Using hot-electrons and hot-holes for simultaneous cocatalyst deposition on plasmonic nanostructures.

Hot-electrons generated in metal nanoparticles can drive chemical reactions and selectively deposit cocatalyst materials on the plasmonic hot-spots, the areas where the decay of plasmons takes place and the hot-electrons are created. While hot-electrons have been extensively used for nanomaterial formation, the utilization of hot-holes for simultaneous cocatalyst deposition has not yet been explored. Herein, we demonstrate that hot-holes can drive an oxidation reaction for the deposition of manganese oxide (MnOx) cocatalyst on different plasmonic gold (Au) nano-structures on a thin titanium dioxide (TiO2) layer, excited at their surface plasmon resonance. An 80% correlation between the hot-hole deposition sites and the simulated plasmonic hot-spot location is showed, when considering the typical hot-hole diffusion length. Simultaneous deposition of more than one cocatalyst is also achieved on one of the investigated plasmonic systems (Au plasmonic nano-islands) through the hot-hole oxidation of a manganese salt and the hot-electron reduction of a platinum (Pt) precursor in the same solution. These results add more flexibility to the use of hot-carriers and open up the way for the design of complex photocatalytic nanostructures.