomeration because of the spontaneous reduction of the system surface energy, resulting in blocking the active sites from reacting with target ions, and then severely reducing the electrochemical sensitivity. In this article, a highly ordered self-assembled monolayer array is successfully constructed using ∼14 nm CoFeO nanocubes uniformly and controllably distributed on the surface of a working electrode (glass carbon plate). The large area and high exposure of the surface defects on CoFeO nanocubes are clearly characterized by high-resolution transmission electron microscopy (HRTEM) and atomic-resolution high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM). Expectedly, a considerable sensitivity of 2.12 μA ppb and a low limit of detection of 0.093 ppb are achieved for As(III) detection on this highly homogeneous sensing interface; this excellent electroanalysis performance is even better than that of noble metals electrodes. Most importantly, this approach of uniformly distributing the small-sized defective nanoparticles on the electrode surface provides a new opportunity for modifying the electrodes, as well as the realization of their applications in the field of environmental electroanalysis for heavy metal ions.
由于系统表面能的自发降低，纳米晶通常会发生团聚，从而阻塞活性位与目标离子的反应，进而严重降低电化学灵敏度。在本文中，通过在工作电极（玻碳电极）表面均匀且可控地分布约 14nm 的 CoFeO 纳米立方体，成功构建了高度有序的自组装单层阵列。高分辨率透射电子显微镜（HRTEM）和原子分辨率高角度环形暗场扫描透射电子显微镜（HAADF-STEM）清楚地表征了 CoFeO 纳米立方体表面大面积和高暴露的表面缺陷。在这种高度均匀的传感界面上，对 As(III) 的检测实现了相当高的灵敏度 2.12μA ppb 和低检测限 0.093 ppb；这种优异的电分析性能甚至优于贵金属电极。最重要的是，这种在电极表面均匀分布小尺寸缺陷纳米颗粒的方法为修饰电极提供了新的机会，也为它们在重金属离子环境电分析领域的应用提供了可能。
