Hydrogen generation

Chem. Mater. http://doi.org/j5g (2012)

Dye-sensitized solar cells based on wide-bandgap semiconductor oxides have now been shown to reach solar-energy conversion efficiencies of more than 10% and are considered to be a promising low-cost alternative to traditional silicon photovoltaic devices. Orthorhombic Nb₂O₅ nanocrystalline films functionalized with a RuP compound are now proposed by Thomas Meyer and colleagues as photoanodes in dye-sensitized photoelectrosynthesis cells for hydrogen generation. Compared with anatase TiO₂ and with what is generally believed, the conduction band potential for the T-phase orthorhombic Nb₂O₅ film is measured to be only slightly higher and is dominated by shallow band-tail trap states. In an operating dye-sensitized photoelectrosynthesis cell, with an ethylenediaminetetraacetic tetra-anion added as a reductive scavenger, hydrogen, quantum yield and photostability measurements show that Nb₂O₅ is comparable to TiO₂. Overall these results demonstrate that Nb₂O₅ is a promising alternative photoanode material for photoelectrochemical applications.