The effect of impregnation of nano-sized Y2O3-ZrO2 (YSZ) particles into nickel anodes on the performance and electrode behaviour for the hydrogen oxidation reaction is investigated. Incorporation of nano-YSZ particles significantly reduces the electrode polarization resistance and overpotentials for the hydrogen oxidation reaction. Furthermore, the electrode behaviour for the hydrogen oxidation reaction on the nano-YSZ impregnated nickel anode is clearly differentiated at low and high frequencies. Impregnation of nano-YSZ particles primarily decreases the electrode polarization resistance at high frequencies, which indicates that the main role of the impregnated YSZ is to extend the three-phase boundary areas into the bulk of the nickel anode. The results suggest that the electrode process at low frequencies may be dominated by the dissociative adsorption of hydrogen. (c) 2005 Elsevier B.V. All rights reserved.