Sustaining high-energy hot carriers in plasmonic metals remains a central challenge for multi-electron photocatalytic transformations due to rapid hot-carrier recombination. Here, we demonstrate that crystal-facet engineering of semiconductor supports provides an effective strategy to regulate interfacial electron–hole compensation in plasmonic heterostructures. By constructing Au nanoparticles on SnO2 nanooctahedra dominantly exposing either 111 or 332 facets, we reveal that the 332 facet promotes more efficient interfacial electron injection into plasmonically excited Au, enabling effective compensation of hot holes and thereby sustaining the hot-electron population. In situ surface-enhanced Raman scattering (SERS) spectroscopy, kinetic analysis, and photoelectron spectroscopy collectively show that Au-SnO2332 drives the complete six-electron reduction of 4-nitrothiophenol under near-infrared excitation with a rate constant 6. 6 times higher than that of Au-SnO2111. Power- and wavelength-dependent studies further confirm that the enhanced activity originates from facet-governed hot-carrier dynamics rather than photothermal or direct semiconductor excitation effects. Energy-level alignment analysis indicates that the 332 facet provides more favorable energetics for electron transfer to neutralize plasmon-generated hot holes, thereby mitigating recombination losses. These findings establish interfacial electron–hole compensation as a decisive parameter in plasmonic multi-electron catalysis and identify crystal facet engineering as a general design principle for sustaining hot carriers in metal–semiconductor nanostructures.
Sun et al. (Tue,) studied this question.