Simultaneous electrochemical activity and kinetic stability of the electrode materials are of paramount importance to the commercialization of proton exchange membrane fuel cells. In this paper, we report a new material, titanium disilicide (TiSi2), to support nano Pt electrocatalysts that were synthesized via a colloidal approach. Accelerated durability test (ADT) shows that the oxygen reduction electrode made of Pt/TiSi2 exhibits substantial improvement over commercial Pt/C electrode in terms of the kinetic stability. After 2000 ADT cycles, the electrochemical surface area of Pt/TiSi2 decreases to similar to 73% of the initial magnitude, compared to 36% of Pt/C electrodes. The ADT results are consistent with the analysis of Pt particle size by transmission electron microscopy, which shows aggregation of Pt nanoparticles in Pt/C and marginal growth of Pt with TiSi2 as the support. Oxygen reduction reactions on Pt/TiSi2 take place via a four-electron electrochemical process. A similar Tafel behavior is observed in Pt/TiSi2 and Pt/C electrodes, suggesting the presence of similar oxygen reduction mechanisms in both electrodes. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.042206jes] All rights reserved.