Platinum-ruthenium (Pt-Ru) on a Nafion(Na+)-bonded carbon layer is fabricated by using galvanostatic pulse electrode position for high utilization of catalysts and cost reduction. The composition of the Pt-Ru electrode, which is controlled by varying the concentration of the Ru precursor, is determined by inductively coupled plasma-atomic emission spectroscopy and by electron probe microanalysis. The particle size of the electrodeposited Pt-Ru catalyst is determined by high-resolution transmission electron microscopy. Other characterizations are carried out by X-ray diffraction, X-ray photoelectron spectroscopy, and CO-stripping voltammetry. Electrodeposited Pt-Ru catalysts give improved performance, not only in single-cell operations but also with respect to CO tolerance compared with electrodes prepared by conventional means. The behaviour is probably due to enhanced utilization of the catalysts. Recovery from CO exposure demonstrates that the electrodeposited catalysts exhibit better resistance to Co. (C) 2008 Elsevier B.V. All rights reserved.