Size-Dependence of the Activity of Gold Nanoparticle-Loaded Titanium(IV) Oxide Plasmonic Photocatalyst for Water Oxidation

Mesoporous TiO2 nanocrystalline film was formed on fluorine-doped tin oxide electrode (TiO2/FTO) and gold nanoparticles (NPs) of different sizes were loaded onto the surface with the loading amount kept constant (Au/TiO2/FTO). Visible-light irradiation (lambda > 430 nm) of the Au/TiO2/FTO photoanode in a photoelectrochemical cell with the structure of photoanode vertical bar 0.1 M NaClO4 aqueous solution vertical bar Ag/AgCl (reference electrode)vertical bar glassy carbon (cathode) leads to the oxidation of water to oxygen (O-2). We show that the visible-light activity of the Au/TiO2/FTO anode increases with a decrease in Au particle size (d) at 2.9 <= d <= 11.9 nm due to the enhancement of the charge separation and increasing photoelectrocatalytic activity.