Abstract The synthesis of nanoparticles by reaction of liquid aerosol droplets containing precursors in a flow-through, atmospheric-pressure, non-thermal plasma offers a continuous, scalable, substrate- and stabilizer-free approach for direct deposition into liquids or onto soft substrates. However, the combination of multiphase and non-equilibrium chemistry makes the process complicated and poorly understood. Here, we present ion mobility spectrometry measurements of liquid water droplets containing silver nitrate passing through an atmospheric-pressure dielectric barrier discharge reactor that allows us to monitor silver nanoparticle formation online for the first time. Mobility diameter distributions were obtained with the plasma on and off, and exhibited a shift, which was related to the degree of conversion of silver nitrate. The silver nanoparticles were also collected and characterized by UV–visible absorbance spectroscopy and transmission electron microscopy to support the online measurements. Importantly, negligible conversion was found when the water was removed by a diffusion dryer, suggesting that the key reducing species are in the liquid phase, such as solvated electrons. Overall, the study demonstrates how ion mobility spectrometry measurements can be applied to provide insight into this approach to nanoparticle synthesis.

中文翻译：

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通过非热等离子体转化液态气溶胶液滴中金属盐形成纳米颗粒的在线离子迁移谱分析

摘要 通过含有前体的液态气溶胶液滴在流通、大气压、非热等离子体中反应合成纳米颗粒，提供了一种连续、可扩展、无基材和无稳定剂的方法，用于直接沉积到液体中或软基材上。然而，多相和非平衡化学的结合使该过程变得复杂且知之甚少。在这里，我们展示了含有硝酸银的液态水滴通过大气压介质阻挡放电反应器的离子迁移谱测量，这使我们能够首次在线监测银纳米颗粒的形成。流动性直径分布是在等离子体开启和关闭时获得的，并表现出与硝酸银转化程度有关的偏移。银纳米粒子也被收集并通过紫外可见吸收光谱和透射电子显微镜进行表征，以支持在线测量。重要的是，当通过扩散干燥器去除水时，发现转化率可以忽略不计，这表明关键的还原物质在液相中，例如溶剂化电子。总体而言，该研究展示了如何应用离子迁移谱测量来深入了解这种纳米颗粒合成方法。如溶剂化电子。总体而言，该研究展示了如何应用离子迁移谱测量来深入了解这种纳米颗粒合成方法。如溶剂化电子。总体而言，该研究展示了如何应用离子迁移谱测量来深入了解这种纳米颗粒合成方法。