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Surface evolution of a Pt–Pd–Au electrocatalyst for stable oxygen reduction

Nature Energy volume 2, Article number: 17111 (2017) | Download Citation

Abstract

Core–shell nanocatalysts have demonstrated potential as highly active low-Pt fuel cell cathodes for the oxygen reduction reaction (ORR); however, challenges remain in optimizing their surface and interfacial structures, which often exhibit undesirable structural degradation and poor durability. Here, we construct an unsupported nanoporous catalyst with a Pt–Pd shell of sub-nanometre thickness on Au, which demonstrates an initial ORR activity of 1.140 A mgPt−1 at 0.9 V. The activity increases to 1.471 A mgPt−1 after 30,000 potential cycles and is stable over a further 70,000 cycles. Using aberration-corrected scanning transmission electron microscopy and atomically resolved elemental mapping, the origin of the activity change is revealed to be an atomic-scale evolution of the shell from an initial Pt–Pd alloy into a bilayer structure with a Pt-rich trimetallic surface, and finally into a uniform and stable Pt–Pd–Au alloy. This Pt–Pd–Au alloy possesses a suitable configuration for ORR, giving a relatively low free energy change for the final water formation from adsorbed OH intermediate during the reaction.

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Acknowledgements

We thank JEOL Ltd. and FEI Ltd. for their generous supports to the STEM and EDS analyses. This work was financially supported by the National 973 Program Project of China (2012CB932800), the National Natural Science Foundation of China (51572016, 51671145 and U1530401), the National Program for Thousand Young Talents of China, the Tianjin Municipal Education Commission, the Tianjin Municipal Science and Technology Commission, and the Fundamental Research Funds of Tianjin University of Technology. Y.D. also acknowledges the Fundamental Research Funds of Shandong University for sponsoring this research. J.Luo acknowledges useful discussions with X. Ke. L.-M.L. gratefully acknowledges the computational support from the Beijing Computational Science Research Center (CSRC) and Guangdong Supercomputer.

Author information

Author notes

    • Jian Li
    • , Hui-Ming Yin
    • , Xi-Bo Li
    •  & Eiji Okunishi

    These authors contributed equally to this work.

Affiliations

  1. Tianjin Key Laboratory of Advanced Functional Porous Materials and Center for Electron Microscopy, School of Materials Science and Engineering, Tianjin University of Technology, Tianjin 300384, China

    • Jian Li
    • , Hui-Ming Yin
    • , Yong-Li Shen
    • , Jia He
    • , Wen-Xin Wang
    • , Chao Li
    • , Jun Luo
    •  & Yi Ding
  2. Beijing Computational Science Research Center, Beijing 100084, China

    • Xi-Bo Li
    • , Zhen-Kun Tang
    •  & Li-Min Liu
  3. JEOL Ltd., 1-2 Musashino, 3-Chome Akishima, 196-8558 Tokyo, Japan

    • Eiji Okunishi
  4. NanoPort Europe, FEI Company BV, PO Box 80066, 5600KA Eindhoven, The Netherlands

    • Emrah Yücelen
  5. Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China

    • Yue Gong
    •  & Lin Gu
  6. Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China

    • Shu Miao

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Contributions

Y.D., J.Luo and L.-M.L. co-supervised the whole work. Y.D. conceived and designed the electrocatalysts and the electrochemical experiments. J.Li and W.-X.W. performed the sample preparation and the electrochemical experiments. X.-B.L. performed the first-principles calculations, to which Z.-K.T. contributed. L.-M.L. conducted and analysed the calculations. J.Luo proposed the STEM and elemental mapping experiments and performed the analysis and evaluation thereof, to which C.L., Y.G., L.G. and S.M. contributed. E.O. and E.Y. operated the aberration-corrected JEOL and FEI STEM instruments, respectively. Y.D., H.-M.Y. and J.Li analysed the results of the electrochemical experiments, and Y.-L.S. and J.H. contributed to the discussion thereof. J.Li, H.-M.Y., Y.D., J.Luo and L.-M.L. prepared the figures and co-wrote the manuscript. All authors discussed the results, drew conclusions and commented on the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Li-Min Liu or Jun Luo or Yi Ding.

Supplementary information

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    Supplementary Information

    Supplementary Methods, Supplementary Tables 1–3, Supplementary Figures 1–17.

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    POSCAR file containing information on the supercell and atomic positions for the DFT calculations with Pt.

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DOI

https://doi.org/10.1038/nenergy.2017.111