Anisotropic Growth of TiO2 onto Gold Nanorods for Plasmon-Enhanced Hydrogen Production from Water Reduction

Plasmonic metal/semiconductor heterostructures show promise for visible-light-driven photo catalysis. Gold nanorods (AuNRs) semi-coated with TiO2 are expected to be ideally structured systems for hydrogen evolution. Synthesizing such structures by wet-chemistry methods, however, has proved challenging. Here we report the bottom-up synthesis of AuNR/TiO2 nanodumbbells (NDs) with spatially separated Au/TiO2 regions, whose structures are governed by the NRs' diameter, and the higher curvature and lower density of C-n TAB surfactant at the NRs' tips than on their lateral surfaces, as well as the morphology's dependence on concentration, and alkyl chain length of C-n TAB. The NDs show plasmon-enhanced H-2 evolution under visible and near-infrared light.