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Journal of the Electrochemical Society, Vol.159, No.6, B654-B660, 2012
Oxygen Reduction Reaction on Active and Stable Nanoscale TiSi2 Supported Electrocatalysts
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.