Construction of Spatially Separated Gold Nanocrystal/Cuprous Oxide Architecture for Plasmon-Driven CO₂ Reduction

Plasmonic hot electrons have shown great potential in photocatalysis, but little is known about the hot hole-driven chemical reactions due to the lack of desired plasmonic metal/p-type semiconductor architectures. Herein, we describe a general and robust strategy for the site-selective growth of a p-type semiconductor, Cu₂O on Au nanocrystals (NCs), to produce diverse spatially separated Au/Cu₂O heterostructures. The preferential growth of Cu₂O on the tips/ends/edges of Au NCs is directed by the sparse coverage of the surfactant molecules at the high-curvature sites of Au NCs. The obtained dumbbell-shaped nanostructures serve as the ideal platforms for probing the hot-hole-mediated CO₂ reduction reaction. Benefiting from the hot-hole injection, a new reaction pathway is unlocked, and the C₂ product activity and selectivity are significantly improved. This study demonstrates the genuine superiority of the dumbbell-shaped nanostructures in photocatalysis, offering a new unique avenue to explore the underlying mechanism of hot-hole-mediated chemical reactions.