Long-distance transfer of plasmonic hot electrons across the Au–Pt porous interface for the hydrogen evolution reaction

Abstract

Plasmonic photocatalysis on bimetallic heterostructures via plasmonic hot electrons (e_ph⁻) has received significant attention owing to their ability to harvest solar energy and high catalytic activities, whereas the mechanism of the e_ph⁻ transfer at the metal–metal interfaces is still not completely understood owing to the chemical interface damping. Here, the e_ph⁻ transfer from Au nanospheres (Au NSs) to the Pt interface is directly imaged by plasmon resonance light scattering (PRLS) microscopy. Under the plasmonic resonance illumination (PRI), e_ph⁻ generated from Au NSs reduced PtCl₆²⁻ to Pt(0) atoms, which are deposited on the surface of Au NSs to form a porous Au@Pt porous core–shell nanostructure (Au@Pt NS), and thus e_ph⁻ could persistently transfer across the Au–Pt interface longer than 20 nm to further improve hydrogen evolution reaction (HER), which is further confirmed by ultrafast transient absorption spectra and transient photocurrent responses. This study promotes the understanding of the distance of e_ph⁻ transfer at metal–metal interfaces to improve the separation efficiency of hot carriers in plasmonic-enhanced applications.