Novel Metal@Titania Yolk-Shell Photocatalysts For Hydrogen Production: The Role of the Metal Revisited

Evidence from photophysical and photocatalytic measurements using Au@TiO₂ and Void@TiO₂ core-shell samples is provided to argue against the conventional explanation for photocatalysis with metal/semiconductor catalysts and to support an alternative model where hydrogen reduction occurs on the semiconductor surface and where the metal promotes recombination of H· to H₂.