Hot Hole Photoelectrochemistry on Au@SiO₂@Au Nanoparticles

Abstract

There is currently\na worldwide need to develop efficient photocatalytic\nmaterials that can reduce the high-energy cost of common industrial\nchemical processes. One possible solution focuses on metallic nanoparticles\n(NPs) that can act as efficient absorbers of light due to their surface\nplasmon resonance. Recent work indicates that small NPs, when photoexcited,\nmay allow for efficient electron or hole transfer necessary for photocatalysis.\nHere we investigate the mechanisms behind hot hole carrier dynamics\nby studying the photodriven oxidation of citrate ions on Au@SiO₂@Au core–shell NPs. We find that charge transfer to\nadsorbed molecules is most efficient at higher photon energies but\nstill present with lower plasmon energy. On the basis of these experimental\nresults, we develop a simple theoretical model for the probability\nof hot carrier–adsorbate interactions across the NP surface.\nThese results provide a foundation for understanding charge transfer\nin plasmonic photocatalytic materials, which could allow for further\ndesign and optimization of photocatalytic processes.