Stable and active CuxO/TiO2 nanostructured catalyst for proficient hydrogen production under solar light irradiation

The nanostructured TiO2 materials impregnated with Cu were prepared via a simple and eco-friendly preparation route. The materials are comprised of nano -tubes, -rods and -particles whose surfaces are modified by a fine dispersion of CuxO clusters (Cu degrees and Cu2O) as evidenced by TEM and XPS analysis. Structural and optical characterization ascertained the biphasic (anatase-rutile) crystal structure of TiO2 nano-objects. The presence of CuxO at the surface extends the absorption from the UV to the visible light range. In contrast to the pristine and calcined TiO2 nanotubes (TNT), the CuxO/TiO2 nanostructures (Cu1.5TNT) exhibit a prolonged life-time of photogenerated charge carriers and decreased surface area as confirmed by the photoluminescence spectra and surface area analysis, respectively. The prepared photocatalysts were tested for hydrogen (H-2) production activity using water, mono and di-hydroxylic alcohols solutions under solar light irradiation. Surprisingly, Cu-modified TiO2 nanostructures (Cu1.5TNT) have shown an unusually high rate of H-2 production of about 114.9 +/- 2 mmol h(-1) g(cat)(-1) under a set of optimized experimental conditions. Among all of the studied photocatalysts, the Cu1.5TNT catalyst exhibits enhancements of 33 and 18 fold in the H-2 production rate as compared to the commercial TiO2 nanoparticles (TNP) and calcined TNT, respectively. We report here on the highest known rate of H-2 production using the nanostructured Cu-doped TiO2 photocatalyst (Cu1.5TNT) under solar light irradiation. This unprecedented H-2 production is attributed to synergistic effects of nanocrystalline structures, morphology and copper oxide species (Cu degrees and Cu2O) present in the photocatalyst. (C) 2015 Elsevier B.V. All rights reserved.