Ethylenediamine Promotes Cu Nanowire Growth by Inhibiting Oxidation of Cu(111)
Kim, M. J., Flowers, P. F., Stewart, I. E., Ye, S., Baek, S., Kim, J. J., & Wiley, B. J. (2017). Ethylenediamine Promotes Cu Nanowire Growth by Inhibiting Oxidation of Cu(111). Journal of the American Chemical Society, 139(1), 277-284. Advance online publication. https://doi.org/10.1021/jacs.6b10653
The synthesis of metal nanostructures usually requires a capping agent that is generally thought to cause anisotropic growth by blocking the addition of atoms to specific crystal facets. This work uses a series of electrochemical measurements with a quartz crystal microbalance and single-crystal electrodes to elucidate the facet-selective chemistry occurring in the synthesis of Cu nanowires. Contrary to prevailing hypotheses, ethylenediamine, a so-called capping agent in the synthesis of Cu nanowires, causes anisotropic growth by increasing the rate of atomic addition to (111) facets at the end of a growing nanowire relative to (100) facets on the sides of a nanowire. Ethylenediamine increases the reduction rate of Cu(OH)(2)(-) on a Cu(111) surface relative to Cu(100) by selectively inhibiting the formation of Cu oxide on Cu(111). This work demonstrates how studying facet-selective electrochemistry can improve the understanding of the processes by which atoms assemble to form anisotropic metal nanostructures.