One-step synthesis of monodisperse Au–Ag alloy nanoparticles in a microreaction system

Monodisperse Au–Ag alloy nanoparticles were synthesized by a one-step rapid injection method in a capillary microreaction system with a short residence time (less than 3 min). Au–Ag alloy NPs possessed homogenous composition that revealed a linear relationship with surface plasmon resonance absorption peak. The optimal size distribution of Au–Ag alloy NPs with a standard deviation of 6% could be obtained from decreasing the molar ratio of Au3+:Ag+ from 1:10 to 1:20 or enhancing the synthesis temperature from 140 to 160 °C. Transmission electron micrographs showed as-obtained Au–Ag alloy nanoparticles were sphere-like with the smallest average size of only 2.7 nm.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Monodisperse Au–Ag alloy nanoparticles were synthesized via a capillary microreaction system. ► The raw materials were introduced into the system by a one-step rapid injection method. ► The synthesis time was very short less than 3 min. ► Au–Ag alloy nanoparticles possessed homogenous composition and small size (2.7 nm). ► The optimal size distribution of Au–Ag alloy nanoparticles had only a standard deviation of 6%.