Department of Chemistry, Duke University , 124 Science Drive, Box 90354, Durham, North Carolina 27708, United States.
School of Chemical and Biological Engineering, Seoul National University , Seoul 151-742, Republic of Korea.
J Am Chem Soc. 2017 Jan 11;139(1):277-284. doi: 10.1021/jacs.6b10653. Epub 2016 Dec 23.
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) 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.
金属纳米结构的合成通常需要使用封端剂，一般认为该封端剂通过阻止原子添加到特定晶面来导致各向异性生长。本工作使用一系列带有石英晶体微天平的电化学测量和单晶电极来阐明在 Cu 纳米线合成中发生的面选择性化学。与流行的假设相反，乙二胺，在 Cu 纳米线合成中被称为封端剂，通过增加生长纳米线末端（111）面相对于纳米线侧面（100）面的原子添加速率来导致各向异性生长。乙二胺通过选择性抑制 Cu(111)表面上 Cu 氧化物的形成，从而增加 Cu(OH) 在 Cu(111)表面上的还原速率，相对于 Cu(100)表面。这项工作展示了如何通过研究面选择性电化学来提高对原子组装形成各向异性金属纳米结构的过程的理解。
