Two‐Dimensional Plasmonic Hot Spots Engineering for Photocatalysis

Plasmonic nanostructures can generate hot carriers (electrons and holes) that are powerful for converting solar energy into chemical energy by using low‐energy photons. However, this conversion efficiency still remains too limited to satisfy practical applications. One way to improve conversion efficiency is to accelerate the hot carrier generation. Introducing nanogaps into plasmonic nanostructures has demonstrated an efficient way to generate “hot spots” where the localized electric field is extensively enlarged. Such hot spot areas further improve the hot carrier generation efficiency. In this work, we design 2D plasmonic nanosheets that form hot spots over a wide 2D range. Fano resonances are observed in the 2D plasmonic nanosheets, which contribute to enhancing the localized electric field. The small‐gapped 2D nanosheets demonstrate a prominent Fano resonance and a largely enhanced electric field within the nanogaps, accelerating the hot electron generation. We further observe a low charge transfer resistance on the surface of the small‐gapped 2D nanosheets. These two factors consequently contribute to a high photocatalytic rate. The stable 2D nanosheets with the engineerable hot spots indicate a new design for the high‐efficiency plasmonic photocatalysts.