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Double-atom catalysts as a molecular platform for heterogeneous oxygen evolution electrocatalysis

Nature Energy volume 6, pages 1054–1066 (2021)Cite this article

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Abstract

The oxygen evolution reaction (OER) is an essential anode reaction for the generation of fuels through water splitting or CO2 electroreduction. Mixed metal oxides containing Co, Fe or Ni have proved to be the most promising OER electrocatalysts in alkaline media. However, the active sites and reaction mechanisms of these catalysts are difficult to study due to their heterogeneous nature. Here we describe a general synthesis of Co-, Fe- and Ni-containing double-atom catalysts from their single-atom precursors via in situ electrochemical transformation. Characterization reveals molecule-like bimetallic active sites for these supported catalysts. For each catalyst, we propose a catalytic cycle; all exhibit bimetallic cooperation and follow a similar O–O bond-forming step. However, the mechanisms diverge in the site and source of OH− for O–O bond formation, as well as the order of proton and electron transfer. Our work demonstrates double-atom catalysts as an attractive platform for fundamental studies of heterogeneous OER electrocatalysts.

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Fig. 1: Electrochemical OER performance of double-atom catalysts and single-atom precatalysts.
Fig. 2: Operando XAS study of Ni–Fe–N–C.
Fig. 3: Structural evolution and change of the oxidation state of double atoms.
Fig. 4: Operando HERFD–XAS experiments of Ni–Fe–N–C.
Fig. 5: Potential dependent TOFs of different catalysts.
Fig. 6: Preferred proposed reaction mechanisms of OER for double-atom catalysts.

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We declare that all data supporting the findings of this study are available in the paper and Supplementary Information files. Source data are provided with this paper.

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Acknowledgements

This work is supported by the European Research Council (grant no. 681292) and the Ministry of Science and Technology, Taiwan (contract no. MOST 107-2628-M-002-015-RSP). We thank the following individuals from EPFL for experimental assistance: W. Ni (X-ray diffraction and Raman spectra), J. Gu (electrochemical setup for O2 Faradaic efficiency measurements), W. Lan and J. Luterbacher (N2 adsorption), P. Mettraux (XPS) and N. Gasilova (ICP–AES). Y.-F. Liao (NSRRC) is acknowledged for help with operando XAS. S. Sun (EPFL) is acknowledged for the help with processing some figures.

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Author notes

  1. These authors contributed equally: Lichen Bai, Chia-Shuo Hsu.

Authors and Affiliations

  1. Laboratory of Inorganic Synthesis and Catalysis, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), EPFL-ISIC-LSCI, BCH 3305, Lausanne, Switzerland

    Lichen Bai & Xile Hu

  2. Department of Chemistry, National Taiwan University, Taipei, Taiwan

    Chia-Shuo Hsu & Hao Ming Chen

  3. Interdisciplinary Centre for Electron Microscopy (CIME), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland

    Duncan T. L. Alexander

  4. Electron Spectrometry and Microscopy Laboratory (LSME), Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland

    Duncan T. L. Alexander

  5. National Synchrotron Radiation Research Center (NSRRC), Hsinchu, Taiwan

    Hao Ming Chen

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Contributions

L.B. performed the synthesis, most of the characterization, electrochemical tests and electrokinetic analysis. C.-S.H. performed the operando X-ray absorption experiments. D.T.L.A. and L.B. performed the spherical aberration-corrected HAADF–STEM measurements. All authors analysed the data. L.C.B. and X.H. wrote the paper, with inputs from other authors. H.M.C. and X.H directed the research.

Corresponding authors

Correspondence to Hao Ming Chen or Xile Hu.

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Peer review information Nature Energy thanks Marcel Risch and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Bai, L., Hsu, CS., Alexander, D.T.L. et al. Double-atom catalysts as a molecular platform for heterogeneous oxygen evolution electrocatalysis. Nat Energy 6, 1054–1066 (2021). https://doi.org/10.1038/s41560-021-00925-3

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