Tracing the Origin of Visible Light Enhanced Oxygen Evolution Reaction

Hybrid nanostructures with a plasmonic core and catalytic shell often show significantly enhanced catalytic efficiency under illumination of specific frequency. Excitation of localized surface plasmonic resonance on plasmonic metals under illumination can generate hot electrons that assist in the catalytic reaction. However, the correlation between the microstructural geometry, dielectric environment, internal energy flow in the hybrid structure, and the chemical reaction rate is so far not clear. Here, a composite with a plasmonic Au metal yolk and a nearly transparent Ni3S2 shell is designed to maximize the absorption of incident light by forming strong localized surface plasmonic resonance at the yolk as predicted by 3D finite element method. The incoming photoenergy is dominantly dissipated on the shell by forming electron-hole pairs, leading to higher energy flow rate for oxygen evolution reaction. The overpotential is 252 mV at 10 mA cm(-2) and the catalytic activity of Au@Ni3S2 achieves ca. 85-fold that of pure Ni3S2 under illumination and surpasses the commercial IrO2 catalyst. The study opens the door of exploration of highly effective hybrid composite catalysts for energy applications.