The continuous improvement of the anode materials constitutes a major challenge for the future commercial use of polymer electrolyte membranes (PEM) electrolyzers for hydrogen production. In accordance to this direction, iridium/titanium films deposited directly on carbon substrates via magnetron sputtering are operated as electrodes for the oxygen evolution reaction interfaced with Nafion 115 electrolyte in a laboratory single cell PEM hydrogen generator. The anode with 0.2 mg cm(-2) It catalyst loading was electrochemically activated by cycling its potential Value between 0 and 1.2 V (vs. RHE). The water electrolysis cell was operated at 90 degrees C with current density 1A cm(-2) at 1.51 V without the ohmic contribution. The corresponding current density per mgr of Ir catalyst is 5 A mg(-1). The achieved high efficiency is combined with sufficient electrode stability since the oxidation of the carbon substrate during the anodic polarization is almost negligible. (c) 2008 Elsevier B.V. All rights reserved.