A hydrogen peroxide-treated carbon support was used to prepare electrocatalysts for low temperature fuel cells. The electrochemical stability of the Pt/C catalysts was evaluated by potential scan tests. The results show that the oxidative treatment introduces oxygen-bearing functional groups onto the support surface. These functional groups connect with metal nanoparticles via 0 atoms so as to alleviate the agglomeration of supported nanocatalysts. During the test, the mean particle size of catalysts increased from 2.5 nm and 2.6 nm to 5.3 nm and 4.8 nm for untreated and treated carbon support, respectively. Electrochemical surface area measurements also show that the oxidative treatment of carbon support enhanced the electrochemical stability of Pt/C catalysts. It is suggested that the chemical interaction between the metal particle and the oxygen-bearing functional group plays an important role in immobilizing catalyst nanoparticles. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.