Tuning the Reactivity of Al@TiO₂ Antenna-Reactor Plasmonic Photocatalysts by Controlling Oxygen Vacancies

Oxygen vacancies on a metal oxide surface enhance its catalytic activity. Here we investigate the controlled introduction of oxygen vacancies on core-shell Al@TiO₂ antenna-reactor nanoparticle photocatalysts. Thermal annealing in an H₂-reducing atmosphere creates more oxygen vacancies in the surface TiO₂ layer of Al@TiO₂ nanoparticles compared to the same process under inert (He) or oxidative (O₂) ambients. The photocatalytic reactivity enhancement was evaluated by investigating two reactions: hole-mediated methanol decomposition and electron-mediated hydrogen dissociation. The ability to modify plasmonic nanoparticle photocatalyst reactivity in this simple and controllable manner demonstrates the potential of this approach to tailor and enhance the performance of plasmonic antenna-reactor photocatalysts.