Photocatalytic Reforming of Biomass Derived Crude Glycerol in Water: A Sustainable Approach for Improved Hydrogen Generation Using Ni(OH)(2) Decorated TiO2 Nanotubes under Solar Light Irradiation

Crude glycerol (10% w/w) is produced as a substantial byproduct during the industrial production of biodiesel via transesterification processes. Catalytic hydrogen (H-2) generation by utilizing crude glycerol and solar light is considered as a promising avenue. The present work illustrates enhanced rates of H-2 generation and cocatalyst behavior of Ni(OH)(2) decorated on TiO2 nanotubes dispersed in aqueous crude glycerol solution (industrial byproduct) under solar light irradiation. The catalyst characterization reveals that the TiO2 nanotubes (TNT) are of anatase phase with length ranges from 100 to 300 nm and diameters from 4.9 to 9.8 nm. The Ni(OH)(2) quantum dots deposited on TNT have an average particle size of 8.4 nm. The presence of Ni(OH)(2) on TNT and oxidation states of Ti4+ and Ni2+ cations are confirmed by XPS analysis. The optimal loading of Ni (2.0 wt %) leads to a high rate of photocatalytic H-2 generation of 4719 mu mol h(-1) g(cat)(-1) and it is similar to 12-fold higher than pristine TNT. The solar light energy conversion efficiency of the optimized catalyst and cost benefit analysis by using crude glycerol are also evaluated. The high electronegativity of Ni(OH)(2) quantum dots present on the surface of TNT may facilitate effective shuttling of photoexcitons, thereby largely preventing electron-hole recombination in TiO2 during photocatalysis.