The nano-structured nickel-21 at.% tungsten alloys were electrodeposited onto the copper substrates from unstirred sulfate-citratechloride-bromide-sodium tungstate electrolyte at 60degreesC. The maximum particle sizes of the deposits, as estimated from the atomic force microscopy (AFM), and scanning electron microscopy (SEM), respectively were 125, 75, and 100 rim. The Tafel plot for oxygen reduction reaction in oxygenated unstirred 1% sodium hydroxide solution showed a Tafel slope of 130 mV/decade. There were minor variations in the limiting current density with a change in the particle size. (C) 2004 Elsevier Ltd. All rights reserved.