The present invention relates to an electrode comprising an electrically conductive substrate of which at least one portion of the surface is covered with a metal deposit of copper, the surface of said deposit being in an oxidised, sulphurised, selenised and/or tellurised form and the deposit having a specific surface area of more than 1 m2/g; a method for preparing such an electrode; and a method for oxygenising water with dioxygen involving such an electrode.