Al@TiO₂ Core–Shell Nanoparticles\nfor Plasmonic Photocatalysis

Abstract

Plasmon-induced photocatalysis is\na topic of rapidly increasing\ninterest, due to its potential for substantially lowering reaction\nbarriers and temperatures and for increasing the selectivity of chemical\nreactions. Of particular interest for plasmonic photocatalysis are\nantenna–reactor nanoparticles and nanostructures, which combine\nthe strong light-coupling of plasmonic nanostructures with reactors\nthat enhance chemical specificity. Here, we introduce Al@TiO₂ core–shell nanoparticles, combining earth-abundant Al nanocrystalline\ncores with TiO₂ layers of tunable thickness. We show that\nthese nanoparticles are active photocatalysts for the hot electron-mediated\nH₂ dissociation reaction as well as for hot hole-mediated\nmethanol dehydration. The wavelength dependence of the reaction rates\nsuggests that the photocatalytic mechanism is plasmonic hot carrier\ngeneration with subsequent transfer of the hot carriers into the TiO₂ layer. The Al@TiO₂ antenna–reactor provides\nan earth-abundant solution for the future design of visible-light-driven\nplasmonic photocatalysts.