Hydrogen evolution by water splitting using novel composite zeolite-based photocatalyst

Novel zeolite-based material showing photocatalytic properties in the visible light have been synthesized by incorporating TiO₂, heteropolyacid (HPA) and transition metal, namely cobalt. This material shows high efficiency for water splitting under visible light irradiation. Hydrogen generation to the tune of 2171 μmol/h/g of TiO₂ has been achieved for the composite photocatalyst synthesized as compared to H₂ evolution rate to the tune of 131.6 μmol/h/g of TiO₂ for Degussa P25. This suggests that the TiO₂ which gets effectively dispersed and stabilized on the surface of zeolite works synergistically with cobalt and heteropolyacid to make the material active in visible light for evolution of hydrogen from water. TiO₂ is the photocatalyst, HPA functions as the dye sensitiser as well as redox system; zeolite functions as support matrix and as electron acceptor in synergy with cobalt. The probable mechanism for improved hydrogen evolution rate using such composite photocatalyst has been discussed.