Gold and gold-palladium alloy nanoparticles on heterostructured TiO2 nanobelts as plasmonic photocatalysts for benzyl alcohol oxidationElectronic supplementary information (ESI) available. See DOI: 10.1039/c4nr05905k

Plasmonic photocatalysts composed of Au and bimetallic Au-Pd alloy nanoparticles (NPs) on one-dimensional TiO 2 nanobelts (TiO 2 -NBs) were used for the aerobic oxidation of benzyl alcohol under visible light irradiation. Remarkable light-promoted activity was observed for the as-synthesized M/TiO 2 -NB (M = Au, Au-Pd) nanostructures based on the TiO 2 (B)/anatase heterostructured nanobelt. The difference in band structure and the well matched interface between the TiO 2 (B) and anatase phases, coupled with the one-dimensional nanostructure, enable an enhanced charge transfer within the heterostructured nanobelt. This inter-phase charge transfer greatly facilitates the flow of hot electrons from the metal NPs to TiO 2 and promotes benzyl alcohol oxidation. This efficient electron transfer was identified by the much higher photocurrent response measured for the Au/TiO 2 -NB nanostructure with the TiO 2 (B)/anatase heterojunction than those with either of the single phases under visible light irradiation. Alloying Au with Pd in Au-Pd/TiO 2 -NB results in a significant improvement in the visible light-promoted activity compared to the monometallic Au/TiO 2 -NB sample. It is supposed that the plasmon-mediated charge distribution within the alloy NPs is mainly responsible for the enhanced photocatalytic activity of the bimetallic nanostructures. The superior visible light-promoted activities of Au and Au-Pd alloy nanoparticles on heterostructured TiO 2 nanobelts for the aerobic oxidation of benzyl alcohol is driven by the plasmon-mediated electron transfer process.