Au/TiO2 nanocomposites for efficient hydrogen production

Abstract

Nanocomposites of gold and anatase-titania (Au/TiO2) were prepared via hydrothermal synthesis method. Visible-light photocatalytic water reduction by Au/TiO2 nanocomposites was conducted in the presence of L-ascorbic acid. The characterization of the photocatalysts was by powder X-ray diffraction, transmission electron microscopy, secondary electron microscopy, and UV-Vis photospectrometer. Photocatalytic reactions were carried out with a Xenon lamp with an ultraviolet (UV) cut-off (λ > 420nm) and a Quartz bottle, this alienates the TiO2 UV photocatalytic activity. As such the results recorded indicate the presence of plasmonic-induced photocatalytic activity. Metal to semiconductor unique surface plasmon resonance (SPR) mechanisms were exhibited by the 40nm-2.2wt% Au/TiO2. In addition, the 40nm gold particles portrayed stable absorption bands across various gold concentrations (0.25wt%, 1.5wt% and 2.2wt%). Among the samples synthesized it was the 40nm-2.2wt% Au/TiO2 photocatalyst that produced the highest yield of 3.44mmol/g after 26hours of visible-light irradiation.