Mechanisms of activity loss in PtCo alloy systems

Ball, Sarah C, Hudson, Sarah L, Hei Leung, Joe, Russell, Andrea E, Thompsett, David and Theobald, Brian R (2007) Mechanisms of activity loss in PtCo alloy systems. ECS Transactions, 11 (1), 1247-1257. (doi:10.1149/1.2781038).

Abstract

The mechanism of activity loss in Pt and PtCo alloy systems has been investigated during 0.6 - 1.0 V and 0.6 - 1.2 V vs RHE cycling regimes using an electrochemical cell that allows electrochemical metal area (ECA) loss measurement and electrolyte sampling. Dissolution of platinum and base metal into the electrolyte was quantified using ICP-MS and TEM used to look for changes in catalyst morphology with cycles. ECA loss and base metal removal were found to be potential dependent. PtCo alloys were found to be more stable to ECA loss by Ostwald-ripening and dissolution than Pt. In terms of base metal loss the PtCo alloy was unstable and cycling was found to remove similar amounts of Co by dissolution as chemical acid leaching. Loss of Co from the surface layers of the catalyst was found to remove the enhanced stability and activity benefits of this catalyst making it more platinum like

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Contributors

Author: Andrea E Russell

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