Interface engineering to enhance the oxygen evolution reaction under light irradiation

Using a combination of plasmonic metal cores (Ag, Au, and Cu) and catalytic metal/semiconductor shells is a viable approach to enhance photocatalytic chemical reactions such as the oxygen evolution reaction (OER). However, the energy transfer mechanism between the plasmonic core and the catalytic shell as well as the functional mechanism of plasmon in the OER reactions is still unclear. Here, we designed core-shell Au@Ni₃S₂ and yolk-shell Au-Ni₃S₂ with well-controlled morphology. We directly mapped the distribution of plasmon using monochromatic low-loss electron energy loss spectroscopy. The structural pore in the yolk-shell Au-Ni₃S₂ greatly changes the dielectric environment and significantly enhances absorption of incoming light. The incoming photoenergy was dominantly dissipated on the shell by forming electron-hole pairs, leading to a higher energy flow rate for OER reactions. The catalytic activity of yolk-shell Au-Ni₃S₂ achieved nearly sixfold of core-shell Au@Ni₃S₂ and over 80-fold of pure Ni₃S₂ under illumination. Our results suggest that delicate microstructural control of catalysts can be used as an effective approach to design more efficient catalysts.