Gold(Core)-Lead(Shell) Nanoparticle-Loaded Titanium(IV) Oxide Prepared by Underpotential Photodeposition: Plasmonic Water Oxidation.

Abstract

Underpotential photodeposition of Pb yields an ultrathin shell layer on the Au(111) surface of Au nanoparticle(NP)-loaded TiO2 (Au/TiO2 ) with heteroepitaxial nanojunctions. The localized surface plasmon resonance of Au/TiO2 undergoes no damping with the Pb-shell formation, and the Pb shell offers resistance to aerobic oxidation. Mesoporous films comprising the Au(core)-Pb(shell) NP-loaded TiO2 and unmodified Au/TiO2 were formed on fluorine-doped tin oxide (FTO) electrode. Using them as the photoanode, photoelectrochemical cells were fabricated, and the photocurrent was measured under illumination of simulated sunlight. The photocurrent for water splitting is dramatically enhanced by the Pb-shell formation. The photoelectrochemical measurements of the hot-electron lifetime and density functional theory calculations for model clusters indicate that the Pb-shell effect originates from the charge separation enhancement.