Hot-Electron-Driven Interfacial Chemistry Using Non-Noble Plasmonic Cu under Visible-Light Irradiation

Plasmon-excitation-driven hot electrons have been demonstrated to initiate chemical transformations when exposed to visible light. Nevertheless, achieving six-electron plasmon photocatalysis remains both rare and challenging due to the inability to maintain the persistent utilization of hot electrons. Moreover, plasmonic photocatalysts predominantly rely on noble metal nanomaterials, such as gold (Au) and silver (Ag) nanostructures. In this study, we explore the plasmonic catalysis of six-electron chemistry utilizing non-noble copper (Cu) nanoparticles under visible-light irradiation. Intriguingly, our findings reveal that in the absence of chemical reducing agents, cost-effective Cu nanoparticles can effectively catalyze the plasmonic conversion of 4-nitrothiophenol to 4-aminothiophenol─a transformation that remains unattainable for noble Au and Ag nanoparticles under identical conditions. Drawing upon the insights gleaned from in situ surface-enhanced Raman spectroscopy, we postulate that interfacial water (H 2 O) molecules compensate for the energetic hot holes generated on the plasmonic Cu surface, thereby furnishing an adequate supply of hot electrons required to activate the six-electron photocatalytic reaction. This research showcases the feasibility of multielectron photocatalysis chemistry employing earth-abundant Cu nanoparticles, thereby presenting promising opportunities for efficient solar-to-chemical energy conversion.