Isotropic Iodide Adsorption Causes Anisotropic Growth of Copper Microplates
Isotropic Iodide Adsorption Causes Anisotropic Growth of Copper Microplates
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DOI：
10.1021/acs.chemmater.0c03596
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发表时间：
2021-02-09
影响因子：
8.6
通讯作者：
Wiley, Benjamin J.
中科院分区：
文献类型：
--
作者：
Kim, Myung Jun;Cruz, Mutya A.;Wiley, Benjamin J.
控制金属纳米结构的形状赠款控制其性质，但导致金属纳米结构的溶液相各向异性生长的过程尚未完全理解。这篇文章显示了为什么添加少量（75-100 μ M）的碘离子的铜纳米线合成的结果在形成的铜微板。微板是100 nm厚和微米宽的晶体，其被认为是通过原子添加到其侧面上的{100}面而不是其顶面和底面上的{111}面来生长。单晶电化学测量表明，碘离子的加入使Cu（111）的加成速率降低了8.2倍，这是由于碘离子取代了吸附的氯离子。同时，碘离子的加入使Cu（100）的Cu加成速率增加了4.0倍，这是由于用吸附的碘化物取代了十六胺（HDA）自组装单层。随着碘离子浓度的增加，{100}晶面的活化和{111}晶面的钝化与微孔板产量的增加相关。从头算热力学计算表明，在实验条件下，Cu（100）和Cu（111）上的碘离子取代了绝大多数氯离子和HDA.虽然预测和观察到Cu纳米线形成）在含有氯化物和HDA的溶液中，但计算表明，当存在少量碘化物时，对于{111}面（和微板）生长出现强的热力学驱动力，这与实验一致。
Control over the shape of a metal nanostructure grants control over its properties, but the processes that cause solution-phase anisotropic growth of metal nanostructures are not fully understood. This article shows why the addition of a small amount (75-100 mu M) of iodide ions to a Cu nanowire synthesis results in the formation of Cu microplates. Microplates are 100 nm thick and micronwide crystals that are thought to grow through atomic addition to {100} facets on their sides instead of the {111} facets on their top and bottom surfaces. Single-crystal electrochemical measurements show that the addition of iodide ions decreased the rate of Cu addition to Cu(111) by 8.2 times due to the replacement of adsorbed chloride by iodide. At the same time, the addition of iodide ions increased the rate of Cu addition to Cu(100) by 4.0 times due to the replacement of a hexadecylamine (HDA) self-assembled monolayer with the adsorbed iodide. The activation of {100} facets and passivation of {111} facets with increasing iodide ion concentration correlated with an increasing yield of microplates. Ab initio thermodynamics calculations show that, under the experimental conditions, a minority of iodide ions replaces an overwhelming majority of chloride and HDA on both Cu(100) and Cu(111). While Cu nanowire formation is predicted and observed) in solutions containing chloride and HDA, the calculations indicate that a strong thermodynamic driving force occurs for {111} facet (and microplate) growth when a small amount of iodide is present, consistent with the experiment.