Photocatalysis by Au nanoparticles: Reforming of methanol

Abstract

Au/TiO2 catalysts were prepared by incipient wetness impregnation and tested for the room temperature photocatalytic reforming of methanol in aqueous solution to produce hydrogen. These catalysts proved to be active for this reaction, with the dependence on loading of gold showing a double maximum in yield at 0.2 and 2 weight % with a low rate below 0.01% and above 10%. A model is proposed for the reaction, involving band gap excitation of titania electrons to produce O- species which are then used to oxidise the methanol via adsorbed methoxy, which is formed by dehydrogenation on the metal component. The reaction is truly bi-functional and only takes place at the interface between the metal and the support.