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Microenvironment regulation of M-N-C single-atom catalysts towards oxygen reduction reaction

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Abstract

The development of cost-effective, robust, and durable electrocatalysts to replace the expensive Pt-based catalysts towards oxygen reduction reaction (ORR) is the trending frontier research topic in renewable energy and electrocatalysis. Particular attention has been paid to metal-nitrogen-carbon (M-N-C) single atom catalysts (SACs) due to their maximized atom utilization efficiency, biomimetic active site, and distinct electronic structure. More importantly, their catalytic properties can be further tailored by rationally regulating the microenvironment of active sites (i.e., M–N coordination number, heteroatom doping and substitution. Herein, we present a comprehensive summary of the recent advancement in the microenvironment regulation of M-N-C SACs towards improved ORR performance. The coordination environment manipulation regarding central metal and coordinated atoms is first discussed, focusing on the structure—function relationship. Apart from the near-range coordination, long-range substrate modulation including heteroatom doping, defect engineering is discussed as well. Besides, the synergy mechanism of nanoparticles and single atom sites to tune the electron cloud density at the active sites is summarized. Finally, we provide the challenges and outlook of the development of M-N-C SACs.

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References

  1. Pei, Y. F.; Song, H. Q.; Liu, Y.; Cheng, Y. J.; Li, W. D.; Chen, Y. M.; Fan, Y. P.; Liu, B. Z.; Lu, S. Y. Boron-nitrogen-doped carbon dots on multi-walled carbon nanotubes for efficient electrocatalysis of oxygen reduction reactions. J. Colloid Interface Sci. 2021, 600, 865–871.

    CAS  Google Scholar 

  2. Wu, X.; Meng, G.; Liu, W. X.; Li, T.; Yang, Q.; Sun, X. M.; Liu, J. F. Metal-organic framework-derived, Zn-doped porous carbon polyhedra with enhanced activity as bifunctional catalysts for rechargeable zinc-air batteries. Nano Res. 2018, 11, 163–173.

    CAS  Google Scholar 

  3. Liu, Z. H.; Du, Y.; Yu, R. H.; Zheng, M. B.; Hu, R.; Wu, J. S.; Xia, Y. Y.; Zhuang, Z. C.; Wang, D. S. Tuning mass transport in electrocatalysis down to Sub-5nm through nanoscale grade separation. Angew. Chem., Int. Ed. 2022, 62, e202212653.

    Google Scholar 

  4. Cheng, Q. Q.; Yang, S.; Fu, C. H.; Zou, L. L.; Zou, Z. Q.; Jiang, Z.; Zhang, J. L.; Yang, H. High-loaded sub-6 nm Pt1Co1 intermetallic compounds with highly efficient performance expression in PEMFCs. Energy Environ. Sci. 2022, 15, 278–286.

    CAS  Google Scholar 

  5. Li, Y. H.; Qu, Y. J.; Liu, C. C.; Cui, J. D.; Xu, K.; Li, Y.; Shen, H. Y.; Lu, Z. G.; Pan, H.; Xu, T. et al. Processing agricultural cornstalks toward high-efficient stable bifunctional ORR/OER electrocatalysts. Adv. Sustainable Syst. 2021, 6, 2100343.

    Google Scholar 

  6. Zhuang, Z. C.; Li, Y. H.; Yu, R. H.; Xia, L. X.; Yang, J. R.; Lang, Z. Q.; Zhu, J. X.; Huang, J. Z.; Wang, J. O.; Wang, Y. et al. Reversely trapping atoms from a perovskite surface for high-performance and durable fuel cell cathodes. Nat. Catal. 2022, 5, 300–310.

    CAS  Google Scholar 

  7. Zhuang, Z, C.; Li, Y.; Li, Y, H.; Huang, J. Z.; Wei, B.; Sun, R.; Ren, Y. J.; Ding, J.; Zhu, J. X.; Lang, Z. Q. et al. Atomically dispersed nonmagnetic electron traps improve oxygen reduction activity of perovskite oxides. Energy Environ. Sci. 2021, 14, 1016–1028.

    CAS  Google Scholar 

  8. Yang, Q.; Xiao, Z. C.; Kong, D. B.; Zhang, T. L.; Duan, X. G.; Zhou, S. K.; Niu, Y.; Shen, Y. D.; Sun, H. Q.; Wang, S. B. et al. New insight to the role of edges and heteroatoms in nanocarbons for oxygen reduction reaction. Nano Energy 2019, 66, 104096.

    CAS  Google Scholar 

  9. Zhao, S.; Yan, L. T.; Luo, H. M.; Mustain, W.; Xu, H. Recent progress and perspectives of bifunctional oxygen reduction/evolution catalyst development for regenerative anion exchange membrane fuel cells. Nano Energy 2018, 47, 172–198.

    CAS  Google Scholar 

  10. Wang, L. G.; Wang, D. S.; Li, Y. D. Single-atom catalysis for carbon neutrality. Carbon Energy 2022, 4, 1021–1079.

    CAS  Google Scholar 

  11. Gong, K. P.; Du, F.; Xia, Z. H.; Durstock, M.; Dai, L. M. Nitrogen-doped carbon nanotube arrays with high electrocatalytic activity for oxygen reduction. Science 2009, 323, 760–764.

    CAS  Google Scholar 

  12. Mehmood, A.; Gong, M. J.; Jaouen, F.; Roy, A.; Zitolo, A.; Khan, A.; Sougrati, M. T.; Primbs, M.; Bonastre, A. M.; Fongalland, D. et al. High loading of single atomic iron sites in Fe-N-C oxygen reduction catalysts for proton exchange membrane fuel cells. Nat. Catal. 2022, 5, 311–323.

    CAS  Google Scholar 

  13. Zhang, Z. Y.; Tan, Y. Y.; Zeng, T.; Yu, L. Y.; Chen, R. Z.; Cheng, N. C.; Mu, S. C.; Sun, X. L. Tuning the dual-active sites of ZIF-67 derived porous nanomaterials for boosting oxygen catalysis and rechargeable Zn-air batteries. Nano Res. 2020, 14, 2353–2362.

    Google Scholar 

  14. Xin, S. L.; Liu, Z. Q.; Ma, L.; Sun, Y.; Xiao, C. H.; Li, F.; Du, Y. P. Visualization of the electrocatalytic activity of three-dimensional MoSe2@reduced graphene oxide hybrid nanostructures for oxygen reduction reaction. Nano Res. 2016, 9, 3795–3811.

    CAS  Google Scholar 

  15. Meng, Z. H.; Chen, N.; Cai, S. C.; Wu, J. W.; Wang, R.; Tian, T.; Tang, H. L. Rational design of hierarchically porous Fe-N-doped carbon as efficient electrocatalyst for oxygen reduction reaction and Zn-air batteries. Nano Res. 2021, 14, 4768–4775.

    CAS  Google Scholar 

  16. Xia, B. Y.; Yan, Y.; Li, N.; Wu, H. B.; Lou, X. W.; Wang, X. A metal-organic framework-derived bifunctional oxygen electrocatalyst. Nat. Energy 2016, 1, 15006.

    CAS  Google Scholar 

  17. Gao, R. J.; Wang, J.; Huang, Z. F.; Zhang, R. R.; Wang, W.; Pan, L.; Zhang, J. F.; Zhu, W. K.; Zhang, X. W.; Shi, C. X. et al. Pt/Fe2O3 with Pt-Fe pair sites as a catalyst for oxygen reduction with ultralow Pt loading. Nat. Energy 2021, 6, 614–623.

    CAS  Google Scholar 

  18. Jasinski, R. A new fuel cell cathode catalyst. Nature 1964, 201, 1212–1213.

    CAS  Google Scholar 

  19. Gupta, S.; Tryk, D.; Bae, I.; Aldred, W.; Yeager, E. Heat-treated polyacrylonitrile-based catalysts for oxygen electroreduction. J. Appl. Electrochem. 1989, 19, 19–27.

    CAS  Google Scholar 

  20. Luo, E. G.; Chu, Y. Y.; Liu, J.; Shi, Z. P.; Zhu, S. Y.; Gong, L. Y.; Ge, J. J.; Choi, C. H.; Liu, C. P.; Xing, W. Pyrolyzed M-N catalysts for oxygen reduction reaction: Progress and prospects. Energy Environ. Sci. 2021, 14, 2158–2185.

    CAS  Google Scholar 

  21. Li, Z. Q.; Jiang, G. P.; Deng, Y. P.; Liu, G. H.; Ren, D. Z.; Zhang, Z.; Zhu, J. B.; Gao, R.; Jiang, Y.; Luo, D. et al. Deep-breathing honeycomb-like Co-Nx-C nanopolyhedron bifunctional oxygen electrocatalysts for rechargeable Zn-air batteries. iScience 2020, 23, 101404.

    CAS  Google Scholar 

  22. Qin, J. Y.; Liu, H.; Zou, P. C.; Zhang, R.; Wang, C. Y.; Xin, H. L. Altering ligand fields in single-atom sites through second-shell anion modulation boosts the oxygen reduction reaction. J. Am. Chem. Soc. 2022, 144, 2197–2207.

    CAS  Google Scholar 

  23. Cui, X.; Gao, L. K.; Lei, S.; Liang, S.; Zhang, J. W.; Sewell, C. D.; Xue, W. D.; Liu, Q.; Lin, Z. Q.; Yang, Y. K. Simultaneously crafting single-atomic Fe sites and graphitic layer-wrapped Fe3C nanoparticles encapsulated within mesoporous carbon tubes for oxygen reduction. Adv. Funct. Mater. 2021, 31, 2009197.

    CAS  Google Scholar 

  24. Xiao, M. L.; Zhu, J. B.; Li, G. R.; Li, N.; Li, S.; Cano, Z. P.; Ma, L.; Cui, P. X.; Xu, P.; Jiang, G. P. et al. A single-atom iridium heterogeneous catalyst in oxygen reduction reaction. Angew. Chem., Int. Ed. 2019, 58, 9640–9645.

    CAS  Google Scholar 

  25. Liu, S. W.; Li, C. Z.; Zachman, M. J.; Zeng, Y. C.; Yu, H. R.; Li, B. Y.; Wang, M. Y.; Braaten, J.; Liu, J. W.; Meyer, H. M. et al. Atomically dispersed iron sites with a nitrogen-carbon coating as highly active and durable oxygen reduction catalysts for fuel cells. Nat. Energy 2022, 7, 652–663.

    CAS  Google Scholar 

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

    CAS  Google Scholar 

  27. Zhang, Q. Q.; Guan, J. Q. Single-atom catalysts for electrocatalytic applications. Adv. Funct. Mater. 2020, 30, 2000768.

    CAS  Google Scholar 

  28. Marshall-Roth, T.; Libretto, N. J.; Wrobel, A. T.; Anderton, K. J.; Pegis, M. L.; Ricke, N. D.; Voorhis, T. V.; Miller, J. T.; Surendranath, Y. A pyridinic Fe-N4 macrocycle models the active sites in Fe/N-doped carbon electrocatalysts. Nat. Commun. 2020, 11, 5283.

    CAS  Google Scholar 

  29. Liu, K.; Fu, J. W.; Lin, Y. Y.; Luo, T.; Ni, G. H.; Li, H. M.; Lin, Z.; Liu, M. Insights into the activity of single-atom Fe-N-C catalysts for oxygen reduction reaction. Nat. Commun. 2022, 13, 2075.

    CAS  Google Scholar 

  30. Guo, D. H.; Shibuya, R.; Akiba, C.; Saji, S.; Kondo, T.; Nakamura, J. Active sites of nitrogen-doped carbon materials for oxygen reduction reaction clarified using model catalysts. Science 2016, 351, 361–365.

    CAS  Google Scholar 

  31. Chung, H. T.; Cullen, D. A.; Higgins, D.; Sneed, B. T.; Holby, E. F.; More, K. L.; Zelenay, P. Direct atomic-level insight into the active sites of a high-performance PGM-free ORR catalyst. Science 2017, 357, 479–484.

    CAS  Google Scholar 

  32. Sun, Y. L.; Wang, J.; Liu, Q.; Xia, M. R.; Tang, Y. F.; Gao, F. M.; Hou, Y. L.; Tse, J.; Zhao, Y. F. Itinerant ferromagnetic half metallic cobalt-iron couples: Promising bifunctional electrocatalysts for ORR and OER. J. Mater. Chem. A 2019, 7, 27175–27185.

    CAS  Google Scholar 

  33. Zhang, N.; Zhou, T. P.; Chen, M. L.; Feng, H.; Yuan, R. L.; Zhong, C. A.; Yan, W. S.; Tian, Y. C.; Wu, X. J.; Chu, W. S. et al. High-purity pyrrole-type FeN4 sites as a superior oxygen reduction electrocatalyst. Energy Environ. Sci. 2020, 13, 111–118.

    CAS  Google Scholar 

  34. Xie, X. H.; He, C.; Li, B. Y.; He, Y. H.; Cullen, D. A.; Wegener, E. C.; Kropf, A. J.; Martinez, U.; Cheng, Y. W.; Engelhard, M. H. et al. Performance enhancement and degradation mechanism identification of a single-atom Co-N-C catalyst for proton exchange membrane fuel cells. Nat. Catal. 2020, 3, 1044–1054.

    CAS  Google Scholar 

  35. Tian, H.; Cui, X. Z.; Dong, H. L.; Meng, G.; Kong, F. T.; Chen, Y. F.; Peng, L. X.; Chen, C.; Chang, Z. W.; Shi, J. L. Engineering single MnN4 atomic active sites on polydopamine-modified helical carbon tubes towards efficient oxygen reduction. Energy Storage Mater. 2021, 37, 274–282.

    Google Scholar 

  36. Liu, S.; Li, Z. D.; Wang, C. L.; Tao, W. W.; Huang, M. X.; Zuo, M.; Yang, Y.; Yang, K.; Zhang, L. J.; Chen, S. et al. Turning main-group element magnesium into a highly active electrocatalyst for oxygen reduction reaction. Nat. Commun. 2020, 11, 938.

    CAS  Google Scholar 

  37. Zhu, M. Z.; Zhao, C.; Liu, X. K.; Wang, X. L.; Zhou, F. Y.; Wang, J.; Hu, Y. M.; Zhao, Y. F.; Yao, T.; Yang, L. M. et al. Single atomic cerium sites with a high coordination number for efficient oxygen reduction in proton-exchange membrane fuel cells. ACS Catal. 2021, 11, 3923–3929.

    CAS  Google Scholar 

  38. Lu, Z. Y.; Wang, B.; Hu, Y. F.; Liu, W.; Zhao, Y. F.; Yang, R. O.; Li, Z. P.; Luo, J.; Chi, B.; Jiang, Z. et al. An isolated zinc-cobalt atomic pair for highly active and durable oxygen reduction. Angew. Chem., Int. Ed. 2019, 58, 2622–2626.

    CAS  Google Scholar 

  39. Chen, J. Y.; Li, H.; Fan, C.; Meng, Q. W.; Tang, Y. W.; Qiu, X. Y.; Fu, G. T.; Ma, T. Y. Dual single-atomic Ni-N4 and Fe-N4 sites constructing janus hollow graphene for selective oxygen electrocatalysis. Adv. Mater. 2020, 32, 2003134.

    CAS  Google Scholar 

  40. Li, L. F.; Wen, Y. D.; Han, G. K.; Liu, Y. X.; Song, Y. J.; Zhang, W.; Sun, J.; Du, L.; Kong, F. P.; Ma, Y. L. et al. Tailoring the stability of Fe-N-C via pyridinic nitrogen for acid oxygen reduction reaction. Chem. Eng. J. 2022, 437, 135320.

    CAS  Google Scholar 

  41. Wang, R. G.; Zhang, L. F.; Shan, J. Q.; Yang, Y. Y.; Lee, J. F.; Chen, T. Y.; Mao, J.; Zhao, Y.; Yang, L. J.; Hu, Z. P. et al. Tuning Fe spin moment in Fe-N-C catalysts to climb the activity volcano via a local geometric distortion strategy. Adv. Sci. 2022, 9, e2203917.

    Google Scholar 

  42. Haile, A. S.; Hansen, H. A.; Yohannes, W.; Mekonnen, Y. S. The role of nitrogen and sulfur dual coordination of cobalt in Co-N4−xSx/C single atom catalysts in the oxygen reduction reaction. Sustainable Energy Fuels 2022, 6, 179–187.

    CAS  Google Scholar 

  43. Li, L. B.; Huang, S. H.; Cao, R.; Yuan, K.; Lu, C. B.; Huang, B. Y.; Tang, X. N.; Hu, T.; Zhuang, X. D.; Chen, Y. W. Optimizing microenvironment of asymmetric N, S-coordinated single-atom Fe via axial fifth coordination toward efficient oxygen electroreduction. Small 2022, 18, 2105387.

    CAS  Google Scholar 

  44. Wang, X.; Jia, Y.; Mao, X.; Liu, D. B.; He, W. X.; Li, J.; Liu, J. G.; Yan, X. C.; Chen, J.; Song, L. et al. Edge-rich Fe-N4 active sites in defective carbon for oxygen reduction catalysis. Adv. Mater. 2020, 32, 2000966.

    CAS  Google Scholar 

  45. Jiang, T.; Luan, W. L.; Turyanska, L.; Feng, Q. Enhanced electrocatalytic oxygen reduction reaction for Fe-N4-C by the incorporation of Co nanoparticles. Nanoscale 2021, 13, 6521–6530.

    CAS  Google Scholar 

  46. Xia, D. S.; Yang, X.; Xie, L.; Wei, Y. P.; Jiang, W. L.; Dou, M.; Li, X. N.; Li, J.; Gan, L.; Kang, F. Y. Direct growth of carbon nanotubes doped with single atomic Fe-N4 active sites and neighboring graphitic nitrogen for efficient and stable oxygen reduction electrocatalysis. Adv. Funct. Mater. 2019, 29, 1906174.

    CAS  Google Scholar 

  47. Yang, X.; Xia, D. S.; Kang, Y. Q.; Du, H. D.; Kang, F. Y.; Gan, L.; Li, J. Unveiling the axial hydroxyl ligand on Fe-N4-C electrocatalysts and its impact on the pH-dependent oxygen reduction activities and poisoning kinetics. Adv. Sci. 2020, 7, 2000176.

    CAS  Google Scholar 

  48. Xu, H. X.; Cheng, D. J.; Cao, D. P.; Zeng, X. C. A universal principle for a rational design of single-atom electrocatalysts. Nat. Catal. 2018, 1, 339–348.

    CAS  Google Scholar 

  49. Zhao, C. X.; Li, B. Q.; Liu, J. N.; Zhang, Q. Intrinsic electrocatalytic activity regulation of M-N-C single-atom catalysts for the oxygen reduction reaction. Angew. Chem., Int. Ed. 2021, 60, 4448–4463.

    CAS  Google Scholar 

  50. Lin, Y. Y.; Liu, K.; Chen, K. J.; Xu, Y.; Li, H. M.; Hu, J. H.; Lu, Y. R.; Chan, T. S.; Qiu, X. Q.; Fu, J. W. et al. Tuning charge distribution of FeN4 via external N for enhanced oxygen reduction reaction. ACS Catal. 2021, 11, 6304–6315.

    CAS  Google Scholar 

  51. Wang, X. X.; Wang, B.; Zhong, J.; Zhao, F. P.; Han, N.; Huang, W. J.; Zeng, M.; Fan, J.; Li, Y. G. Iron polyphthalocyanine sheathed multiwalled carbon nanotubes: A high-performance electrocatalyst for oxygen reduction reaction. Nano Res. 2016, 9, 1497–1506.

    CAS  Google Scholar 

  52. Fu, X. G.; Li, N.; Ren, B. H.; Jiang, G. P.; Liu, Y. R.; Hassan, F. M.; Su, D.; Zhu, J. B.; Yang, L.; Bai, Z. Y. et al. Tailoring FeN4 sites with edge enrichment for boosted oxygen reduction performance in proton exchange membrane fuel cell. Adv. Energy Mater. 2019, 9, 1803737.

    Google Scholar 

  53. Jin, X. X.; Xie, Y.; Fu, J. H.; Zhao, C. Y.; Xu, Y. H.; Lv, Y.; Zhang, B. S.; Sun, K. J.; Si, R.; Huang, J. H. A highly efficient Fe-N-C electrocatalyst with atomically dispersed FeN4 sites for the oxygen reduction reaction. ChemCatChem 2021, 13, 2683–2690.

    CAS  Google Scholar 

  54. Qiao, M. F.; Wang, Y.; Wang, Q.; Hu, G. Z.; Mamat, X.; Zhang, S. S.; Wang, S. Y. Hierarchically ordered porous carbon with atomically dispersed FeN4 for ultraefficient oxygen reduction reaction in proton-exchange membrane fuel cells. Angew. Chem., Int. Ed. 2020, 59, 2688–2694.

    CAS  Google Scholar 

  55. Yin, H. B.; Yuan, P. F.; Lu, B. A.; Xia, H. C.; Guo, K.; Yang, G. G.; Qu, G.; Xue, D. P.; Hu, Y. F.; Cheng, J. Q. et al. Phosphorus-driven electron delocalization on edge-type FeN4 active sites for oxygen reduction in acid medium. ACS Catal. 2021, 11, 12754–12762.

    CAS  Google Scholar 

  56. Su, P. P.; Huang, W. J.; Zhang, J. W.; Guharoy, U.; Du, Q. G.; Sun, Q.; Jiang, Q. K.; Cheng, Y.; Yang, J.; Zhang, X. L. et al. Fe atoms anchored on defective nitrogen doped hollow carbon spheres as efficient electrocatalysts for oxygen reduction reaction. Nano Res. 2021, 14, 1069–1077.

    CAS  Google Scholar 

  57. Adabi, H.; Shakouri, A.; Hassan, N. U.; Varcoe, J. R.; Zulevi, B.; Serov, A.; Regalbuto, J. R.; Mustain, W. E. High-performing commercial Fe-N-C cathode electrocatalyst for anion-exchange membrane fuel cells. Nat. Energy 2021, 6, 834–843.

    CAS  Google Scholar 

  58. Wan, X.; Liu, X. F.; Li, Y. C.; Yu, R. H.; Zheng, L. R.; Yan, W. S.; Wang, H.; Xu, M.; Shui, J. L. Fe-N-C electrocatalyst with dense active sites and efficient mass transport for high-performance proton exchange membrane fuel cells. Nat. Catal. 2019, 2, 259–268.

    CAS  Google Scholar 

  59. Snitkoff-Sol, R. Z.; Friedman, A.; Honig, H. C.; Yurko, Y.; Kozhushner, A.; Zachman, M. J.; Zelenay, P.; Bond, A. M.; Elbaz, L. Quantifying the electrochemical active site density of precious metal-free catalysts in situ in fuel cells. Nat. Catal. 2022, 5, 163–170.

    CAS  Google Scholar 

  60. Jiao, L.; Li, J. K.; Richard, L. L.; Sun, Q.; Stracensky, T.; Liu, E. S.; Sougrati, M. T.; Zhao, Z. P.; Yang, F.; Zhong, S. C. et al. Chemical vapour deposition of Fe-N-C oxygen reduction catalysts with full utilization of dense Fe-N4 sites. Nat. Mater. 2021, 20, 1385–1391.

    CAS  Google Scholar 

  61. Ding, R.; Liu, Y. D.; Rui, Z. Y.; Li, J.; Liu, J. G.; Zou, Z. G. Facile grafting strategy synthesis of single-atom electrocatalyst with enhanced ORR performance. Nano Res. 2020, 13, 1519–1526.

    CAS  Google Scholar 

  62. Xiao, M. L.; Xing, Z. H.; Jin, Z.; Liu, C. P.; Ge, J. J.; Zhu, J. B.; Wang, Y.; Zhao, X.; Chen, Z. W. Preferentially engineering FeN4 edge sites onto graphitic nanosheets for highly active and durable oxygen electrocatalysis in rechargeable Zn-air batteries. Adv. Mater. 2020, 32, e2004900.

    Google Scholar 

  63. Xiao, M. L.; Zhu, J. B.; Ma, L.; Jin, Z.; Ge, J. J.; Deng, X.; Hou, Y.; He, Q. G.; Li, J. K.; Jia, Q. Y. et al. Microporous framework induced synthesis of single-atom dispersed Fe-N-C acidic ORR catalyst and its in situ reduced Fe-N4 active site identification revealed by X-ray absorption spectroscopy. ACS Catal. 2018, 8, 2824–2832.

    CAS  Google Scholar 

  64. Cai, H. Z.; Chen, B. B.; Zhang, X.; Deng, Y. C.; Xiao, D. Q.; Ma, D.; Shi, C. Highly active sites of low spin FeIIN4 species: The identification and the ORR performance. Nano Res. 2021, 14, 122–130.

    CAS  Google Scholar 

  65. Li, J. K.; Sougrati, M. T.; Zitolo, A.; Ablett, J. M.; Oğuz, I. C.; Mineva, T.; Matanovic, I.; Atanassov, P.; Huang, Y.; Zenyuk, I. et al. Identification of durable and non-durable FeN sites in Fe-N-C materials for proton exchange membrane fuel cells. Nat. Catal. 2020, 4, 10–19.

    Google Scholar 

  66. Zitolo, A.; Goellner, V.; Armel, V.; Sougrati, M. T.; Mineva, T.; Stievano, L.; Fonda, E.; Jaouen, F. Identification of catalytic sites for oxygen reduction in iron- and nitrogen-doped graphene materials. Nat. Mater. 2015, 14, 937–942.

    CAS  Google Scholar 

  67. Xu, X. L.; Zhang, X. M.; Kuang, Z. C.; Xia, Z. X.; Rykov, A. I.; Yu, S. S.; Wang, J. H.; Wang, S. L.; Sun, G. Q. Investigation on the demetallation of Fe-N-C for oxygen reduction reaction: The influence of structure and structural evolution of active site. Appl. Catal. B: Environ. 2022, 309, 121290.

    CAS  Google Scholar 

  68. Du, L.; Prabhakaran, V.; Xie, X. H.; Park, S.; Wang, Y.; Shao, Y. Y. Low-PGM and PGM-free catalysts for proton exchange membrane fuel cells: Stability challenges and material solutions. Adv. Mater. 2021, 33, e1908232.

    Google Scholar 

  69. Xie, H.; Xie, X. H.; Hu, G. X.; Prabhakaran, V.; Saha, S.; Gonzalez-Lopez, L.; Phakatkar, A. H.; Hong, M.; Wu, M. L.; Shahbazian-Yassar, R. et al. Ta-TiOx nanoparticles as radical scavengers to improve the durability of Fe-N-C oxygen reduction catalysts. Nat. Energy 2022, 7, 281–289.

    CAS  Google Scholar 

  70. Li, X. H.; Yang, X. X.; Liu, L. T.; Zhao, H.; Li, Y. W.; Zhu, H. Y.; Chen, Y. Z.; Guo, S. W.; Liu, Y. N.; Tan, Q. et al. Chemical vapor deposition for N/S-doped single fe site catalysts for the oxygen reduction in direct methanol fuel cells. ACS Catal. 2021, 11, 7450–7459.

    CAS  Google Scholar 

  71. Yu, L.; Li, Y. C.; Ruan, Y. F. Dynamic control of sacrificial bond transformation in the Fe-N-C single-atom catalyst for molecular oxygen reduction. Angew. Chem., Int. Ed. 2021, 60, 25296–25301.

    CAS  Google Scholar 

  72. Yuan, K.; Lützenkirchen-Hecht, D.; Li, L. B.; Shuai, L.; Li, Y. Z.; Cao, R.; Qiu, M.; Zhuang, X. D.; Leung, M. K. H.; Chen, Y. W. et al. Boosting oxygen reduction of single iron active sites via geometric and electronic engineering: Nitrogen and phosphorus dual coordination. J. Am. Chem. Soc. 2020, 142, 2404–2412.

    CAS  Google Scholar 

  73. Jin, Z. Y.; Li, P. P.; Meng, Y.; Fang, Z. W.; Xiao, D.; Yu, G. H. Understanding the inter-site distance effect in single-atom catalysts for oxygen electroreduction. Nat. Catal. 2021, 4, 615–622.

    CAS  Google Scholar 

  74. Li, X. L.; Xiang, Z. H. Identifying the impact of the covalent-bonded carbon matrix to FeN4 sites for acidic oxygen reduction. Nat. Commun. 2022, 13, 57.

    CAS  Google Scholar 

  75. Chen, K. J.; Liu, K.; An, P. D.; Li, H. J. W.; Lin, Y. Y.; Hu, J. H.; Jia, C. K.; Fu, J. W.; Li, H. M.; Liu, H. et al. Iron phthalocyanine with coordination induced electronic localization to boost oxygen reduction reaction. Nat. Commun. 2020, 11, 4173.

    CAS  Google Scholar 

  76. Wang, J.; Li, L. Q.; Chen, X.; Lu, Y. L.; Yang, W. S.; Duan, X. A Co-N/C hollow-sphere electrocatalyst derived from a metanilic CoAl layered double hydroxide for the oxygen reduction reaction, and its active sites in various pH media. Nano Res. 2017, 10, 2508–2518.

    CAS  Google Scholar 

  77. He, Y. H.; Shi, Q. R.; Shan, W. T.; Li, X.; Kropf, A. J.; Wegener, E. C.; Wright, J.; Karakalos, S.; Su, D.; Cullen, D. A. et al. Dynamically unveiling metal—nitrogen coordination during thermal activation to design high-efficient atomically dispersed CoN4 active sites. Angew. Chem., Int. Ed. 2021, 60, 9516–9526.

    CAS  Google Scholar 

  78. Chen, L. Y.; Liu, X. F.; Zheng, L. R.; Li, Y. C.; Guo, X.; Wan, X.; Liu, Q. T.; Shang, J. X.; Shui, J. L. Insights into the role of active site density in the fuel cell performance of Co-N-C catalysts. Appl. Catal. B: Environ 2019, 256, 117849.

    CAS  Google Scholar 

  79. Xiao, G. F.; Lu, R. H.; Liu, J. F.; Liao, X. B.; Wang, Z. Y.; Zhao, Y. Coordination environments tune the activity of oxygen catalysis on single atom catalysts: A computational study. Nano Res. 2022, 15, 3073–3081.

    CAS  Google Scholar 

  80. Mahsud, A.; Chen, J. N.; Yuan, X. L.; Lyu, F. L.; Zhong, Q. X.; Chen, J. X.; Yin, Y. D.; Zhang, Q. Self-templated formation of cobalt-embedded hollow N-doped carbon spheres for efficient oxygen reduction. Nano Res. 2021, 14, 2819–2825.

    CAS  Google Scholar 

  81. Guo, L.; Hwang, S.; Li, B. Y.; Yang, F.; Wang, M. Y.; Chen, M. J.; Yang, X. X.; Karakalos, S. G.; Cullen, D. A.; Feng, Z. X. et al. Promoting atomically dispersed MnN4 sites via sulfur doping for oxygen reduction: Unveiling intrinsic activity and degradation in fuel cells. ACS Nano 2021, 15, 6886–6899.

    CAS  Google Scholar 

  82. Li, J. Z.; Chen, M. J.; Cullen, D. A.; Hwang, S.; Wang, M. Y.; Li, B. Y.; Liu, K. X.; Karakalos, S.; Lucero, M.; Zhang, H. G. et al. Atomically dispersed manganese catalysts for oxygen reduction in proton-exchange membrane fuel cells. Nat. Catal. 2018, 1, 935–945.

    CAS  Google Scholar 

  83. Bai, L.; Duan, Z. Y.; Wen, X. D.; Si, R.; Guan, J. Q. Atomically dispersed manganese-based catalysts for efficient catalysis of oxygen reduction reaction. Appl. Catal. B: Environ. 2019, 257, 117930.

    CAS  Google Scholar 

  84. Chen, M. J.; Li, X.; Yang, F.; Li, B. Y.; Stracensky, T.; Karakalos, S.; Mukerjee, S.; Jia, Q. Y.; Su, D.; Wang, G. F. et al. Atomically dispersed MnN4 catalysts via environmentally benign aqueous synthesis for oxygen reduction: Mechanistic understanding of activity and stability improvements. ACS Catal. 2020, 10, 10523–10534.

    CAS  Google Scholar 

  85. Vashistha, V. K.; Kumar, A. Design and synthesis of MnN4 macrocyclic complex for efficient oxygen reduction reaction electrocatalysis. Inorg. Chem. Commun. 2020, 112, 107700.

    CAS  Google Scholar 

  86. Yang, Y.; Mao, K. T.; Gao, S. Q.; Huang, H.; Xia, G. L.; Lin, Z. Y.; Jiang, P.; Wang, C. L; Wang, H.; Chen, Q. W. O-, N-atoms-coordinated Mn cofactors within a graphene framework as bioinspired oxygen reduction reaction electrocatalysts. Adv. Mater. 2018, 30, 1801732.

    Google Scholar 

  87. Li, J.; Chen, S. G.; Yang, N.; Deng, M. M.; Ibraheem, S.; Deng, J. H.; Li, J.; Li, L.; Wei, Z. D. Ultrahigh-loading zinc single-atom catalyst for highly efficient oxygen reduction in both acidic and alkaline media. Angew. Chem., Int. Ed. 2019, 58, 7035–7039.

    CAS  Google Scholar 

  88. Luo, E. G.; Zhang, H.; Wang, X.; Gao, L. Q.; Gong, L. Y.; Zhao, T.; Jin, Z.; Ge, J. J.; Jiang, Z.; Liu, C. P. et al. Single-atom Cr-N4 sites designed for durable oxygen reduction catalysis in acid media. Angew. Chem., Int. Ed. 2019, 58, 12469–12475.

    CAS  Google Scholar 

  89. Hu, J. W.; Cai, X. B.; Wu, J.; Xin, C. C.; Guo, J. Y.; Liu, Z. R.; Wei, J. Z.; Cheng, X. S.; Hao, C.; Dong, H. P. et al. Boosting oxygen-reduction catalysis over mononuclear CuN2+2 moiety for rechargeable Zn-air battery. Chem. Eng. J. 2022, 430, 133105.

    CAS  Google Scholar 

  90. Lin, Z. Y.; Huang, H.; Cheng, L.; Hu, W.; Xu, P. P.; Yang, Y.; Li, J. M.; Gao, F. Y.; Yang, K.; Liu, S. et al. Tuning the p-orbital electron structure of s-block metal Ca enables a high-performance electrocatalyst for oxygen reduction. Adv. Mater. 2021, 33, 2107103.

    CAS  Google Scholar 

  91. Luo, F.; Roy, A.; Silvioli, L.; Cullen, D. A.; Zitolo, A.; Sougrati, M. T.; Oguz, I. C.; Mineva, T.; Teschner, D.; Wagner, S. et al. P-block single-metal-site tin/nitrogen-doped carbon fuel cell cathode catalyst for oxygen reduction reaction. Nat. Mater. 2020, 19, 1215–1223.

    CAS  Google Scholar 

  92. Gu, Y.; Xi, B. J.; Zhang, H.; Ma, Y. C.; Xiong, S. L. Activation of main-group antimony atomic sites for oxygen reduction catalysis. Angew. Chem., Int. Ed. 2022, 61, e202202200.

    CAS  Google Scholar 

  93. Zhang, D.; Xie, X.; Sun, P. P.; Wei, Y. A.; Gong, T.; Huang, N.; Lv, X. W.; Fang, L.; Sun, X. H. Atomically dispersed antimony on N-doped carbon for highly efficient oxygen reduction reaction. Chem. Eng. J. 2022, 439, 135700.

    CAS  Google Scholar 

  94. Hu, H.; Wang, J. J.; Cui, B. F.; Zheng, X. R.; Lin, J. G.; Deng, Y. D.; Han, X. P. Atomically dispersed selenium sites on nitrogen-doped carbon for efficient electrocatalytic oxygen reduction. Angew. Chem., Int. Ed. 2022, 61, e202114441.

    CAS  Google Scholar 

  95. Xiao, M. L.; Gao, L. Q.; Wang, Y.; Wang, X.; Zhu, J. B.; Jin, Z.; Liu, C. P.; Chen, H. Q.; Li, G. R.; Ge, J. J. et al. Engineering energy level of metal center: Ru single-atom site for efficient and durable oxygen reduction catalysis. J. Am. Chem. Soc. 2019, 141, 19800–19806.

    CAS  Google Scholar 

  96. Wang, T. Z.; Cao, X. J.; Qin, H. Y.; Shang, L.; Zheng, S. Y.; Fang, F.; Jiao, L. F. P-block atomically dispersed antimony catalyst for highly efficient oxygen reduction reaction. Angew. Chem., Int. Ed. 2021, 60, 21237–21241.

    CAS  Google Scholar 

  97. Deng, C. F.; Su, Y.; Li, F. H.; Shen, W. F.; Chen, Z. F.; Tang, Q. Understanding activity origin for the oxygen reduction reaction on bi-atom catalysts by DFT studies and machine-learning. J. Mater. Chem. A 2020, 5, 24563–24571.

    Google Scholar 

  98. Xu, J.; Lai, S. H.; Qi, D. F.; Hu, M.; Peng, X. Y.; Liu, Y. F.; Liu, W.; Hu, G. Z.; Xu, H.; Li, F. et al. Atomic Fe-Zn dual-metal sites for high-efficiency pH-universal oxygen reduction catalysis. Nano Res. 2021, 14, 1374–1381.

    CAS  Google Scholar 

  99. Xiao, M. L.; Zhang, H.; Chen, Y. T.; Zhu, J. B.; Gao, L. Q.; Jin, Z.; Ge, J. J.; Jiang, Z.; Chen, S. L.; Liu, C. P. et al. Identification of binuclear Co2N5 active sites for oxygen reduction reaction with more than one magnitude higher activity than single atom CoN4 site. Nano Energy 2018, 46, 396–403.

    CAS  Google Scholar 

  100. Xiao, M. L.; Zhu, J. B.; Li, S.; Li, G. R.; Liu, W. W.; Deng, Y. P.; Bai, Z. Y.; Ma, L.; Feng, M.; Wu, T. P. et al. 3d-Orbital occupancy regulated Ir-Co atomic pair toward superior bifunctional oxygen electrocatalysis. ACS Catal. 2021, 11, 8837–8846.

    CAS  Google Scholar 

  101. Xiao, M. L.; Chen, Y. T.; Zhu, J. B.; Zhang, H.; Zhao, X.; Gao, L. Q.; Wang, X.; Zhao, J.; Ge, J. J.; Jiang, Z. et al. Climbing the apex of the ORR volcano plot via binuclear site construction: Electronic and geometric engineering. J. Am. Chem. Soc. 2019, 141, 17763–17770.

    CAS  Google Scholar 

  102. Li, L.; Li, Y. M.; Huang, R.; Cao, X. R.; Wen, Y. H. Boosting the electrocatalytic activity of Fe-Co dual-atom catalysts for oxygen reduction reaction by ligand-modification engineering. ChemCatChem 2021, 13, 4645–4651.

    CAS  Google Scholar 

  103. Zhou, Y. D.; Yang, W.; Utetiwabo, W.; Lian, Y. M.; Yin, X.; Zhou, L.; Yu, P. W.; Chen, R. J.; Sun, S. R. Revealing of active sites and catalytic mechanism in N-coordinated Fe, Ni dual-doped carbon with superior acidic oxygen reduction than single-atom catalyst. J. Phys. Chem. Lett. 2020, 11, 1404–1410.

    CAS  Google Scholar 

  104. Yang, G. G.; Zhu, J. W.; Yuan, P. F.; Hu, Y. F.; Qu, G.; Lu, B. A.; Xue, X. Y.; Yin, H. B.; Cheng, W. Z.; Cheng, J. Q. et al. Regulating Fe-spin state by atomically dispersed Mn-N in Fe-N-C catalysts with high oxygen reduction activity. Nat. Commun. 2021, 12, 1734.

    CAS  Google Scholar 

  105. Zhang, N.; Zhou, T. P.; Ge, J. K.; Lin, Y.; Du, Z. Y.; Zhong, C. A.; Wang, W. J.; Jiao, Q. Y.; Yuan, R. L.; Tian, Y. C. et al. High-density planar-like Fe2N6 structure catalyzes efficient oxygen reduction. Matter 2020, 3, 509–521.

    Google Scholar 

  106. Cui, T. T.; Wang, Y. P.; Ye, T.; Wu, J.; Chen, Z. Q.; Li, J.; Lei, Y. P.; Wang, D. S.; Li, Y. D. Engineering dual single-atom sites on 2D ultrathin N-doped carbon nanosheets attaining ultra-low-temperature zinc-air battery. Angew. Chem., Int. Ed. 2022, 61, e202115219.

    CAS  Google Scholar 

  107. Li, W. H.; Yang, J. R.; Wang, D. S. Long-range interactions in diatomic catalysts boosting electrocatalysis. Angew. Chem., Int. Ed. 2022, 61, e202213318.

    CAS  Google Scholar 

  108. Han, A. L.; Wang, X. J.; Tang, K.; Zhang, Z. D.; Ye, C. L.; Kong, K. J.; Hu, H. B.; Zheng, L. R.; Jiang, P.; Zhao, C. X. et al. An adjacent atomic platinum site enables single-atom iron with high oxygen reduction reaction performance. Angew. Chem., Int. Ed. 2021, 60, 19262–19271.

    CAS  Google Scholar 

  109. Fang, X. Z.; Jiao, L.; Yu, S. H.; Jiang, H. L. Metal-organic framework-derived feco-n-doped hollow porous carbon nanocubes for electrocatalysis in acidic and alkaline media. ChemSusChem 2017, 10, 3019–3024.

    CAS  Google Scholar 

  110. Liu, M.; Li, N.; Cao, S. F.; Wang, X. M.; Lu, X. Q.; Kong, L. J.; Xu, Y. H.; Bu, X. H. A “pre-constrained metal twins” strategy to prepare efficient dual-metal-atom catalysts for cooperative oxygen electrocatalysis. Adv. Mater. 2022, 34, e2107421.

    Google Scholar 

  111. Zhu, Z. J.; Yin, H. J.; Wang, Y.; Chuang, C. H.; Xing, L.; Dong, M. Y.; Lu, Y. R.; Casillas-Garcia, G.; Zheng, Y. L.; Chen, S. et al. Coexisting single-atomic fe and Ni sites on hierarchically ordered porous carbon as a highly efficient ORR electrocatalyst. Adv. Mater. 2020, 32, e2004670.

    Google Scholar 

  112. Luo, F.; Zhu, J. B.; Ma, S. X.; Li, M.; Xu, R. Z.; Zhang, Q.; Yang, Z. H.; Qu, K. G.; Cai, W. W.; Chen, Z. W. Regulated coordination environment of Ni single atom catalyst toward high-efficiency oxygen electrocatalysis for rechargeable Zinc-air batteries. Energy Storage Mater. 2021, 35, 723–730.

    Google Scholar 

  113. Cai, H. Z.; Zhang, G. H.; Zhang, X.; Chen, B. B.; Lu, Z.; Xu, H. J.; Gao, R.; Shi, C. Engineering the local coordination environment and density of FeN4 sites by mn cooperation for electrocatalytic oxygen reduction. Small 2022, 18, e2200911.

    Google Scholar 

  114. Tong, M. M.; Sun, F. F.; Xie, Y.; Wang, Y.; Yang, Y. Q.; Tian, C. G.; Wang, L.; Fu, H. G. Operando cooperated catalytic mechanism of atomically dispersed Cu-N4 and Zn-N4 for promoting oxygen reduction reaction. Angew. Chem., Int. Ed. 2021, 60, 14005–14012.

    CAS  Google Scholar 

  115. Sui, R.; Zhang, X. J.; Wang, X. D.; Wang, X. Y.; Pei, J. J.; Zhang, Y. F.; Liu, X. R.; Chen, W. X.; Zhu, W.; Zhuang, Z. B. Silver based single atom catalyst with heteroatom coordination environment as high performance oxygen reduction reaction catalyst. Nano Res. 2022, 15, 7968–7975.

    CAS  Google Scholar 

  116. Wei, X.; Zheng, D.; Zhao, M.; Chen, H. Z.; Fan, X.; Gao, B.; Gu, L.; Guo, Y.; Qin, J. B.; Wei, J. et al. Cross-linked polyphosphazene hollow nanosphere-derived N/P-doped porous carbon with single nonprecious metal atoms for the oxygen reduction reaction. Angew. Chem., Int. Ed. 2020, 59, 14639–14646.

    CAS  Google Scholar 

  117. Saputro, A. G.; Kasai, H.; Asazawa, K.; Kishi, H.; Tanaka, H. Comparative study on the catalytic activity of the TM-N2 active sites (TM = Mn, Fe, Co, Ni) in the oxygen reduction reaction: Density functional theory study. J. Phys. Soc. Japan 2013, 82, 114704.

    Google Scholar 

  118. Cai, Z. H.; Lin, S. X.; Xiao, J. J.; Muhmood, T.; Chen, Y. H.; Wang, Y. F.; Hu, X. B.; Zheng, L. R. Efficient bifunctional catalytic electrodes with uniformly distributed NiN2 active sites and channels for long-lasting rechargeable zinc-air batteries. Small 2020, 16, e2002518.

    Google Scholar 

  119. Zhang, M. T.; Li, H.; Chen, J. X.; Ma, F. X.; Zhen, L.; Wen, Z. H.; Xu, C. Y. Transition metal (Co, Ni, Fe, Cu) single-atom catalysts anchored on 3D nitrogen-doped porous carbon nanosheets as efficient oxygen reduction electrocatalysts for Zn-air battery. Small 2022, 18, e2202476.

    Google Scholar 

  120. Sun, X. X.; Li, K.; Yin, C.; Wang, Y.; He, F.; Tang, H.; Wu, Z. J. CoN3 embedded graphene, a potential catalyst for the oxygen reduction reaction from a theoretical perspective. Phys. Chem. Chem. Phys. 2017, 19, 17670–17676.

    CAS  Google Scholar 

  121. Lai, S. J.; Xu, L.; Liu, H. L.; Chen, S.; Cai, R. S.; Zhang, L. J.; Theis, W.; Sun, J.; Yang, D. J.; Zhao, X. L. Controllable synthesis of CoN3 catalysts derived from Co/Zn-ZIF-67 for electrocatalytic oxygen reduction in acidic electrolytes. J. Mater. Chem. A 2019, 7, 21884–21891.

    CAS  Google Scholar 

  122. Mohammadi-Rad, N.; Esrafili, M. D.; Sardroodi, J. J. CuN3 doped graphene as an active electrocatalyst for oxygen reduction reaction in fuel cells: A DFT study. J. Mol. Graph. Model. 2020, 96, 107537.

    CAS  Google Scholar 

  123. Li, Y. C.; Liu, X. F.; Zheng, L. R.; Shang, J. X.; Wan, X.; Hu, R. M.; Guo, X.; Hong, S.; Shui, J. L. Preparation of Fe-N-C catalysts with FeNx (x = 1, 3, 4) active sites and comparison of their activities for the oxygen reduction reaction and performances in proton exchange membrane fuel cells. J. Mater. Chem. A 2019, 7, 26147–26153.

    CAS  Google Scholar 

  124. Han, Y. L.; Li, Q. K.; Ye, K.; Luo, Y.; Jiang, J.; Zhang, G. Z. Impact of active site density on oxygen reduction reactions using monodispersed Fe-N-C single-atom catalysts. ACS Appl. Mater. Interfaces 2020, 12, 15271–15278.

    CAS  Google Scholar 

  125. Liang, X.; Li, Z. Y.; Xiao, H.; Zhang, T. F.; Xu, P.; Zhang, H.; Gao, Q. M.; Zheng, L. R. Two types of single-atom FeN4 and FeN5 electrocatalytic active centers on n-doped carbon driving high performance of the SA-Fe-NC oxygen reduction reaction catalyst. Chem. Mater. 2021, 33, 5542–5554.

    CAS  Google Scholar 

  126. Zhang, H. N.; Jia, S. P.; Shi, X. L.; Li, Z. Y.; Liu, B.; Li, N.; Li, Y.; Hu, S. L.; Wang, H. Q. Atomic Fe-N5 catalytic sites embedded in N-doped carbon as a highly efficient oxygen electrocatalyst for zinc-air batteries. Mater. Chem. Front. 2021, 5, 8127–8137.

    CAS  Google Scholar 

  127. Huang, J. S.; Lu, Q. Q.; Ma, X.; Yang, X. R. Bio-inspired FeN5 moieties anchored on a three-dimensional graphene aerogel to improve oxygen reduction catalytic performance. J. Mater. Chem. A 2018, 6, 18488–18497.

    CAS  Google Scholar 

  128. Li, L.; Chen, Y. J.; Xing, H. R.; Li, N.; Xia, J. W.; Qian, X. Y.; Xu, H.; Li, W. Z.; Yin, F. X.; He, G. Y. et al. Single-atom Fe-N5 catalyst for high-performance zinc-air batteries. Nano Res. 2022, 15, 8056–8064.

    CAS  Google Scholar 

  129. Zhu, Y. S.; Zhang, B. S.; Liu, X.; Wang, D. W.; Su, D. S. Unravelling the structure of electrocatalytically active Fe-N complexes in carbon for the oxygen reduction reaction. Angew. Chem., Int. Ed. 2014, 53, 10673–10677.

    CAS  Google Scholar 

  130. Yang, L.; Cheng, D. J.; Xu, H. X.; Zeng, X. F.; Wan, X.; Shui, J. L.; Xiang, Z. H.; Cao, D. P. Unveiling the high-activity origin of single-atom iron catalysts for oxygen reduction reaction. Proc. Natl. Acad. Sci. USA 2018, 115, 6626–6631.

    CAS  Google Scholar 

  131. Liu, K. X.; Wu, G.; Wang, G. F. Role of local carbon structure surrounding FeN4 sites in boosting the catalytic activity for oxygen reduction. J. Phys. Chem. C 2017, 121, 11319–11324.

    CAS  Google Scholar 

  132. Ha, Y.; Fei, B.; Yan, X. X.; Xu, H. B.; Chen, Z. L.; Shi, L. X.; Fu, M. S.; Xu, W.; Wu, R. B. Atomically dispersed Co-pyridinic N-C for superior oxygen reduction reaction. Adv. Energy Mater. 2020, 10, 2002592.

    CAS  Google Scholar 

  133. Zhang, J.; Yang, J. Y.; Wang, Y.; Lu, H. Q.; Zhang, M. G. Catalytic mechanism of oxygen reduction on two types of CoN4-graphene: A density functional study. Int. J. Energy Res. 2021, 45, 10858–10868.

    CAS  Google Scholar 

  134. Chen, Y. J.; Gao, R.; Ji, S. F.; Li, H. J.; Tang, K.; Jiang, P.; Hu, H. B.; Zhang, Z. D.; Hao, H. G.; Qu, Q. Y. et al. Atomic-level modulation of electronic density at cobalt single-atom sites derived from metal-organic frameworks: Enhanced oxygen reduction performance. Angew. Chem., Int. Ed. 2021, 60, 3212–3221.

    CAS  Google Scholar 

  135. Hu, B. T.; Huang, A. J.; Zhang, X. J.; Chen, Z.; Tu, R. Y.; Zhu, W.; Zhuang, Z. B.; Chen, C.; Peng, Q.; Li, Y. D. Atomic Co/Ni dual sites with N/P-coordination as bifunctional oxygen electrocatalyst for rechargeable zinc-air batteries. Nano Res. 2021, 14, 3482–3488.

    CAS  Google Scholar 

  136. Wang, J.; Li, H. G.; Liu, S. H.; Hu, Y. F.; Zhang, J.; Xia, M. R.; Hou, Y. L.; Tse, J.; Zhang, J. J.; Zhao, Y. F. Turning on Zn 4s electrons in a N2-Zn-B2 configuration to stimulate remarkable ORR performance. Angew. Chem., Int. Ed. 2021, 60, 181–185.

    CAS  Google Scholar 

  137. Zhang, H.; Sun, Q. D.; He, Q.; Zhang, Y.; He, X. H.; Gan, T.; Ji, H. B. Single Cu atom dispersed on S, N-codoped nanocarbon derived from shrimp shells for highly-efficient oxygen reduction reaction. Nano Res. 2022, 15, 5995–6000.

    CAS  Google Scholar 

  138. Zhi, Q. J.; Jiang, R.; Liu, W. P.; Sun, T. T.; Wang, K.; Jiang, J. Z. Atomic CoN3S1 sites for boosting oxygen reduction reaction via an atomic exchange strategy. Nano Res. 2022, 15, 1803–1808.

    CAS  Google Scholar 

  139. Zhuang, Z. C.; Xia, L. X.; Huang, J. Z.; Zhu, P.; Li, Y.; Ye, C. L.; Xia, M. G.; Yu, R. H.; Lang, Z. Q.; Zhu, J. X. et al. Continuous modulation of electrocatalytic oxygen reduction activities of single-atom catalysts through p-n junction rectification. Angew. Chem., Int. Ed. 2023, 135, e202212335.

    Google Scholar 

  140. Zhou, X. Y.; Xu, C.; Guo, P. P.; Sun, W. L.; Wei, P. J.; Liu, J. G. Axial ligand coordination tuning of the electrocatalytic activity of iron porphyrin electrografted onto carbon nanotubes for the oxygen reduction reaction. Chem. —Eur. J. 2021, 27, 9898–9904.

    CAS  Google Scholar 

  141. Zhang, W. L.; Meeus, E. J.; Wang, L.; Zhang, L. H.; Yang, S. C.; de Bruin, B.; Reek, J. N. H.; Yu, F. S. Boosting electrochemical oxygen reduction performance of iron phthalocyanine through axial coordination sphere interaction. ChemSusChem 2022, 15, e202102379.

    CAS  Google Scholar 

  142. Zhao, K. M.; Liu, S. Q.; Li, Y. Y.; Wei, X. L.; Ye, G. Y.; Zhu, W. W.; Su, Y. K.; Wang, J.; Liu, H. T.; He, Z. et al. Insight into the mechanism of axial ligands regulating the catalytic activity of Fe-N4 sites for oxygen reduction reaction. Adv. Energy Mater. 2022, 12, 2103588.

    CAS  Google Scholar 

  143. Liu, Y. R.; Liu, X. J.; Lv, Z. H.; Liu, R.; Li, L. H.; Wang, J. M.; Yang, W. X.; Jiang, X.; Feng, X.; Wang, B. Tuning the spin state of the iron center by bridge-bonded Fe-O-Ti ligands for enhanced oxygen reduction. Angew. Chem., Int. Ed. 2022, 134, e202117617.

    Google Scholar 

  144. Chen, C.; Yang, X. D.; Zhou, Z. Y.; Lai, Y. J.; Rauf, M.; Wang, Y.; Pan, J.; Zhuang, L.; Wang, Q.; Wang, Y. C. et al. Aminothiazole-derived N, S, Fe-doped graphene nanosheets as high performance electrocatalysts for oxygen reduction. Chem. Commun. 2015, 51, 17092–17095.

    CAS  Google Scholar 

  145. Chen, P. Z.; Zhou, T. P.; Xing, L. L.; Xu, K.; Tong, Y.; Xie, H.; Zhang, L. D.; Yan, W. S.; Chu, W. S.; Wu, C. Z. et al. Atomically dispersed iron-nitrogen species as electrocatalysts for bifunctional oxygen evolution and reduction reactions. Angew. Chem., Int. Ed. 2017, 56, 610–614.

    CAS  Google Scholar 

  146. Kwak, D. H.; Han, S. B.; Lee, Y. W.; Park, H. S.; Choi, I. A.; Ma, K. B.; Kim, M. C.; Kim, S. J.; Kim, D. H.; Sohn, J. I. et al. Fe/N/S-doped mesoporous carbon nanostructures as electrocatalysts for oxygen reduction reaction in acid medium. Appl. Catal. B: Environ. 2017, 203, 889–898.

    CAS  Google Scholar 

  147. Li, Y. H.; Chen, B. X.; Duan, X. Z.; Chen, S. M.; Liu, D. B.; Zang, K. T.; Si, R.; Lou, F. L.; Wang, X. H.; Rønning, M. et al. Atomically dispersed Fe-N-P-C complex electrocatalysts for superior oxygen reduction. Appl. Catal. B: Environ. 2019, 249, 306–315.

    CAS  Google Scholar 

  148. Liu, S. Y.; Yang, H. T.; Yao, L.; Peng, H. L.; Huang, P. R.; Lin, X. C.; Liu, L. H.; Zhang, H. Z.; Cai, P.; Wen, X. et al. Design of Fe and Cu bimetallic integration on N and F co-doped porous carbon material for oxygen reduction reaction. Int. J. Hydrogen Energy 2022, 47, 7751–7760.

    CAS  Google Scholar 

  149. Fu, S. F.; Zhu, C. Z.; Song, J. H.; Engelhard, M. H.; Li, X. L.; Zhang, P. N.; Xia, H. B.; Du, D.; Lin, Y. H. Template-directed synthesis of nitrogen- and sulfur-codoped carbon nanowire aerogels with enhanced electrocatalytic performance for oxygen reduction. Nano Res. 2017, 10, 1888–1895.

    CAS  Google Scholar 

  150. Yang, L. P.; Zhang, X.; Yu, L. X.; Hou, J. H.; Zhou, Z.; Lv, R. T. Atomic Fe-N4/C in flexible carbon fiber membrane as binder-free air cathode for Zn-air batteries with stable cycling over 1000 h. Adv. Mater. 2022, 34, e2105410.

    Google Scholar 

  151. Chen, Z. Y.; Niu, H.; Ding, J.; Liu, H.; Chen, P. H.; Lu, Y. H.; Lu, Y. R.; Zuo, W. B.; Han, L.; Guo, Y. Z. et al. Unraveling the origin of sulfur-doped Fe-N-C single-atom catalyst for enhanced oxygen reduction activity: Effect of iron spin-state tuning. Angew. Chem., Int. Ed. 2021, 60, 25404–25410.

    CAS  Google Scholar 

  152. Mun, Y.; Lee, S.; Kim, K.; Kim, S.; Lee, S.; Han, J. W.; Lee, J. Versatile strategy for tuning ORR activity of a single Fe-N4 site by controlling electron-withdrawing/donating properties of a carbon plane. J. Am. Chem. Soc. 2019, 141, 6254–6262.

    CAS  Google Scholar 

  153. Shen, H. J.; Gracia-Espino, E.; Ma, J. Y.; Zang, K. T.; Luo, J.; Wang, L.; Gao, S. S.; Mamat, X.; Hu, G. Z.; Wagberg, T. et al. Synergistic effects between atomically dispersed Fe-N-C and C-S-C for the oxygen reduction reaction in acidic media. Angew. Chem., Int. Ed. 2017, 56, 13800–13804.

    CAS  Google Scholar 

  154. Jin, H. H.; Zhou, H.; Li, W. Q.; Wang, Z. H.; Yang, J. L.; Xiong, Y. L.; He, D. P.; Chen, L.; Mu, S. C. In situ derived Fe/N/S-codoped carbon nanotubes from ZIF-8 crystals as efficient electrocatalysts for the oxygen reduction reaction and zinc-air batteries. J. Mater. Chem. A 2018, 6, 20093–20099.

    CAS  Google Scholar 

  155. Wang, J.; Wang, Q. J.; She, W. X.; Xie, C. Y.; Zhang, X. Y.; Sun, M. C.; Xiao, J. W.; Wang, S. Tuning the electron density distribution of the Co-N-C catalysts through guest molecules and heteroatom doping to boost oxygen reduction activity. J. Power Sources 2019, 418, 50–60.

    Google Scholar 

  156. Jin, H. H.; Zhou, H.; Ji, P. X.; Zhang, C. T.; Luo, J. H.; Zeng, W. H.; Hu, C. X.; He, D. P.; Mu, S. C. ZIF-8/LiFePO4 derived Fe-N-P Co-doped carbon nanotube encapsulated Fe2P nanoparticles for efficient oxygen reduction and Zn-air batteries. Nano Res 2020, 13, 818–823.

    CAS  Google Scholar 

  157. Li, J. C.; Zhong, H.; Xu, M. J.; Li, T.; Wang, L. G.; Shi, Q. R.; Feng, S.; Lyu, Z. Y.; Liu, D.; Du, D. et al. Boosting the activity of Fe-Nx moieties in Fe-N-C electrocatalysts via phosphorus doping for oxygen reduction reaction. Sci. China Mater. 2020, 63, 965–971.

    CAS  Google Scholar 

  158. Sun, H.; Liu, S. S.; Wang, M. F.; Qian, T.; Xiong, J.; Yan, C. L. Updating the intrinsic activity of a single-atom site with a P-O bond for a rechargeable Zn-air battery. ACS Appl. Mater. Interfaces 2019, 11, 33054–33061.

    CAS  Google Scholar 

  159. Diao, Y. X.; Liu, H. M.; Yao, Z. X.; Liu, Y. S.; Hu, G. X.; Zhang, Q. F.; Li, Z. Tri-(Fe/F/N)-doped porous carbons as electrocatalysts for the oxygen reduction reaction in both alkaline and acidic media. Nanoscale 2020, 12, 18826–18833.

    CAS  Google Scholar 

  160. Lee, Y. G.; Ahn, H. J. Tri(Fe/N/F)-doped mesoporous carbons as efficient electrocatalysts for the oxygen reduction reaction. Appl. Surf. Sci. 2019, 487, 389–397.

    CAS  Google Scholar 

  161. Tao, X. F.; Lu, R. H.; Ni, L. M.; Gridin, V.; Al-Hilfi, S. H.; Qiu, Z. J.; Zhao, Y.; Kramm, U. I.; Zhou, Y. Z.; Mullen, K. Facilitating the acidic oxygen reduction of Fe-N-C catalysts by fluorine-doping. Mater. Horiz. 2022, 9, 417–424.

    CAS  Google Scholar 

  162. Zhao, Y. M.; Liao, L. M.; Yu, G. Q.; Wei, P. J.; Liu, J. G. B-doped Fe/N/C porous catalyst for high-performance oxygen reduction in anion-exchange membrane fuel cells. ChemElectroChem 2019, 6, 1754–1760.

    CAS  Google Scholar 

  163. Zhao, X.; Li, X.; Bi, Z. H.; Wang, Y. W.; Zhang, H. B.; Zhou, X. H.; Wang, Q.; Zhou, Y. T.; Wang, H. S.; Hu, G. Z. Boron modulating electronic structure of FeN4C to initiate high-efficiency oxygen reduction reaction and high-performance zinc-air battery. J. Energy Chem. 2022, 66, 514–524.

    CAS  Google Scholar 

  164. Sun, H.; Wang, M. F.; Du, X. C.; Jiao, Y.; Liu, S. S.; Qian, T.; Yan, Y. C.; Liu, C.; Liao, M.; Zhang, Q. H. et al. Modulating the d-band center of boron doped single-atom sites to boost the oxygen reduction reaction. J. Mater. Chem. A 2019, 7, 20952–20957.

    CAS  Google Scholar 

  165. Zhang, W.; Mao, K. K.; Zeng, X. C. B-doped MnN4-G nanosheets as bifunctional electrocatalysts for both oxygen reduction and oxygen evolution reactions. ACS Sustainable Chem. Eng. 2019, 7, 18711–18717.

    CAS  Google Scholar 

  166. Yuan, K.; Sfaelou, S.; Qiu, M.; Lützenkirchen-Hecht, D.; Zhuang, X. D.; Chen, Y. W.; Yuan, C.; Feng, X. L.; Scherf, U. Synergetic contribution of Boron and Fe-Nx species in porous carbons toward efficient electrocatalysts for oxygen reduction reaction. ACS Energy Lett. 2018, 3, 252–260.

    CAS  Google Scholar 

  167. Chen, Z. Y.; Su, X. Z.; Ding, J.; Yang, N.; Zuo, W. B.; He, Q. Y.; Wei, Z. M.; Zhang, Q.; Huang, J.; Zhai, Y. M. Boosting oxygen reduction reaction with Fe and Se dual-atom sites supported by nitrogen-doped porous carbon. Appl. Catal. B: Environ. 2022, 308, 121206.

    CAS  Google Scholar 

  168. Ni, W. P.; Gao, Y.; Zhang, Y.; Younus, H. A.; Guo, X. G.; Ma, C.; Zhang, Y.; Duan, J. F.; Zhang, J. H.; Zhang, S. G. O-doping boosts the electrochemical oxygen reduction activity of a single fe site in hydrophilic carbon with deep mesopores. ACS Appl. Mater. Interfaces 2019, 11, 45825–45831.

    CAS  Google Scholar 

  169. Chen, Y. J.; Ji, S. F.; Zhao, S.; Chen, W. X.; Dong, J. C.; Cheong, W. C.; Shen, R. A.; Wen, X. D.; Zheng, L. R.; Rykov, A. I. et al. Enhanced oxygen reduction with single-atomic-site iron catalysts for a zinc-air battery and hydrogen-air fuel cell. Nat. Commun. 2018, 9, 5422.

    CAS  Google Scholar 

  170. Han, Y. H.; Wang, Y. G.; Xu, R. R.; Chen, W. X.; Zheng, L. R.; Han, A. J.; Zhu, Y. Q.; Zhang, J.; Zhang, H. B.; Luo, J. et al. Electronic structure engineering to boost oxygen reduction activity by controlling the coordination of the central metal. Energy Environ. Sci. 2018, 11, 2348–2352.

    CAS  Google Scholar 

  171. Zhang, E. H.; Tao, L.; An, J. K.; Zhang, J. W.; Meng, L. Z.; Zheng, X. B.; Wang, Y.; Li, N.; Du, S. X.; Zhang, J. T. et al. Engineering the local atomic environments of indium single-atom catalysts for efficient electrochemical production of hydrogen peroxide. Angew. Chem., Int. Ed. 2022, 61, e202117347.

    CAS  Google Scholar 

  172. Zong, L. B.; Fan, K. C.; Wu, W. C.; Cui, L. X.; Zhang, L. L.; Johannessen, B.; Qi, D. C.; Yin, H. J.; Wang, Y.; Liu, P. R. et al. Anchoring single copper atoms to microporous carbon spheres as high-performance electrocatalyst for oxygen reduction reaction. Adv. Funct. Mater. 2021, 31, 2104864.

    CAS  Google Scholar 

  173. Jiang, R.; Li, L.; Sheng, T.; Hu, G. F.; Chen, Y. G.; Wang, L. Y. Edge-site engineering of atomically dispersed Fe-N4 by selective C-N bond cleavage for enhanced oxygen reduction reaction activities. J. Am. Chem. Soc. 2018, 140, 11594–11598.

    CAS  Google Scholar 

  174. Yuan, S.; Zhang, J. W.; Hu, L. Y.; Li, J. N.; Li, S. W.; Gao, Y. N.; Zhang, Q. H.; Gu, L.; Yang, W. X.; Feng, X. et al. Decarboxylation-induced defects in MOF-derived single cobalt atom@carbon electrocatalysts for efficient oxygen reduction. Angew. Chem., Int. Ed. 2021, 60, 21685–21690.

    CAS  Google Scholar 

  175. Ma, L. G.; Li, J. L.; Zhang, Z. W.; Yang, H.; Mu, X. Q.; Gu, X. Y.; Jin, H. H.; Chen, D.; Yan, S. L.; Liu, S. L. et al. Atomically dispersed dual Fe centers on nitrogen-doped bamboo-like carbon nanotubes for efficient oxygen reduction. Nano Res. 2022, 15, 1966–1972.

    CAS  Google Scholar 

  176. Liu, X.; Liu, H.; Chen, C.; Zou, L. L.; Li, Y.; Zhang, Q.; Yang, B.; Zou, Z. Q.; Yang, H. Fe2N nanoparticles boosting FeNx moieties for highly efficient oxygen reduction reaction in Fe-N-C porous catalyst. Nano Res. 2019, 12, 1651–1657.

    CAS  Google Scholar 

  177. Wan, X.; Liu, Q. T.; Liu, J. Y.; Liu, S. Y.; Liu, X. F.; Zheng, L. R.; Shang, J. X.; Yu, R. H.; Shui, J. L. Iron atom-cluster interactions increase activity and improve durability in Fe-N-C fuel cells. Nat. Commun. 2022, 13, 2963.

    CAS  Google Scholar 

  178. Zheng, H. Z.; Ma, F.; Yang, H. C.; Wu, X. G.; Wang, R.; Jia, D. L.; Wang, Z. X.; Lu, N. D.; Ran, F.; Peng, S. L. Mn, N co-doped Co nanoparticles/porous carbon as air cathode for highly efficient rechargeable Zn-air batteries. Nano Res. 2022, 15, 1942–1948.

    CAS  Google Scholar 

  179. Pan, Y.; Li, M.; Mi, W. L.; Wang, M. M.; Li, J. X.; Zhao, Y. L.; Ma, X. L.; Wang, B.; Zhu, W.; Cui, Z. M. et al. Single-atomic Mn sites coupled with Fe3C nanoparticles encapsulated in carbon matrixes derived from bimetallic Mn/Fe polyphthalocyanine conjugated polymer networks for accelerating electrocatalytic oxygen reduction. Nano Res. 2022, 15, 7976–7985.

    CAS  Google Scholar 

  180. Cheng, Q. Q.; Han, S. B.; Mao, K.; Chen, C.; Yang, L. J.; Zou, Z. Q.; Gu, M.; Hu, Z.; Yang, H. Co nanoparticle embedded in atomically-dispersed Co-N-C nanofibers for oxygen reduction with high activity and remarkable durability. Nano Energy 2018, 52, 485–493.

    CAS  Google Scholar 

  181. Wang, Z.; Zhu, C.; Tan, H.; Liu, J.; Xu, L. L.; Zhang, Y. Q.; Liu, Y. P.; Zou, X. X.; Liu, Z.; Lu, X. H. Understanding the synergistic effects of cobalt single atoms and small nanoparticles: Enhancing oxygen reduction reaction catalytic activity and stability for zinc-air batteries. Adv. Funct. Mater. 2021, 31, 2104735.

    CAS  Google Scholar 

  182. Ao, X.; Zhang, W.; Li, Z. S.; Li, J. G.; Soule, L.; Huang, X.; Chiang, W. H.; Chen, H. M.; Wang, C. D.; Liu, M. L. et al. Markedly enhanced oxygen reduction activity of single-atom Fe catalysts via integration with Fe nanoclusters. ACS Nano 2019, 13, 11853–11862.

    CAS  Google Scholar 

  183. Huang, H. J.; Yu, D. S.; Hu, F.; Huang, S. C.; Song, J. N.; Chen, H. Y.; Li, L. L.; Peng, S. J. Clusters induced electron redistribution to tune oxygen reduction activity of transition metal single-atom for metal-air batteries. Angew. Chem., Int. Ed. 2022, 61, e202116068.

    CAS  Google Scholar 

  184. Sun, X. P.; Wei, P.; Gu, S. Q.; Zhang, J. X.; Jiang, Z.; Wan, J.; Chen, Z. Y.; Huang, L.; Xu, Y.; Fang, C. et al. Atomic-level Fe-N-C coupled with Fe3C-Fe nanocomposites in carbon matrixes as high-efficiency bifunctional oxygen catalysts. Small 2020, 16, e1906057.

    Google Scholar 

  185. Cheng, X. Y.; Yang, J.; Yan, W.; Han, Y.; Qu, X. M.; Yin, S. H.; Chen, C.; Ji, R. Y.; Li, Y. R.; Li, G. et al. Nano-geometric deformation and synergistic Co nanoparticles Co-N4 composite sites for proton exchange membrane fuel cells. Energy Environ. Sci. 2021, 14, 5958–5967.

    CAS  Google Scholar 

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Acknowledgements

This work was supported by the National Natural Science Foundation of China (No. 22272161).

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Authors and Affiliations

  1. State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, China

    Li Zhang, Qinglei Meng, Ruixue Zheng, Liuqing Wang, Wei Xing & Meiling Xiao

  2. Sustainable Energy Laboratory, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan, 430074, China

    Li Zhang & Weiwei Cai

  3. School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei, 230026, China

    Ruixue Zheng, Liuqing Wang, Wei Xing & Meiling Xiao

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  1. Li Zhang
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  2. Qinglei Meng
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  3. Ruixue Zheng
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  4. Liuqing Wang
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  5. Wei Xing
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Correspondence to Wei Xing, Weiwei Cai or Meiling Xiao.

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Zhang, L., Meng, Q., Zheng, R. et al. Microenvironment regulation of M-N-C single-atom catalysts towards oxygen reduction reaction. Nano Res. 16, 4468–4487 (2023). https://doi.org/10.1007/s12274-023-5457-9

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  • DOI: https://doi.org/10.1007/s12274-023-5457-9

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