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Research Article

Shaped Pt-Ni nanocrystals with an ultrathin Pt-enriched shell derived from one-pot hydrothermal synthesis as active electrocatalysts for oxygen reduction

Jun Gu1,§, Guangxu Lan1,§, Yingying Jiang2,§, Yanshuang Xu1, Wei Zhu1, Chuanhong Jin2, Yawen Zhang1( )
Beijing National Laboratory for Molecular ScienceState Key Laboratory of Rare Earth Materials Chemistry and ApplicationsPKU-HKU Joint Laboratory in Rare Earth Materials and Bioinorganic ChemistryCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871China
State Key Laboratory of Silicon MaterialsKey Laboratory of Advanced Materials and Applications for Batteries of Zhejiang Province and School of Materials Science and EngineeringZhejiang UniversityHangzhou310027China

§ These authors contributed equally to this work.

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Graphical Abstract

Abstract

Alloy nanocrystals (NCs) of Pt with 3d transition metals, especially Ni, are excellent catalysts for the oxygen reduction reaction (ORR). In this work, we, for the first time, demonstrated the water phase colloidal synthesis of Pt-M (M = Ni, Co and Fe) alloy NCs with tunable composition and morphology through a facile hydrothermal method. Pt-Ni alloy NCs synthesized with this method presented better ORR activity than commercial Pt/C catalysts. The X-ray energy dispersive spectra (EDS) mapping technique revealed that Pt-enriched shells existed on the as-synthesized Pt-Ni alloy NCs. About two atom thick layered Pt-enriched shells formed on Pt50Ni50 NCs and the thickness of the Pt-enriched shells increased as the Ni content increased. Furthermore, X-ray photoelectron spectroscopy analysis revealed that the oxidation level of the surface Pt atoms on the Pt-Ni alloy NCs decreased compared with monometallic Pt NCs, implying a decrease in the oxophilicity of the surface Pt atoms. Pt-Ni alloy NCs with lower oxophilicity of the surface Pt atoms give higher ORR activity. The most active alloy sample showed 13 times higher specific activity and six times higher mass activity at 0.9 V vs. a reversible hydrogen electrode when compared with commercial Pt/C. Pt-Ni alloy NCs also showed better durability than commercial Pt/C in long term ORR tests.

Keywords

Pt-NiPt-Ni alloy nanocrystalsbimetallic catalystsoxygen reduction reactiondealloyingaqueous-phase synthesis

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Nano Research
Volume 8 Issue 5,
May 2015
Pages 1480-1496
DOI: 10.1007/s12274-014-0632-7
Cite this article:
Gu J, Lan G, Jiang Y, et al. Shaped Pt-Ni nanocrystals with an ultrathin Pt-enriched shell derived from one-pot hydrothermal synthesis as active electrocatalysts for oxygen reduction. Nano Research, 2015, 8(5): 1480-1496. https://doi.org/10.1007/s12274-014-0632-7

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Received: 03 September 2014
Revised: 21 October 2014
Accepted: 03 November 2014
Published: 01 December 2014
© Tsinghua University Press and Springer-Verlag Berlin Heidelberg 2014
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