Photocatalytic water decomposition for hydrogen production over silicotungstic acid-silica photocatalyst

A novel photocatalytic water decomposition to produce hydrogen was investigated over silicotungstic acid (SWA)-silica photocatalyst under UV irradiation. SWA-silica photocatalysts were prepared by impregnation of SWA on silica support as a function of solvent and mixing time of SWA and silica. The catalysts were characterized by BET surface area, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microspectroscopy equipped with energy-dispersive X-ray spectroscopy and UV-vis diffuse reflectance spectroscopy. The charge transfer resistances of photocatalysts were analyzed by AC impedance measurement. The superior photocatalytic performance to produce hydrogen over SWA-silica is ascribed to the formation of secondary structure of SWA over silica support. Such a secondary structure results in the formation of bonding between SWA and support that is believed to be a dominant root for hydrogen evolution. The presence of SWA along with silica gives rise to the decrease in the charge transfer resistance, which is consistent with the superior performance of SWA-silica system.