Dynamically Unveiling Metal–Nitrogen Coordination during Thermal Activation to Design High-Efficient Atomically Dispersed CoN4 Active Sites

Yanghua He; Qiurong Shi; Weitao Shan; Xing Li; A. Jeremy Kropf; Evan C. Wegener; Joshua Wright; Stavros Karakalos; Dong Su; David A. Cullen; Guofeng Wang; Deborah J. Myers; Gang Wu

doi:10.1002/anie.202017288

Dynamically Unveiling Metal–Nitrogen Coordination during Thermal Activation to Design High-Efficient Atomically Dispersed CoN₄ Active Sites

Yanghua He, Qiurong Shi, Weitao Shan, Xing Li, A. Jeremy Kropf, Evan C. Wegener, Joshua Wright, Stavros Karakalos, Dong Su, David A. Cullen, Guofeng Wang, Deborah J. Myers, Gang Wu

Materials MicroAnalysis

Research output: Contribution to journal › Article › peer-review

140 Scopus citations

Abstract

We elucidate the structural evolution of CoN₄ sites during thermal activation by developing a zeolitic imidazolate framework (ZIF)-8-derived carbon host as an ideal model for Co²⁺ ion adsorption. Subsequent in situ X-ray absorption spectroscopy analysis can dynamically track the conversion from inactive Co−OH and Co−O species into active CoN₄ sites. The critical transition occurs at 700 °C and becomes optimal at 900 °C, generating the highest intrinsic activity and four-electron selectivity for the oxygen reduction reaction (ORR). DFT calculations elucidate that the ORR is kinetically favored by the thermal-induced compressive strain of Co−N bonds in CoN₄ active sites formed at 900 °C. Further, we developed a two-step (i.e., Co ion doping and adsorption) Co-N-C catalyst with increased CoN₄ site density and optimized porosity for mass transport, and demonstrated its outstanding fuel cell performance and durability.

Original language	English
Pages (from-to)	9516-9526
Number of pages	11
Journal	Angewandte Chemie - International Edition
Volume	60
Issue number	17
DOIs	https://doi.org/10.1002/anie.202017288
State	Published - Apr 19 2021

Funding

The authors acknowledge the U.S. Department of Energy, Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office (DOE‐EERE‐HFTO) through the Electrocatalysis Consortium (ElectroCat) and the DOE program managers, Dimitrios Papageorgopoulos and David Peterson. Argonne National Laboratory's work is supported by DOE‐EERE‐HFTO under contract DE‐AC02‐06CH11357. The XAS experiments were performed at the Advanced Photon Source (APS), a DOE Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory, also under Contract No. DE‐AC02‐06CH11357. The operation of MRCAT at the APS is supported by the DOE the MRCAT member institutions. G. Wu also thanks the support from National Science Foundation (CBET‐1604392, 1804326). The authors acknowledge the U.S. Department of Energy, Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office (DOE-EERE-HFTO) through the Electrocatalysis Consortium (ElectroCat) and the DOE program managers, Dimitrios Papageorgopoulos and David Peterson. Argonne National Laboratory's work is supported by DOE-EERE-HFTO under contract DE-AC02-06CH11357. The XAS experiments were performed at the Advanced Photon Source (APS), a DOE Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory, also under Contract No. DE-AC02-06CH11357. The operation of MRCAT at the APS is supported by the DOE the MRCAT member institutions. G. Wu also thanks the support from National Science Foundation (CBET-1604392, 1804326).

Keywords

Co-N-C
fuel cells
in situ XAS
oxygen reduction reaction
single metal site

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1002/anie.202017288

Cite this

He, Y., Shi, Q., Shan, W., Li, X., Kropf, A. J., Wegener, E. C., Wright, J., Karakalos, S., Su, D., Cullen, D. A., Wang, G., Myers, D. J., & Wu, G. (2021). Dynamically Unveiling Metal–Nitrogen Coordination during Thermal Activation to Design High-Efficient Atomically Dispersed CoN₄ Active Sites. Angewandte Chemie - International Edition, 60(17), 9516-9526. https://doi.org/10.1002/anie.202017288

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abstract = "We elucidate the structural evolution of CoN4 sites during thermal activation by developing a zeolitic imidazolate framework (ZIF)-8-derived carbon host as an ideal model for Co2+ ion adsorption. Subsequent in situ X-ray absorption spectroscopy analysis can dynamically track the conversion from inactive Co−OH and Co−O species into active CoN4 sites. The critical transition occurs at 700 °C and becomes optimal at 900 °C, generating the highest intrinsic activity and four-electron selectivity for the oxygen reduction reaction (ORR). DFT calculations elucidate that the ORR is kinetically favored by the thermal-induced compressive strain of Co−N bonds in CoN4 active sites formed at 900 °C. Further, we developed a two-step (i.e., Co ion doping and adsorption) Co-N-C catalyst with increased CoN4 site density and optimized porosity for mass transport, and demonstrated its outstanding fuel cell performance and durability.",

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He, Y, Shi, Q, Shan, W, Li, X, Kropf, AJ, Wegener, EC, Wright, J, Karakalos, S, Su, D, Cullen, DA, Wang, G, Myers, DJ & Wu, G 2021, 'Dynamically Unveiling Metal–Nitrogen Coordination during Thermal Activation to Design High-Efficient Atomically Dispersed CoN₄ Active Sites', Angewandte Chemie - International Edition, vol. 60, no. 17, pp. 9516-9526. https://doi.org/10.1002/anie.202017288

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AU - He, Yanghua

AU - Shi, Qiurong

AU - Shan, Weitao

AU - Li, Xing

AU - Kropf, A. Jeremy

AU - Wegener, Evan C.

AU - Wright, Joshua

AU - Karakalos, Stavros

AU - Su, Dong

AU - Cullen, David A.

AU - Wang, Guofeng

AU - Myers, Deborah J.

AU - Wu, Gang

PY - 2021/4/19

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N2 - We elucidate the structural evolution of CoN4 sites during thermal activation by developing a zeolitic imidazolate framework (ZIF)-8-derived carbon host as an ideal model for Co2+ ion adsorption. Subsequent in situ X-ray absorption spectroscopy analysis can dynamically track the conversion from inactive Co−OH and Co−O species into active CoN4 sites. The critical transition occurs at 700 °C and becomes optimal at 900 °C, generating the highest intrinsic activity and four-electron selectivity for the oxygen reduction reaction (ORR). DFT calculations elucidate that the ORR is kinetically favored by the thermal-induced compressive strain of Co−N bonds in CoN4 active sites formed at 900 °C. Further, we developed a two-step (i.e., Co ion doping and adsorption) Co-N-C catalyst with increased CoN4 site density and optimized porosity for mass transport, and demonstrated its outstanding fuel cell performance and durability.

AB - We elucidate the structural evolution of CoN4 sites during thermal activation by developing a zeolitic imidazolate framework (ZIF)-8-derived carbon host as an ideal model for Co2+ ion adsorption. Subsequent in situ X-ray absorption spectroscopy analysis can dynamically track the conversion from inactive Co−OH and Co−O species into active CoN4 sites. The critical transition occurs at 700 °C and becomes optimal at 900 °C, generating the highest intrinsic activity and four-electron selectivity for the oxygen reduction reaction (ORR). DFT calculations elucidate that the ORR is kinetically favored by the thermal-induced compressive strain of Co−N bonds in CoN4 active sites formed at 900 °C. Further, we developed a two-step (i.e., Co ion doping and adsorption) Co-N-C catalyst with increased CoN4 site density and optimized porosity for mass transport, and demonstrated its outstanding fuel cell performance and durability.

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