Ethylenediamine Promotes Cu Nanowire Growth by Inhibiting Oxidation of Cu(111)

• Published in: Journal of the American Chemical Society Vol. 139; no. 1; pp. 277 - 284
• Main Authors: Kim, Myung Jun, Flowers, Patrick F, Stewart, Ian E, Ye, Shengrong, Baek, Seungyeon, Kim, Jae Jeong, Wiley, Benjamin J
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 11.01.2017
• ISSN: 0002-7863; 1520-5126
• DOI: 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.