Robust, non-fouling liters-per-day flow synthesis of ultra-small catalytically active metal nanoparticles in a single-channel reactor

In this communication, we demonstrate the robust, non-fouling continuous synthesis of catalytically active palladium nanoparticles using a triphasic segmented flow in a hybrid milli–meso flow reactor, which not only allows us to completely eliminate fouling over extended operational duration, but also allows the achievement of ∼10 L per day volumetric productivity in a single-channel reactor. From the synthesis perspective, we select the harshest challenge for this demonstration – the aqueous flow synthesis of metal nanoparticles using the strong, gas-evolving reducing agent sodium borohydride. We also present comparative evaluations of the catalytic activities of flow-synthesized nanoparticles compared to their batch counterparts in a model hydrogenation reaction to highlight the consistency and quality of the nanoparticles produced by the scaled-up flow synthesis.