The electrodeposition of gold nanoparticles from aqueous nanodroplets
The electrodeposition of gold nanoparticles from aqueous nanodroplets
复制标题
DOI：
10.1039/d2cc03645b
复制
发表时间：
2022-07-19
影响因子：
4.9
通讯作者：
Dick, Jeffrey E.
中科院分区：
文献类型：
--
作者：
Reyes-Morales, Joshua;Moazeb, Mohamed;Dick, Jeffrey E.
纳米液滴介导电沉积是一种可靠的电沉积方法，通过将少量的金属盐前驱体限制在悬浮在油连续相中的纳米水滴(半径约为400 nm)中。这项技术在纳米颗粒的尺寸、形貌和孔隙率方面提供了巨大的优势。为了使电化学反应在纳米水滴中进行，必须保持电中性条件。传统上，[Nb4][ClO4]或类似的盐被添加到油的连续相中以保持电荷平衡。不幸的是，这种盐在油相中的存在会导致一些金属盐，如HAuCl4，发生相转移，从而阻止金纳米颗粒的形成。在这里，我们用电感耦合等离子体质谱(ICP-MS)证明，当LiClO4被添加到纳米液滴相中而[NBu4][ClO4]没有被添加到连续相中时，HAuCl4的分配比在纳米液滴相中添加LiCl4时低几个数量级。这种简单的改变允许金纳米颗粒的电沉积。扫描电子显微镜显示了在不同LiClO4浓度下得到的金纳米颗粒的形貌和尺寸分布。在选定的衍射模式下使用了透射电子显微镜，结果表明所得到的金纳米粒子是多晶金，其米勒指数分别为222和200。这项工作拓宽了可从纳米液滴电沉积的纳米颗粒的种类，用于能量存储和转换、光电化学和生物传感。
Nanodroplet-mediated electrodeposition is a reliable method for electrodepositing nanoparticles by confining a small amount of metal-salt precursor in water nanodroplets (radius similar to 400 nm) suspended in an oil continuous phase. This technique provides a great advantage in terms of nanoparticle size, morphology, and porosity. For an electrochemical reaction to proceed in the aqueous nanodroplet, the electroneutrality condition must be maintained. Classically, [NB4][ClO4] or a comparable salt is added to the oil continuous phase to maintain charge balance. Unfortunately, the presence of this salt in the oil phase causes some metal salts, such as HAuCl4, to phase transfer, disallowing the formation of gold nanoparticles. Here, we demonstrate the partitioning of HAuCl4 is orders of magnitude lower using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) when LiClO4 is added to the nanodroplet phase and [NBu4][ClO4] is not added to the continuous phase. This simple change allows for the electrodeposition of gold nanoparticles. Scanning electron microscopy shows the morphology and size distribution of gold nanoparticles obtained at different concentrations of LiClO4. Transmission electron microscopy in selected diffraction mode was used and it determined the gold nanoparticles obtained are polycrystalline with miller indices of (222) and (200). This work widens the variety of nanoparticles that can be electrodeposited from nanodroplets for applications in energy storage and conversion, photoelectrochemistry, and biosensing.