Received October 18, 2007

Abstract:

We report the combinatorial and high-throughput optimization of improved ternary Pt alloy electrocatalysts for the oxidation of methanol for use in direct methanol fuel cell (DMFC) anodes. Following up on the discovery of a ternary Pt₂₀Co₆₀Ru₂₀ catalyst¹ with significantly improved electrocatalytic activity for methanol oxidation over standard Pt−Ru catalysts, we optimize the electrocatalytic activity of this composition using a closely sampled Pt−Co−Ru “optimization library”. We also screen for compositional and structural stability using high-throughput methods. Composition−activity maps confirmed improved activity in compositional neighborhood of the Pt₂₀Co₆₀Ru₂₀ catalyst. Activity trends of Pt−Ru binary alloys were in excellent agreement with fundamental surface electrochemical studies. Structural and compositional catalyst stability was probed using X-ray diffraction (XRD) and energy dispersive X-ray analysis (EDX). Combination of the stability−composition and activity−composition maps resulted in “consensus maps” pointing to a new optimized ternary alloy electrocatalyst for methanol electrooxidation with an overall composition of Pt₁₈Co₆₂Ru₂₀.

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