Koolen Cedric David, Torrent Laura, Agarwal Ayush, Meili-Borovinskaya Olga, Gasilova Natalia, Li Mo, Luo Wen, Züttel Andreas
Laboratory of Materials for Renewable Energy (LMER), Institute of Chemical Sciences and Engineering (ISIC), Basic Science Faculty (SB), École Polytechnique Fédérale de Lausanne (EPFL) Valais/Wallis, Energypolis, Sion 1951, Switzerland.
Empa Materials Science and Technology, Dübendorf 8600, Switzerland.
ACS Nano. 2022 Aug 23;16(8):11968-11978. doi: 10.1021/acsnano.2c01840. Epub 2022 Jul 25.
Nanoparticles (NPs) have wide applications in physical and chemical processes, and their individual properties (e.g., shape, size, and composition) and ensemble properties (e.g., distribution and homogeneity) can significantly affect the performance. However, the extrapolation of information from a single particle to the ensemble remains a challenge due to the lack of suitable techniques. Herein, we report a high-throughput single-particle inductively coupled plasma mass spectrometry (SP-ICP-MS)-based protocol to simultaneously determine the size, count, and elemental makeup of several thousands of (an)isotropic NPs independent of composition, size, shape, and dispersing medium with atomistic precision in a matter of minutes. By introducing highly diluted nebulized aqueous dispersions of NPs directly into the plasma torch of an ICP-MS instrument, individual NPs are atomized and ionized, resulting in ion plumes that can be registered by the mass analyzer. Our proposed protocol includes a phase transfer step for NPs synthesized in organic media, which are otherwise incompatible with ICP-MS instruments, and a modeling tool that extends the measurement of particle morphologies beyond spherical to include cubes, truncated octahedra, and tetrahedra, exemplified by anisotropic Cu NPs. Finally, we demonstrate the versatility of our method by studying the doping of bulk-dilute (<1 at. %) CuAg nanosurface alloys as well as the ease with which ensemble composition distributions of multimetallic NPs (i.e., CuPd and CuPdAg) can be obtained providing different insights in the chemistry of nanomaterials. We believe our combined protocol could deepen the understanding of macroscopic phenomena involving nanoscale structures by bringing about a statistics renaissance in research areas including, among others, materials science, materials chemistry, (nano)physics, (nano)photonics, catalysis, and electrochemistry.
纳米颗粒（NPs）在物理和化学过程中有着广泛应用，其个体性质（如形状、尺寸和组成）以及整体性质（如分布和均匀性）会显著影响性能。然而，由于缺乏合适的技术，从单个颗粒推断整体信息仍然是一项挑战。在此，我们报告了一种基于高通量单颗粒电感耦合等离子体质谱（SP-ICP-MS）的方法，可在几分钟内以原子精度同时测定数千个各向同性或各向异性纳米颗粒的尺寸、数量和元素组成，且不受组成、尺寸、形状和分散介质的影响。通过将高度稀释的纳米颗粒雾化水分散体直接引入电感耦合等离子体质谱仪的等离子体炬中，单个纳米颗粒被雾化和电离，产生可被质量分析仪记录的离子羽流。我们提出的方法包括一个相转移步骤，用于处理在有机介质中合成的、原本与电感耦合等离子体质谱仪不兼容的纳米颗粒，以及一个建模工具，该工具将颗粒形态的测量范围从球形扩展到包括立方体、截角八面体和四面体等，以各向异性铜纳米颗粒为例。最后，我们通过研究体相稀释（<1原子%）的铜银纳米表面合金的掺杂情况，以及获得多金属纳米颗粒（即铜钯和铜钯银）整体组成分布的难易程度，展示了我们方法的多功能性，为纳米材料化学提供了不同的见解。我们相信，我们的综合方法能够通过在材料科学、材料化学、（纳米）物理学、（纳米）光子学、催化和电化学等研究领域引发统计复兴，加深对涉及纳米级结构的宏观现象的理解。
