Continuous high-flux synthesis of gold nanoparticles with controllable sizes: a simple microfluidic system

Noble metal nanoparticles (NPs) have potential for use in many optical and electronic applications due to their shape- and size-dependent properties. However, it remains a significant challenge to synthesize size- and shape-controlled NPs on a large scale while maintaining their unique properties. We have demonstrated a simple and effective microreactor based on a microfluidic chip and liquid peristaltic pump for the synthesis of monodispersed Au NPs. This reactor allows for the continuous high-flux synthesis of Au NPs with precisely controlled sizes. The effects of reaction temperature, reaction time, flow ratio of the two inlets, and amount of surfactant agent are investigated in this study. The uniform and ultrafine Au NPs were synthesized by directly controlling the temperature, flow rate, surfactant concentration, and flow rate ratio. Moreover, the Au NPs are fabricated controllably, continuously, and stably on a large scale with this system. The proposed system thus contributes to the large-scale industrial production of NPs.