Al@TiO₂ Core-Shell Nanoparticles for Plasmonic Photocatalysis

Plasmon-induced photocatalysis is a topic of rapidly increasing interest, due to its potential for substantially lowering reaction barriers and temperatures and for increasing the selectivity of chemical reactions. Of particular interest for plasmonic photocatalysis are antenna-reactor nanoparticles and nanostructures, which combine the strong light-coupling of plasmonic nanostructures with reactors that enhance chemical specificity. Here, we introduce Al@TiO₂ core-shell nanoparticles, combining earth-abundant Al nanocrystalline cores with TiO₂ layers of tunable thickness. We show that these nanoparticles are active photocatalysts for the hot electron-mediated H₂ dissociation reaction as well as for hot hole-mediated methanol dehydration. The wavelength dependence of the reaction rates suggests that the photocatalytic mechanism is plasmonic hot carrier generation with subsequent transfer of the hot carriers into the TiO₂ layer. The Al@TiO₂ antenna-reactor provides an earth-abundant solution for the future design of visible-light-driven plasmonic photocatalysts.