Hydrogen photoproduction from ethanol-water mixtures over Au-Cu alloy nanoparticles supported on TiO2

Abstract

Au/TiO2, Au0.75Cu0.25/TiO2, Au0.5Cu0.5/TiO2 and Au0.25Cu0.75/TiO2 photocatalysts prepared from pre-formed Au and Au-Cu alloy nanoparticles of controlled composition and size were loaded over ceramic honeycombs (2 mg cm(-2)) and tested in an optical fiber photoreactor illuminated with UV LEDs (2.6 mW cm(-2)) to continuously produce hydrogen from water and ethanol mixtures in gas phase at W/F = 4 g min L-1 and 298 K (where W is the weight of the catalyst and F is the flow rate). The photocatalytic honeycombs were characterized by high resolution transmission electron microscopy, high-angle annular dark-field imaging, energy dispersive X-ray, X-ray photoelectron spectroscopy, and UV-Vis spectroscopy. The yield of hydrogen generation was Au0.75Cu0.25/TiO2 > Au0.5Cu0.5/TiO2 similar to Au/TiO2 > Au0.25Cu0.75/TiO2 >> bare TiO2, thus demonstrating that the addition of small quantities of copper to conventional TiO2-supported gold photocatalysts promotes the photocatalyic activity, likely by providing effective charge transfer between Au and Cu in the alloy nanoparticles.