In this study, a facile and nontoxic synthetic method of well-covered Cu-Ag core-shell nanoparticles (Cu@Ag NPs) was determined. Through chemical reduction reaction in a modified silver ammonia solution with gelatin additive, the as-synthesized Cu@Ag NPs showed attractive comprehensive characteristics, including small and narrow size distribution, low proportion of Ag, dense and uniform Ag shell, good dispersibility, good sphericity, and desirable oxidation resistance. Based on electrochemical analysis, a complexing model was proposed to explain the effects of gelatin on the deposition of Ag. It revealed that the gelatin acted as not only the steric hindrance but also the complexing agent and diffusivity modifier. The gelatin addition could increase the stability and decrease the decoupling rate of complexed Ag ions, thus leading to significant negative shift of the deposition potential and decrease of the deposition rate, promoting the formation of finer and thinner Ag shell. Our study proposes an applicable approach for the synthesis of Cu@Ag core-shell nanoparticles, and the complexing model can provide a theoretical tool to describe the effects of complexing agent on the synthesis of Cu@Ag and other bimetallic nanoparticles.

中文翻译：

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从络合模型了解覆盖良好的 Cu-Ag 核壳纳米颗粒的简单合成


在本研究中，确定了一种简单无毒的 Cu-Ag 核壳纳米颗粒 （Cu@Ag NPs） 合成方法。通过在添加明胶添加剂的改性银氨溶液中进行化学还原反应，合成的Cu@Ag NPs表现出令人瞩目的综合特性，包括粒径分布小而窄、Ag比例低、Ag壳致密均匀、分散性好、球形性好、抗氧化性好。基于电化学分析，提出了一个络合模型来解释明胶对 Ag 沉积的影响。结果表明，明胶不仅起空间位阻的作用，还起络合剂和扩散调节剂的作用。明胶的添加可以提高络合 Ag 离子的稳定性并降低其解耦速率，从而导致沉积电位的显著负向偏移和沉积速率降低，从而促进更细、更薄的 Ag 壳的形成。本研究提出了一种适用于Cu@Ag核壳纳米颗粒合成的方法，络合模型可以为描述络合剂对Cu@Ag和其他双金属纳米颗粒合成的影响提供理论工具。