Electrochemical water oxidation by photo-deposited cobalt-based catalyst on a nano-structured TiO_2 electrode

摘要

A cobalt-based catalyst was directly photo-deposited on the surface of a widely used n-type nano-structured semiconductor(TiO 2).Different thicknesses of the TiO 2 films as well as different time of photo-deposition of the Co-based catalyst on TiO 2 films have been optimized.It was found that the electrode with 3 layers of TiO 2 film(in 8 m thickness) and 1 hour photo-deposition of the cobalt-based catalyst by light irradiation from a 500 W Xenon lamp gave the highest current density(～5 mA/cm 2).Using this cobalt-modified TiO 2 film as a working electrode in an electrochemical device,highly efficient water oxidation has been demonstrated in a pH 7.0 aqueous solution with low overpotential.