From Batch to Flow Plasmon Catalysis: Revealing Mass Transport Limits in Au@Pd Nanocatalysts for Suzuki Coupling

Abstract

Plasmonic catalysis, as a powerful tool for synthetic transformations, has the potential to impact wide-scale applications by converting solar light into energy for chemical reactions. Current studies are limited to mL-scale batch reactors with mg-level nanocatalysts, lacking feasibility at common laboratory and industrially configurations. To overcome this limitation, transition of plasmonic chemistry from batch to flow mode is foreseen, however, there is a lack of understanding of how plasmon-driven processes couple with mass transport. To address this, we designed plasmonic catalysts for a flow system within tens of mL scale employing gram-scale Au@PdNPs-Al2O3 nanostructures in a flow reactor. Using Suzuki cross-coupling as a model reaction, we showed that flow mode for Au@PdNPs-Al2O3 increases reaction rate, time to full conversion and apparent quantum yield (AQY) ×3 times compared to batch mode and overperform previously reported ones. Fluid dynamic simulations showed critical effect of residence times of nanocatalyst–reactant complexes under illumination to product yield. This was consistent with photocurrent measurements, revealing electron transfer efficiency is enhanced under increased mass transport conditions. Unlike prior studies that primarily emphasized the carrier dynamic within metal–metal/semiconductor heterojunctions (e.g., Au/Pd) in batch mode, our flow system demonstrates that efficient carrier transfer to reactants is critical for achieving high TON and AQY. This work provides the first framework for translating plasmonic catalysis into flow, offering design principles for future light-driven chemical processes beyond conventional batch mode.