A Three-Component Plasmonic Photocatalyst Consisting of Gold Nanoparticle and TiO2-SnO2 Nanohybrid with Heteroepitaxial Junction: Hydrogen Peroxide Synthesis

摘要

SnO2 nanorods were hydrothermally grown on rutile TiO2 seed crystals (SnO2-NR#TiO2), where symbol # denotes the heteroepitaxial junction between SnO2 and TiO2. Furthermore, Au nanoparticles (NPs) were loaded on the surfaces of TiO2 and SnO2 of SnO2-NR#TiO2 by the deposition precipitation method (Au/[SnO2-NR#TiO2]). Au/[SnO2-NR#TiO2] possesses broad and strong absorption due to the localized surface plasmon resonance (LSPR) of Au NPs around 550 nm, while both TiO2 and SnO2 are almost transparent to visible light. On excitation of the LSPR (lambda(ex) > 430 nm), Au/[SnO2-NR#TiO2] exhibits much higher photocatalytic activity for two-electron oxygen reduction reaction than two-component systems of Au/TiO2 and Au/SnO2 and their physical mixture. The striking photocatalytic activity of the three-component system stems from the efficient charge separation due to the LSPR-driven vectorial interfacial electron transfer in the direction of Au (on TiO2 -> TiO2 -> SnO2 -> Au (on SnO2). Consequently, Au NPs on TiO2 and SnO2 work as the oxidation and reduction sites, respectively, and thus, the excellent electrocatalytic activity of Au NP for two-electron oxygen reduction reaction and low catalytic activity of SnO2 for H2O2 decomposition would also contribute to the high photocatalytic activity.