Department of Chemistry, Wesleyan University, 52 Lawn Avenue, Middletown, Connecticut 06459, United States.
J Am Chem Soc. 2020 Dec 23;142(51):21322-21335. doi: 10.1021/jacs.0c07987. Epub 2020 Nov 25.
The synthesis of shaped metal nanoparticles to meet the precise needs of emerging applications requires intentional synthetic design directed by fundamental chemical principles. We report an integrated electrochemistry approach to nanoparticle synthetic design that couples current-driven growth of metal nanoparticles on an electrode surface-in close analogy to standard colloidal synthesis-with electrochemical measurements of both electrochemical and colloidal nanoparticle growth. A simple chronopotentiometry method was used to translate an existing colloidal synthesis for corrugated palladium (Pd) nanoparticles to electrochemical growth on a glassy carbon electrode, with minimal modification to the growth solution. The electrochemical synthesis method was then utilized to produce large Pd icosahedra, a shape whose synthesis is challenging in a colloidal growth environment. This electrochemical synthesis for Pd icosahedra was used to develop a corresponding colloidal growth solution by tailoring a weak reducing agent to the measured potential profile of the electrochemical synthesis. Finally, measurements of colloidal syntheses were employed as guides for the directed design of electrochemical syntheses for Pd cubes and octahedra. Together, this work provides a cyclical approach to shaped nanoparticle design that allows for the optimization of nanoparticles grown via a colloidal approach with a chemical reducing agent or synthesized with an applied current on an electrode surface as well as subsequent bidirectional translation between the two methods. The enhanced chemical flexibility and direct tunability of this electrochemical method relative to combinatorial design of colloidal syntheses have the potential to accelerate the synthetic design process for noble metal nanoparticles with targeted morphologies.
为满足新兴应用的精确需求而合成特定形状的金属纳米粒子，需要基于基本化学原理进行有针对性的合成设计。我们报告了一种综合电化学方法，用于纳米粒子合成设计，该方法将电极表面上金属纳米粒子的电流驱动生长（与标准胶体合成非常类似）与电化学测量相结合，同时测量电化学和胶体纳米粒子的生长。我们使用简单的恒电流计时法，将现有的波纹钯（Pd）纳米粒子胶体合成转化为在玻璃碳电极上的电化学生长，而对生长溶液的修改最小。然后，我们利用电化学合成方法来制备大的 Pd 二十面体，这是一种在胶体生长环境中难以合成的形状。这种 Pd 二十面体的电化学合成被用来开发相应的胶体生长溶液，通过调整弱还原剂来适应电化学合成的测量电位曲线。最后，我们将胶体合成的测量结果用作指导，以定向设计 Pd 立方体和八面体的电化学合成。总之，这项工作提供了一种循环方法来设计特定形状的纳米粒子，允许优化通过胶体方法使用化学还原剂生长的纳米粒子，或通过在电极表面施加电流合成的纳米粒子，以及随后在这两种方法之间进行双向转化。与胶体合成的组合设计相比，这种电化学方法具有增强的化学灵活性和直接可调节性，有可能加速具有目标形态的贵金属纳米粒子的合成设计过程。
