Localized Surface Plasmon Resonance-Induced Interfacial Dynamic Charge Circulation in Plasmonic Ohmic Heterojunctions for Optimizing Hydrogen Evolution Kinetics

Abstract

It remains a formidable challenge to precisely regulate interfacial charge transfer kinetics via architecting high-efficiency heterointerfaces, thereby achieving optimized hydrogen evolution reaction (HER) activity. Here, we report a strategy based on work function-mediated heterojunction engineering, through which the V₂C MXene/ZnS plasmon ohmic heterojunction (ZC-10) was precisely designed and synthesized, achieving the synergistic optimization of hydrogen evolution kinetics from the dual dimensions of carrier transport and electronic structure. Combined results from in situ XPS, KPFM, EPR, and femtosecond transient absorption (fs-TA) spectroscopy, alongside density functional theory (DFT) calculations, demonstrate that the introduction of V₂C MXenes not only significantly enhances the light-harvesting capability of the ZnS but also simultaneously activates both the enriched excited-state electrons and intrinsic free electrons within V₂C MXenes via the localized surface plasmon resonance (LSPR) effect. These electrons are co-converted into high-energy excited electrons. These energetic electrons undergo reverse injection into the conduction band of ZnS for stabilization, which establishes a dynamic charge circulation mechanism at the heterojunction interface, thereby prolonging the carrier lifetime of the ZC-10 plasmon ohmic heterojunction. Meanwhile, the d–p orbital hybridization effect in the ZC-10 heterojunction activates its d¹⁰ electronic configuration, thereby simultaneously optimizing the d–p double orbital center. Such synergistic modulation of the electronic structure effectively balances the kinetics of the hydrogen adsorption/desorption (H_ADS/H_DES) processes, substantially lowering the Gibbs free energy of H^* adsorption (ΔG_H). This work provides an example for designing high-performance MXene-based plasmon photocatalysts.