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Nano Research

Article Title

Pt x Cu y nanocrystals with hexa-pod morphology and their electrocatalytic performances towards oxygen reduction reaction

Keywords

oxygen reduction reaction, bimetallic alloy, morphology control, fuel cell electro-catalysis, high-index

Abstract

Bimetallic PtxCuy nanocrystals (NCs) with well-defined hexa-pod morphology were synthesized via a wet chemistry approach. The as-synthesized convex NCs with dimensions of around 20 nm show exposed low-index (111) facets on the seeds and various high-index facets on the pods. The growth mechanism involved preferred growth along the crystallographic direction on cuboctahedral seeds. The synthetic protocol could be applied to the synthesis of PtxCuy NCs with various Cu/Pt ratios. The electro-catalytic activity of the hexa-pod PtxCuy NCs supported on carbon black towards the oxygen reduction reaction (ORR) was studied. The hexa-pod PtCu2/C catalysts exhibit the highest specific activity (3.7 mA/cm2 Pt) and mass activity (2.4 A/mgPt) reported to date for PtxCuy. Comparison with other morphological forms of PtxCuy indicated that the enhanced activity originated from morphological factors. The existence of high-index facets as well as abundant edges and steps on the pods could reasonably explain the enhanced catalytic activity. The hexa-pod PtxCuy/C catalysts also show high morphological stability and activity after accelerated durability tests. The as-synthesized hexa-pod PtxCuy NCs have high potential as cathode electro-catalysts for proton exchange membrane fuel cells.

Graphical Abstract

Publisher

Tsinghua University Press

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