Photo‐assisted electrochemical hydrogen evolution by plasmonic Ag nanoparticle/nanorod heterogeneity

Abstract Transition metal sulfide‐based hydrogen evolution electrocatalysts still lag in catalytic activity due to the zero‐deviated free energy of *H adsorption. Plasmonic metals bridge the gap between light utilization and plasmon‐mediated redox reactions for substantially enhanced electrocatalytic activity. In this work, a strategic broadband light utilization heterostructure, composed of two distinct Ag nanostructures (discontinuous Ag nanorods and monodispersed nanoparticles), is achieved through in situ sulfurization and metal leaching. The heterostructure benefits the electrocatalytic hydrogen evolution reactivity thanks to the localized surface plasmon resonance induced hot electrons injection and inter‐gap electric fields revealed by the finite‐difference time‐domain simulation. Experimentally, the prudent heterostructured catalyst exhibits a significantly improved overpotential (at 10 mA cm⁻²) from 151 to 95 mV along with a Tafel slope from 74 to 45 mV dec⁻¹ toward hydrogen evolution. Significantly, this instructional study sheds light on the design of hybrid photo‐assisted electrocatalysts with cooperative effect of solar energy toward sustainable electrocatalysis.