Synthesis of Composition-Tunable Ag-Cu Bimetallic Nanoparticles Through Plasma-Driven Solution Electrolysis

Bimetallic nanomaterials have shown great potential across various fields of application. However, the synthesis of many bimetallic particles can be challenging due to the immiscibility of their constituent metals. In this study, we present a synthetic strategy to produce compositionally tunable silver-copper (Ag-Cu) bimetallic nanoparticles using plasma-driven liquid surface chemistry. By using a low-pressure nonthermal radiofrequency (RF) plasma that interacts with an Ag-Cu precursor solution at varying electrode distances, we identified that the reduction of Ag and Cu salts is governed by two "orthogonal" parameters. The reduction of Cu²⁺ is primarily influenced by plasma electrons, whereas UV photons play a key role in the reduction of Ag⁺. Consequently, by adjusting the electrode distance and the precursor ratios in the plasma-liquid system, we could control the composition of Ag-Cu bimetallic nanoparticles over a wide range.