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Activity versus stability of atomically dispersed transition-metal electrocatalysts

Nature Reviews Materials volume 9, pages 643–656 (2024)Cite this article

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Abstract

Polymer electrolyte fuel cells operating on clean and sustainable hydrogen are an attractive solution for clean transportation. However, polymer electrolyte fuel cells are costly owing to the use of considerable amounts of platinum group metal (PGM) catalysts, which are needed to catalyse the very slow oxygen reduction reaction at the cathode. The most attractive path in that regard is a complete replacement of precious metal catalysts by PGM-free materials with similar or better performance. Since 2010, numerous promising catalysts have been proposed for PGM-free electrocatalysis. However, the best-performing catalysts do not yet meet the requirements of practical systems. One important hurdle in catalyst discovery is relying heavily on empirical rather than rational design-based approaches. This Perspective article focuses on the most promising PGM-free oxygen reduction reaction catalysts based on atomically dispersed, nitrogen-coordinated single-atom metal sites (M–N–C catalysts). We specifically concentrate on the active-site structure and critical factors governing catalytic activity and performance durability. We propose potentially effective strategies for improving performance by controlling the catalyst structure at the atomic scale, mesoscale and nanoscale. We highlight the importance of overcoming often-observed activity–stability trade-offs and the importance of advanced modelling for the rational design of catalysts.

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Fig. 1: Atomically dispersed, nitrogen-coordinated metal sites in Fe–N–C catalysts.
Fig. 2: Nitrogen coordination of single-atom metal sites governing catalytic activity and stability.
Fig. 3: Strategies for improving intrinsic and mass activity of M–N–C catalysts.
Fig. 4: Regulating nitrogen coordination and local structures to enhance stability.
Fig. 5: Activity and stability improvements of Fe–N–C catalysts.

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Acknowledgements

The authors acknowledge financial support from the US Department of Energy, Office of Energy Efficiency and Renewable Energy (EERE), Hydrogen and Fuel Cell Technologies Office through Electrocatalysis Consortium (ElectroCat). G.W. also acknowledges partial support from the National Science Foundation (CBET-1804326 and 2223467).

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  1. Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, NY, USA

    Gang Wu

  2. Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM, USA

    Piotr Zelenay

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Wu, G., Zelenay, P. Activity versus stability of atomically dispersed transition-metal electrocatalysts. Nat Rev Mater 9, 643–656 (2024). https://doi.org/10.1038/s41578-024-00703-z

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