Nanomaterials and Environmental Detection Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei 230031, People's Republic of China.
ACS Appl Mater Interfaces. 2014 Aug 13;6(15):12203-13. doi: 10.1021/am501617a. Epub 2014 Jul 18.
This study attempts to understand the intrinsic impact of different morphologies of nanocrystals on their electrochemical stripping behaviors toward heavy metal ions. Two differently shaped Fe3O4 nanocrystals, i.e., (100)-bound cubic and (111)-bound octahedral, have been synthesized for the experiments. Electrochemical results indicate that Fe3O4 nanocrystals with different shapes show different stripping behaviors toward heavy metal ions. Octahedral Fe3O4 nanocrystals show better electrochemical sensing performances toward the investigated heavy metal ions such as Zn(II), Cd(II), Pb(II), Cu(II), and Hg(II), in comparison with cubic ones. Specifically, Pb(II) is found to have the best stripping performance on both the (100) and (111) facets. To clarify these phenomena, adsorption abilities of as-prepared Fe3O4 nanocrystals have been investigated toward heavy metal ions. Most importantly, combined with theoretical calculations, their different electrochemical stripping behaviors in view of facet effects have been further studied and enclosed at the level of molecular/atom. Finally, as a trial to find a disposable platform completely free from noble metals, the potential application of the Fe3O4 nanocrystals for electrochemical detection of As(III) in drinking water is demonstrated.
本研究旨在深入了解纳米晶体不同形态对其电化学剥离行为的内在影响。我们合成了两种不同形态的 Fe3O4 纳米晶体，即（100）面结合的立方和（111）面结合的八面体，用于实验。电化学结果表明，不同形态的 Fe3O4 纳米晶体对重金属离子表现出不同的剥离行为。与立方 Fe3O4 纳米晶体相比，八面体 Fe3O4 纳米晶体对所研究的重金属离子如 Zn(II)、Cd(II)、Pb(II)、Cu(II)和 Hg(II)表现出更好的电化学传感性能。具体来说，Pb(II)在（100）和（111）晶面上都表现出最好的剥离性能。为了阐明这些现象，我们研究了制备的 Fe3O4 纳米晶体对重金属离子的吸附能力。最重要的是，结合理论计算，我们进一步研究了它们在晶面效应方面的不同电化学剥离行为，并在分子/原子水平上进行了总结。最后，作为寻找完全不含贵金属的一次性平台的尝试，我们展示了 Fe3O4 纳米晶体在饮用水中电化学检测 As(III)的潜在应用。
