Fe–N–C electrocatalyst with dense active sites and efficient mass transport for high-performance proton exchange membrane fuel cells


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.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: Synthesis and morphology characterization of TPI@Z8(SiO2)-650-C.
Fig. 2: Characterization of active site coordination of TPI@Z8(SiO2)-650-C.
Fig. 3: PEMFC performance measurements.
Fig. 4: Quantification of SD and its relationship with the fuel cell current density.
Fig. 5: PEMFC activity comparison between TPI@Z8(SiO2)-650-C and the literature.

Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding author on reasonable request.


  1. 1.

    Debe, M. K. Electrocatalyst approaches and challenges for automotive fuel cells. Nature 486, 43–51 (2012).

    CAS  Article  Google Scholar 

  2. 2.

    Shao, M., Chang, Q., Dodelet, J.-P. & Chenitz, R. Recent advances in electrocatalysts for oxygen reduction reaction. Chem. Rev. 116, 3594–3657 (2016).

    CAS  Article  Google Scholar 

  3. 3.

    Wu, G., More, K. L., Johnston, C. M. & Zelenay, P. High-performance electrocatalysts for oxygen reduction derived from polyaniline, iron, and cobalt. Science 332, 443–447 (2011).

    CAS  Article  Google Scholar 

  4. 4.

    Gasteiger, H. A., Kocha, S. S., Sompalli, B. & Wagner, F. T. Activity benchmarks and requirements for Pt, Pt-alloy, and non-Pt oxygen reduction catalysts for PEMFCs. Appl. Catal. B 56, 9–35 (2005).

    CAS  Article  Google Scholar 

  5. 5.

    Chen, C. et al. Highly crystalline multimetallic nanoframes with three-dimensional electrocatalytic surfaces. Science 343, 1339–1343 (2014).

    CAS  Article  Google Scholar 

  6. 6.

    Bian, T. et al. Epitaxial growth of twinned Au–Pt core-shell star-shaped decahedra as highly durable electrocatalysts. Nano Lett. 15, 7808–7815 (2015).

    CAS  Article  Google Scholar 

  7. 7.

    Zhang, L., Wilkinson, D. P., Liu, Y. & Zhang, J. Progress in nanostructured (Fe or Co)/N/C non-noble metal electrocatalysts for fuel cell oxygen reduction reaction. Electrochim. Acta 262, 326–336 (2018).

    Article  Google Scholar 

  8. 8.

    Xia, B. Y. et al. A metal–organic framework-derived bifunctional oxygen electrocatalyst. Nat. Energy 1, 15006 (2016).

    CAS  Article  Google Scholar 

  9. 9.

    Zheng, Y. et al. Molecule-level g-C3N4 coordinated transition metals as a new class of electrocatalysts for oxygen electrode reactions. J. Am. Chem. Soc. 139, 3336–3339 (2017).

    CAS  Article  Google Scholar 

  10. 10.

    Wang, J. et al. Design of N-coordinated dual-metal sites: a stable and active Pt-free catalyst for acidic oxygen reduction reaction. J. Am. Chem. Soc. 139, 17281–17284 (2017).

    CAS  Article  Google Scholar 

  11. 11.

    Strickland, K. et al. Highly active oxygen reduction non-platinum group metal electrocatalyst without direct metal-nitrogen coordination. Nat. Commun. 6, 7343 (2015).

    CAS  Article  Google Scholar 

  12. 12.

    Multi-Year Research, Development, and Demonstration Plan (US Department of Energy, Fuel Cell Technologies Office, 2017).

  13. 13.

    Singh, K., Razmjooei, F. & Yu, J.-S. Active sites and factors influencing them for efficient oxygen reduction reaction in metal-N coordinated pyrolyzed and non-pyrolyzed catalysts: a review. J. Mater. Chem. A 5, 20095–20119 (2017).

    CAS  Article  Google Scholar 

  14. 14.

    Kramm, U. I., Lefèvre, M., Larouche, N., Schmeisser, D. & Dodelet, J.-P. Correlations between mass activity and physicochemical properties of Fe/N/C catalysts for the ORR in PEM fuel cell via 57Fe Mössbauer spectroscopy and other techniques. J. Am. Chem. Soc. 136, 978–985 (2014).

    CAS  Article  Google Scholar 

  15. 15.

    Zitolo, A. et al. Identification of catalytic sites for oxygen reduction in iron- and nitrogen-doped graphene materials. Nat. Mater. 14, 937–942 (2015).

    CAS  Article  Google Scholar 

  16. 16.

    Sahraie, N. R. et al. Quantifying the density and utilization of active sites in non-precious metal oxygen electroreduction catalysts. Nat. Commun. 6, 8618 (2015).

    CAS  Article  Google Scholar 

  17. 17.

    Li, J. et al. Structural and mechanistic basis for the high activity of Fe–N–C catalysts toward oxygen reduction. Energy Environ. Sci. 9, 2418–2432 (2016).

    CAS  Article  Google Scholar 

  18. 18.

    Jia, Q. et al. Spectroscopic insights into the nature of active sites in iron–nitrogen–carbon electrocatalysts for oxygen reduction in acid. Nano Energy 29, 65–82 (2016).

    CAS  Article  Google Scholar 

  19. 19.

    Chen, Y. et al. Isolated single iron atoms anchored on N-doped porous carbon as an efficient electrocatalyst for the oxygen reduction reaction. Angew. Chem. Int. Ed. 56, 6937–6941 (2017).

    CAS  Article  Google Scholar 

  20. 20.

    Fei, H. et al. General synthesis and definitive structural identification of MN4C4 single-atom catalysts with tunable electrocatalytic activities. Nat. Catal. 1, 63–72 (2018).

    Article  Google Scholar 

  21. 21.

    Zhang, H. et al. Single atomic iron catalysts for oxygen reduction in acidic media: particle size control and thermal activation. J. Am. Chem. Soc. 139, 14143–14149 (2017).

    CAS  Article  Google Scholar 

  22. 22.

    Chen, X., Yu, L., Wang, S., Deng, D. & Bao, X. Highly active and stable single iron site confined in graphene nanosheets for oxygen reduction reaction. Nano Energy 32, 353–358 (2017).

    CAS  Article  Google Scholar 

  23. 23.

    Liu, Q., Liu, X., Zheng, L. & Shui, J. The solid-phase synthesis of an Fe–N–C electrocatalyst for high-power proton-exchange membrane fuel cells. Angew. Chem. Int. Ed. 57, 1204–1208 (2018).

    CAS  Article  Google Scholar 

  24. 24.

    Wan, X. et al. Synthesis and active site identification of Fe−N−C single-atom catalysts for the oxygen reduction reaction. ChemElectroChem 6, 304–315 (2019).

    CAS  Article  Google Scholar 

  25. 25.

    Jaouen, F., Lefèvre, M., Dodelet, J.-P. & Cai, M. Heat-treated Fe/N/C catalysts for O2 electroreduction: are active sites hosted in micropores? J. Phys. Chem. B 110, 5553–5558 (2006).

    CAS  Article  Google Scholar 

  26. 26.

    Ye, Y. et al. Surface functionalization of ZIF-8 with ammonium ferric citrate toward high exposure of Fe-N active sites for efficient oxygen and carbon dioxide electroreduction. Nano Energy 38, 281–289 (2017).

    CAS  Article  Google Scholar 

  27. 27.

    Fu, X. et al. In situ polymer graphenization ingrained with nanoporosity in a nitrogenous electrocatalyst boosting the performance of polymer-electrolyte-membrane fuel cells. Adv. Mater. 29, 1700363 (2017).

    Google Scholar 

  28. 28.

    Pampel, J. & Fellinger, T.-P. Opening of bottleneck pores for the improvement of nitrogen doped carbon electrocatalysts. Adv. Energy Mater. 6, 1502389 (2016).

    Article  Google Scholar 

  29. 29.

    Malko, D., Kucernak, A. & Lopes, T. In situ electrochemical quantification of active sites in Fe–N/C non-precious metal catalysts. Nat. Commun. 7, 13285 (2016).

    CAS  Article  Google Scholar 

  30. 30.

    O’Hayre, R., Barnett, D. M. & Prinz, F. B. The triple phase boundary a mathematical model and experimental investigations for fuel cells. J. Electrochem. Soc. 152, A439 (2005).

    Article  Google Scholar 

  31. 31.

    Seh, Z. W. et al. Combining theory and experiment in electrocatalysis: insights into materials design. Science 355, eaad4998 (2017).

    Article  Google Scholar 

  32. 32.

    Proietti, E. et al. Iron-based cathode catalyst with enhanced power density in polymer electrolyte membrane fuel cells. Nat. Commun. 2, 416 (2011).

    Article  Google Scholar 

  33. 33.

    Antonacci, P. et al. Balancing mass transport resistance and membrane resistance when tailoring microporous layer thickness for polymer electrolyte membrane fuel cells operating at high current densities. Electrochim. Acta 188, 888–897 (2016).

    CAS  Article  Google Scholar 

  34. 34.

    Chenitz, R. et al. A specific demetalation of Fe–N4 catalytic sites in the micropores of NC_Ar + NH3 is at the origin of the initial activity loss of the highly active Fe/N/C catalyst used for the reduction of oxygen in PEM fuel cells. Energy Environ. Sci. 11, 365–382 (2018).

    CAS  Article  Google Scholar 

  35. 35.

    Zeng, X. et al. Single-atom to single-atom grafting of Pt1 onto Fe–N4 center: Pt1@Fe–N–C multifunctional electrocatalyst with significantly enhanced properties. Adv. Energy Mater. 8, 1701345 (2018).

    Article  Google Scholar 

  36. 36.

    Charreteur, F., Ruggeri, S., Jaouen, F. & Dodelet, J. P. Increasing the activity of Fe/N/C catalysts in PEM fuel cell cathodes using carbon blacks with a high-disordered carbon content. Electrochim. Acta 53, 6881–6889 (2008).

    CAS  Article  Google Scholar 

  37. 37.

    Lefèvre, M., Proietti, E., Jaouen, F. & Dodelet, J.-P. Iron-based catalysts with improved oxygen reduction activity in polymer electrolyte fuel cells. Science 324, 71–74 (2009).

    Article  Google Scholar 

  38. 38.

    Meng, H. et al. Iron porphyrin-based cathode catalysts for polymer electrolyte membrane fuel cells: effect of NH3 and Ar mixtures as pyrolysis gases on catalytic activity and stability. Electrochim. Acta 55, 6450–6461 (2010).

    CAS  Article  Google Scholar 

  39. 39.

    Jaouen, F. et al. Oxygen reduction activities compared in rotating-disk electrode and proton exchange membrane fuel cells for highly active Fe–N–C catalysts. Electrochim. Acta 87, 619–628 (2013).

    CAS  Article  Google Scholar 

  40. 40.

    Afsahi, F. & Kaliaguine, S. Non-precious electrocatalysts synthesized from metal–organic frameworks. J. Mater. Chem. A 2, 12270 (2014).

    CAS  Article  Google Scholar 

  41. 41.

    Zhu, Q.-L., Xia, W., Akita, T., Zou, R. & Xu, Q. Metal-organic framework-derived honeycomb-like open porous nanostructures as precious-metal-free catalysts for highly efficient oxygen electroreduction. Adv. Mater. 28, 6391–6398 (2016).

    CAS  Article  Google Scholar 

  42. 42.

    Shui, J., Chen, C., Grabstanowicz, L., Zhao, D. & Liu, D.-J. Highly efficient nonprecious metal catalyst prepared with metal-organic framework in a continuous carbon nanofibrous network. Proc. Natl Acad. Sci. USA 112, 10629–10634 (2015).

    CAS  Article  Google Scholar 

  43. 43.

    Armel, V. et al. Structural descriptors of zeolitic-imidazolate frameworks are keys to the activity of Fe–N–C catalysts. J. Am. Chem. Soc. 139, 453–464 (2016).

    Article  Google Scholar 

  44. 44.

    Zhou, B. et al. Ferrocene-based porous organic polymer derived high-performance electrocatalysts for oxygen reduction. J. Mater. Chem. A 5, 22163–22169 (2017).

    CAS  Article  Google Scholar 

  45. 45.

    Zhao, D. et al. Highly efficient non-precious metal electrocatalysts prepared from one-pot synthesized zeolitic imidazolate frameworks. Adv. Mater. 26, 1093–1097 (2014).

    CAS  Article  Google Scholar 

  46. 46.

    Tian, J. et al. Optimized synthesis of Fe/N/C cathode catalysts for PEM fuel cells: a matter of iron-ligand coordination strength. Angew. Chem. Int. Ed. 52, 6867–6870 (2013).

    CAS  Article  Google Scholar 

  47. 47.

    Zhao, D. et al. Iron imidazolate framework as precursor for electrocatalysts in polymer electrolyte membrane fuel cells. Chem. Sci. 3, 3200–3205 (2012).

    CAS  Article  Google Scholar 

  48. 48.

    Yuan, S. et al. A highly active and support-free oxygen reduction catalyst prepared from ultrahigh-surface-area porous polyporphyrin. Angew. Chem. Int. Ed. 52, 8349–8533 (2013).

    CAS  Article  Google Scholar 

  49. 49.

    Chung, H. T. et al. Direct atomic-level insight into the active sites of a high-performance PGM-free ORR catalyst. Science 357, 479–484 (2017).

    CAS  Article  Google Scholar 

  50. 50.

    Wang, X. X. et al. Nitrogen-coordinated single cobalt atom catalysts for oxygen reduction in proton exchange membrane fuel cells. Adv. Mater. 30, 1706758 (2018).

    Article  Google Scholar 

  51. 51.

    He, Y. et al. Highly active atomically dispersed CoN4 fuel cell cathode catalysts derived from surfactant-assisted MOFs: carbon-shell confinement strategy. Energy Environ. Sci. 12, 250–260 (2019).

  52. 52.

    Li, J. et al. Atomically dispersed manganese catalysts for oxygen reduction in proton-exchange membrane fuel cells. Nat. Catal. 1, 935–945 (2018).

    Article  Google Scholar 

  53. 53.

    Shang, L. et al. Well-dispersed ZIF-derived Co,N-co-doped carbon nanoframes through mesoporous-silica-protected calcination as efficient oxygen reduction electrocatalysts. Adv. Mater. 28, 1668–1674 (2016).

    CAS  Article  Google Scholar 

  54. 54.

    Gor, G. Y., Thommes, M., Cychosz, K. A. & Neimark, A. V. Quenched solid density functional theory method for characterization of mesoporous carbons by nitrogen adsorption. Carbon 50, 1583–1590 (2012).

    CAS  Article  Google Scholar 

  55. 55.

    Newville, M. IFEFFIT: interactive XAFS analysis and FEFF fitting. J. Synchrotron Radiat. 8, 322–324 (2001).

    CAS  Article  Google Scholar 

  56. 56.

    Ravel, B. & Newville, M. ATHENA, ARTEMIS, HEPHAESTUS: data analysis for X-ray absorption spectroscopy using IFEFFIT. J. Synchrotron Radiat. 12, 537–541 (2005).

    CAS  Article  Google Scholar 

Download references


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.

Author information




X.W. and J.S. conceived the idea. X.W. performed the synthesis, electrochemical tests and characterizations. H.W. performed TEM characterizations. X.L. performed XAS measurement and analysis. L.Z. and W.Y provided expertise for XAS analysis. Y.L. provided the structural models for XAS analysis. R.Y. and J.S. supervised the project and participated in the planning of research. X.W., X.L., M.X. and J.S. co-wrote the paper. All authors discussed the results and commented on the manuscript.

Corresponding authors

Correspondence to Ming Xu or Jianglan Shui.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Figures 1–41, Supplementary Tables 1–8 and Supplementary Note.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

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

Download citation

Further reading