Temperature Effects on Ag Nanoparticle Array-Monolayer WS ₂ Composites for Plasmon-Driven Reduction of 4-Nitrothiophenol

Metal-WS2 nanocomposites show excellent potential in numerous applications, especially in plasmon-driven catalysis reactions. Here, a WS2-covered Ag nanoparticle array was fabricated by transferring WS2 onto the Ag nanoparticle (NP) array through a wet etching method. This composite was then utilized to in situ monitor the catalytic reaction of 4-nitrobenzenethiol to p, p′-dimercaptoazobenzene. Compared with the Ag NP array alone, the composite structure demonstrated enhanced catalytic performance. The catalytic performance of the composite was further enhanced by optimizing the annealing temperature. This enhancement is attributed to a synergistic effect: annealing transforms the Ag NP morphology and induces conformal wrinkling of WS2, which collectively enhance the exciton–plasmon coupling strength (quantified by a Rabi splitting of 90 meV). The strong coupling, combined with favorable interfacial energy alignment, maximizes the generation and transfer of plasmon-driven hot electrons to drive the molecular reduction reaction. These findings provide an attractive strategy for enhancing catalytic efficiency through interfacial engineering in composite plasmonic systems.