Developing Metal–Semimetallic Transition Metal Dichalcogenide Interfaces in Plasmonic Au/NbS ₂ Heterostructures for Enhanced Charge Transfer and Photoelectrochemical Hydrogen Evolution Reaction

ABSTRACT The development of cost‐effective and highly‐efficient photoelectrodes (PE) is critical for advancing solar driven photoelectrochemical (PEC) hydrogen (H ₂ ) production technologies. For enhancing PEC performance, it appears promising to combine plasmonic nanoparticles with active catalysts. Here we report a facile and powerful PE comprised of Au nanoparticles (NP) decorated on NbS ₂ nanoflakes (NF), directly grown on the carbon fiber paper. In this heterostructure, Au NP acts as plasmonic antennas that intensify local electromagnetic fields strengthening light matter interactions, NbS ₂ NF functions as a highly conductive semimetal scaffold offering abundant active HER sites, and the junction of Au NP/NbS ₂ NF enables efficient charge separation and fast electron transfer from NbS ₂ to Au, thereby synergistically accelerating HER kinetics under illumination. Consequently, this Au NP/NbS ₂ NF heterostructure, for the first time, demonstrates remarkable PEC performance under illumination, such as a 6‐fold increase in the exchange current density, a 1.75‐fold reduction in overpotential, and a 2.45‐fold yield in the H ₂ production, respectively. Based on the heterostructure of Au NP/NbS ₂ NF, this work establishes a strategy of constructing a cost‐effective and highly‐efficient PE and providing valuable insights into the rational design of next generation PE for the sustainable hydrogen production.