Principle of proximity: Plasmonic hot electrons motivate donator-adjacent semiconductor defects with enhanced electrocatalytic hydrogen evolution

Abstract

Defects in layered semiconductors cause large variation of electric and catalysis properties, and exploiting defect-involved reaction can deeply excavate unearthed characteristics with significant performances. Mo-terminated defects of MoS2 spontaneously guide the oriented growths of ultrasmall Au nanocrystals on specific sites of liquid-exfoliated (LE) nanosheets, which are experimentally and theoretically performed with programmable heterostructures. The conjugated construction of Au plasmonics and MoS2 semiconductors is manipulated with the aim of the optimal synergistic activity. Additionally, with photonic irradiation, hot electrons excited from attached plasmonic nanostructures are injected into MoS2 semiconductors, which remarkably increases the carrier density of catalyst to match the energy level of hydrogen evolution reaction (HER). Obeying the principle of proximity, localized MoS2 defect-adjacent Au plasmonics exhibit a more valid pathway, transferring hot electrons from donators to receptors of catalytic sites, in comparison to planar Au decoration. Meanwhile, Au nanostructures located at basal planes are essential for accelerated electron transport rates between catalysts and electrodes, and high stabilities in plasmonic-motivated electrocatalytic performances are guaranteed. The dual function of location-discriminated Au nanostructures accounts for superior electrocatalytic HER performances with photonic excitation, which imparts high inspiration in expanded heterostructures and integrated plasmonic techniques for catalysis and devices.