Photocatalytic splitting of water on NiO/InTaO4 catalysts prepared by an innovative sol-gel method

InTaO4 is a photocatalyst with visible-light response that is used to split water and produce hydrogen. InTaO4 is traditionally prepared by solid-state fusion of In2O3 and Ta2O5 at >= 1100 degrees C. A sol-gel procedure was developed to synthesize InTaO4 from In(NO3)(3) and Ta(OC4H9)(5) precursors. A uniform crystalline InTaO4 phase was easily obtained on calcination at 1100 degrees C because the sol-gel method allows homogeneous liquid-phase mixing. The method yields small InTaO4 particles with a high specific surface area. InTaO4 catalysts with different Ni loading were prepared by incipient wetness impregnation. Ni loading greatly enhanced the initial rate of H-2 production during photocatalytic splitting of water. Ni metal within Ni-NiO core/shell nanoparticles can efficiently transfer photoelectrons on the InTaO4 surface and thus reduce H+ to hydrogen. NiOx/InTaO4 was deactivated due to the formation of Ni(OH)(2). Overall, NiOx/InTaO4 prepared by the sol-gel method had higher activity than catalysts prepared by solid-state fusion. Among all the photocatalysts, 3.0 wt.% NiOx/InTaO4 exhibited the highest photoactivity, with an initial rate of H-2 production of 2.10 mu mol/g h. (C) 2009 Elsevier B.V. All rights reserved.