To achieve the US Department of Energy 2018 target set for platinum-group metal-free catalysts (PGM-free catalysts) in proton exchange membrane fuel cells, the low density of active sites must be overcome. Here, we report a class of concave Fe–N–C single-atom catalysts possessing an enhanced external surface area and mesoporosity that meets the 2018 PGM-free catalyst activity target, and a current density of 0.047 A cm–2 at 0.88 ViR-free under 1.0 bar H2–O2. This performance stems from the high density of active sites, which is realized through exposing inaccessible Fe–N4 moieties (that is, increasing their utilization) and enhancing the mass transport of the catalyst layer. Further, we establish structure–property correlations that provide a route for designing highly efficient PGM-free catalysts for practical application, achieving a power density of 1.18 W cm−2 under 2.5 bar H2–O2, and an activity of 129 mA cm−2 at 0.8 ViR-free under 1.0 bar H2–air.
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The data that support the plots within this paper and other findings of this study are available from the corresponding author on reasonable request.
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This work was supported by the National Thousand Talents Plan of China, the National Natural Science Foundation of China (grant no. 21673014), the 111 project (B17002) funded by the Ministry of Education of China and the Fundamental Research Funds for the Central Universities of China. The authors thank D. N. Futaba (AIST, Japan) for language polishing.
The authors declare no competing interests.
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Wan, X., Liu, X., Li, Y. et al. Fe–N–C electrocatalyst with dense active sites and efficient mass transport for high-performance proton exchange membrane fuel cells. Nat Catal 2, 259–268 (2019). https://doi.org/10.1038/s41929-019-0237-3
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