Defining Rules for the Shape Evolution of Gold Nanoparticles
Defining Rules for the Shape Evolution of Gold Nanoparticles
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DOI：
10.1021/ja305245g
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发表时间：
2012-09-05
影响因子：
15
通讯作者：
Mirkin, Chad A.
中科院分区：
文献类型：
--
作者：
Langille, Mark R.;Personick, Michelle L.;Mirkin, Chad A.
研究了银离子和卤化物（氯化物、溴化物和碘化物）在种子介导的金纳米结构合成中的作用，并确定了它们对10类形状不同的纳米颗粒生长的影响。我们系统地研究了每种化学成分对颗粒形状、颗粒形成速率和颗粒表面化学组成的影响。我们证明，卤化物可用于（1）调节溶液中金离子物种的还原电位和（2）钝化金纳米颗粒表面，这两者都控制反应动力学，从而能够选择性合成一系列不同的颗粒形状。我们还表明，银离子可以用作欠电位沉积剂，通过控制所得的金纳米粒子的生长，通过表面钝化（比动力学效应），以访问一组不同的颗粒形状。重要的是，我们表明可以通过溶液中存在的卤化物的数量和类型来控制银覆盖的密度。该行为起因于在较大卤化物存在下，由于Ag+/Ag-0-卤化物和Au+/Au-0-卤化物相互作用的相对强度以及卤化物在金颗粒表面上的钝化效应，欠电位沉积的银层的稳定性降低。我们总结了这项工作，提出了一套设计考虑，通过明智地使用卤化物和银离子的种子介导的合成制备的金纳米粒子的生长和最终形状控制。
The roles of silver ions and halides (chloride, bromide, and iodide) in the seed-mediated synthesis of gold nanostructures have been investigated, and their influence on the growth of 10 classes of nanoparticles that differ in shape has been determined. We systematically studied the effects that each chemical component has on the particle shape, on the rate of particle formation, and on the chemical composition of the particle surface. We demonstrate that halides can be used to (1) adjust the reduction potential of the gold ion species in solution and (2) passivate the gold nanoparticle surface, both of which control the reaction kinetics and thus enable the selective synthesis of a series of different particle shapes. We also show that silver ions can be used as an underpotential deposition agent to access a different set of particle shapes by controlling growth of the resulting gold nanoparticles through surface passivation (more so than kinetic effects). Importantly, we show that the density of silver coverage can be controlled by the amount and type of halide present in solution. This behavior arises from the decreasing stability of the underpotentially deposited silver layer in the presence of larger halides due to the relative strengths of the Ag+/Ag-0-halide and Au+/Au-0-halide interactions, as well as the passivation effects of the halides on the gold particle surface. We summarize this work by proposing a set of design considerations for controlling the growth and final shape of gold nanoparticles prepared by seed-mediated syntheses through the judicious use of halides and silver ions.