Tungsten(VI) Oxide Flake-Wall Film Electrodes for Photoelectrochemical Oxygen Evolution from Water

A vertically arrayed flake film, "flake-wall film", of monoclinic tungsten(VI) oxide (WO3) was prepared on a transparent conductive glass. The WO3 flake-wall film exhibited superior performance for photoelectrochemical water oxidation under visible-light irradiation compared to that of a film consisting of horizontally laminated WO3 flakes. The small difference between photocurrent densities under front-side irradiation and back-side irradiation indicates the excellent electron transport property of the flake-wall film.