The aim of the work is to show that hydrogen can be cathodically inserted into zinc oxide. This process corresponds to an actual doping of the material. The doped material shows a high potential stability, with moderate reversibility, when measured against a platinum-hydrogen electrode, and using a proton conductor as electrolyte. Evidence of hydrogen chemisorption onto zinc oxide surface is also given. (c) 2006 Elsevier Ltd. All rights reserved.