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-aminothiophenola 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 (H2O) 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.