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Atomically dispersed bimetallic Fe–Co electrocatalysts for green production of ammonia

Abstract

The dominant Haber–Bosch process to produce ammonia, arguably the most important chemical in support of global food supply, is both energy and carbon intensive, resulting in substantial environmental impacts. Electrocatalytic nitrogen reduction reaction (NRR) powered by renewable electricity provides a green synthetic route for ammonia, but still suffers from insufficient yield rate and Faradaic efficiency. Single-atom electrocatalysts (SACs) have the potential to transform this catalytic process; however, controllable synthesis of SACs with high loading of active sites remains a big challenge. Here we utilize bacterial cellulose with rich oxygen functional groups to anchor iron (Fe) and cobalt (Co), realizing high density, atomically dispersed, bimetallic Fe–Co active sites. For electrocatalytic NRR, our catalyst design delivers a remarkable ammonia yield rate of 579.2 ± 27.8 μg h−1 mgcat.−1 and an exceptional Faradaic efficiency of 79.0 ± 3.8%. The combined theoretical and experimental investigations reveal that the operando change in coordination configuration from [(O-C2)3Fe–Co(O-C2)3] to [(O-C2)3Fe–Co(O-C)C2] is the enabling chemistry. Our findings suggest a general approach to engineer SACs that can drive critical reactions of relevance for sustainability.

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Fig. 1: Controllable synthesis of bimetallic Fe–Co SAs.
Fig. 2: Bimetallic Fe–Co site configuration.
Fig. 3: NRR performance on the electrocatalyst-loaded GC disk electrode with a loading density of 0.50 mg cm−2.
Fig. 4: NRR performance on GC plate electrode.
Fig. 5: NRR activity origin of bimetallic Fe–Co site.

Data availability

All data that support the findings in this paper are available within the article and its Supplementary Information. Source data are available from the corresponding author upon reasonable request.

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Acknowledgements

H.Z. acknowledges funding support from the Natural Science Foundation of China (grant no. 52172106 and 51872292). M.H. acknowledges funding support from the Natural Science Foundation of China (grant no. 61804154). Y.L. acknowledges funding support from the Natural Science Foundation of China (grant no. 52122212), Youth Innovation Promotion Association of the CAS (grant no. 2020458) and National Key Research and Development Program of China (grant no. 2019YFA0307900). S.Z. acknowledges funding support from Anhui Provincial Natural Science Foundation (grant no. 2108085QB60), CASHIPS Director’s Fund (grant no. YZJJ2021QN18), China Postdoctoral Science Foundation (grant no. 2020M682057) and Special Research Assistant Program, Chinese Academy of Sciences. This work is also supported by the CAS/SAFEA International Partnership Program for Creative Research Teams of Chinese Academy of Sciences, China. This work was carried out with the support of 1W1B beamline at Beijing Synchrotron Radiation Facility. The computation work was carried out at LvLiang Cloud Computing Centre of China and the DFT calculations were performed on TianHe-2.

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H. Zhao and H. Zhang conceived the concept and designed the experiments. S.Z. fabricated the catalysts and performed the material characterization and electrochemical measurements. M.H. conducted DFT calculations. L.R.Z. carried out the EXAFS measurements and T.S. analysed the EXAFS results. Y.L. performed the STEM measurements. X.Z., H. Zhou, C.C., Y.Z., G.W. and H.Y. contributed to the experimental design. H. Zhao and H. Zhang supervised the research. H. Zhao, H. Zhang and S.Z. co-wrote the manuscript. All authors discussed the results and commented on the manuscript.

Corresponding authors

Correspondence to Haimin Zhang or Huijun Zhao.

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Nature Sustainability thanks Rui Si and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary Figs. 1–39, Tables 1–6 and refs. 1–69.

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Zhang, S., Han, M., Shi, T. et al. Atomically dispersed bimetallic Fe–Co electrocatalysts for green production of ammonia. Nat Sustain (2022). https://doi.org/10.1038/s41893-022-00993-7

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