Enhanced hydrogen production activity over BiOX-TiO2 under solar irradiation: Improved charge transfer through bismuth oxide clusters

A series of titania nanoparticles and nanotubes deposited with various quantities of bismuth (Bi) were prepared via sol-gel and hydrothermal methods, respectively. They were then characterized using X-ray diffraction spectroscopy (XRD), X-ray photo electron spectroscopy (XPS), UV-Vis diffused reflectance spectra (DRS), photoluminescence spectra (PLS), transmission electron microscopy (TEM), energy dispersive analysis of X-rays (EDAX), and BET surface analysis. These catalysts were employed for the photocatalytic production of hydrogen from a mixture of pure water and glycerol under solar light irradiation. The presence of the Bi(3 + x)+ species was found to play a vital role in enhancing activity while minimizing electron hole recombination (relative to bare TiO2). The nanotubes exhibited better activity than the nanoparticles of Bi-deposited TiO2, showing the significance of the morphology; however, photocatalytic activity is predominantly dependent on the deposition of bismuth. The activity increased by approximately an order of magnitude at the optimum concentration of Bi deposited over TiO2 (2 wt%). The presence of the Bi(3 + x)+ species played a vital role in minimizing electron hole recombination, resulting in higher activity compared to bare TiO2. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.