AbstractThe structure–function relationship of plasmon‐enhanced electrochemistry (PEEC) is of great importance for the design of efficient PEEC catalysts, but is rarely investigated at single nanoparticle level for the lack of an efficient nanoscale methodology. Herein, we report the utilization of nanoparticle impact electrochemistry to allow single nanoparticle PEEC, where the effect of incident light on the plasmonic Ag/Au nanoparticles for accelerating cobalt metal–organic framework nanosheets (Co‐MOFNs) catalyzed hydrogen evolution reaction (HER) is systematically explored. It is found that the plasmon‐excited hot carrier injection can lower the reaction activation energy, resulting in a much promoted reaction probability and the integral charge generated from individual collisions. Besides, a plasmonic nanoparticle filtering method is established to effectively distinguish different plasmonic nanoparticles. This work provides a unique view in understanding the intrinsic physicochemical properties for PEEC at the nano‐confined domains.