Phosphorus-doping activates carbon nanotubes for efficient electroreduction of nitrogen to ammonia


The electrochemical nitrogen reduction reaction (NRR) as an energy-efficient approach for ammonia synthesis is hampered by the low ammonia yield and ambiguous reaction mechanism. Herein, phosphorus-doped carbon nanotube (P-CNTs) is developed as an efficient metal-free electrocatalyst for NRR with a remarkable NH3 yield of 24.4 μg·h−1·mg−1cat. and partial current density of 0.61 mA·cm−2. Such superior activity is found to be from P doping and highly conjugated CNTs substrate. Experimental and theoretical investigations discover that the electron-deficient phosphorus sites with Lewis acidity should be genuine active sites and NRR on P-CNTs follows the distal pathway. These findings provide insightful understanding on NRR processes on P-CNTs, opening up opportunities for the rational design of highly-active cost-effective metal-free catalysts for electrochemical ammonia synthesis.

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  1. [1]

    Kitano, M.; Inoue, Y.; Yamazaki, Y.; Hayashi, F.; Kanbara, S.; Matsuishi, S.; Yokoyama, T.; Kim, S. W.; Hara, M.; Hosono, H. Ammonia synthesis using a stable electride as an electron donor and reversible hydrogen store. Nat. Chem. 2012, 4, 934–940.

  2. [2]

    Suryanto, B. H. R.; Du, H. L.; Wang, D. B.; Chen, J.; Simonov, A. N.; MacFarlane, D. R. Challenges and prospects in the catalysis of electroreduction of nitrogen to ammonia. Nat. Catal. 2019, 2, 290–296.

  3. [3]

    Guo, C. X.; Ran, J. R.; Vasileff, A.; Qiao, S. Z. Rational design of electrocatalysts and photo(electro)catalysts for nitrogen reduction to ammonia (NH3) under ambient conditions. Energy Environ. Sci. 2018, 11, 45–56.

  4. [4]

    He, C.; Wu, Z. Y.; Zhao, L.; Ming, M.; Zhang, Y.; Yi, Y. P.; Hu, J. S. Identification of FeN4 as an efficient active site for electrochemical N2 reduction. ACS Catal. 2019, 9, 7311–7317.

  5. [5]

    Hao, Y. C.; Guo, Y.; Chen, L. W.; Shu, M.; Wang, X. Y.; Bu, T. A.; Gao, W. Y.; Zhang, N.; Su, X.; Feng, X. et al. Promoting nitrogen electroreduction to ammonia with bismuth nanocrystals and potassium cations in water. Nat. Catal. 2019, 2, 448–456.

  6. [6]

    Tao, H. C.; Choi, C.; Ding, L. X.; Jiang, Z.; Han, Z. S.; Jia, M. W.; Fan, Q.; Gao, Y. N.; Wang, H. H.; Robertson, A. W. et al. Nitrogen fixation by Ru single-atom electrocatalytic reduction. Chem2019, 5, 204–214.

  7. [7]

    Zhao, W. H.; Zhang, L. F.; Luo, Q. Q.; Hu, Z. P.; Zhang, W. H.; Smith, S.; Yang, J. L. Single Mo1(Cr1) atom on nitrogen-doped graphene enables highly selective electroreduction of nitrogen into ammonia. ACS Catal. 2019, 9, 3419–3425.

  8. [8]

    Qiu, W. B.; Xie, X. Y.; Qiu, J. D.; Fang, W. H.; Liang, R. P.; Ren, X.; Ji, X. Q.; Cui, G. W.; Asiri, A. M.; Cui, G. W. et al. High-performance artificial nitrogen fixation at ambient conditions using a metal-free electrocatalyst. Nat. Commun. 2018, 9, 3485.

  9. [9]

    Andersen, S. Z.; Čolić, V.; Yang, S.; Schwalbe, J. A.; Nielander, A. C.; McEnaney, J. M.; Enemark-Rasmussen, K.; Baker, J. G.; Singh, A. R.; Rohr, B. A. et al. A rigorous electrochemical ammonia synthesis protocol with quantitative isotope measurements. Nature2019, 570, 504–508.

  10. [10]

    Gao, X.; An, L.; Qu, D.; Jiang, W. S.; Chai, Y. X.; Sun, S. R.; Liu, X. Y.; Sun, Z. C. Enhanced photocatalytic N2 fixation by promoting N2 adsorption with a co-catalyst. Sci. Bull. 2019, 64, 918–925.

  11. [11]

    Zhao, Y. X.; Shi, R.; Bian, X. A.; Zhou, C.; Zhao, Y. F.; Zhang, S.; Wu, F.; Waterhouse, G. I. N.; Wu, L. Z.; Tung, C. H. et al. Ammonia detection methods in photocatalytic and electrocatalytic experiments: How to improve the reliability of NH3 production rates? Adv. Sci. 2019, 6, 1802109.

  12. [12]

    Yang, L. J.; Shui, J. L.; Du, L.; Shao, Y. Y.; Liu, J.; Dai, L. M.; Hu, Z. Carbon-based metal-free ORR electrocatalysts for fuel cells: Past, present, and future. Adv. Mater. 2019, 31, 1804799.

  13. [13]

    Zhao, S. L.; Wang, D. W.; Amal, R.; Dai, L. M. Carbon-based metalfree catalysts for key reactions involved in energy conversion and storage. Adv. Mater. 2019, 31, 1801526.

  14. [14]

    Duan, X. C.; Xu, J. T.; Wei, Z. X.; Ma, J. M.; Guo, S. J.; Wang, S. Y.; Liu, H. K.; Dou, S. X. Metal-free carbon materials for CO2 electrochemical reduction. Adv. Mater. 2017, 29, 1701784.

  15. [15]

    Zhang, J. T.; Xia, Z. H.; Dai, L. M. Carbon-based electrocatalysts for advanced energy conversion and storage. Sci. Adv. 2015, 1, e1500564.

  16. [16]

    Chen, C.; Yan, D. F.; Wang, Y.; Zhou, Y. Y.; Zou, Y. Q.; Li, Y. F.; Wang, S. Y. B–N pairs enriched defective carbon nanosheets for ammonia synthesis with high efficiency. Small2019, 15, 1805029.

  17. [17]

    Wang, W.; Shang, L.; Chang, G. J.; Yan, C. Y.; Shi, R.; Zhao, Y. X.; Waterhouse, G. I. N.; Yang, D. J.; Zhang, T. R. Intrinsic carbondefect- driven electrocatalytic reduction of carbon dioxide. Adv. Mater. 2019, 31, 1808276.

  18. [18]

    Gong, K. P.; Du, F.; Xia, Z. H.; Durstock, M.; Dai, L. M. Nitrogendoped carbon nanotube arrays with high electrocatalytic activity for oxygen reduction. Science2009, 323, 760–764.

  19. [19]

    Song, P. F.; Wang, H.; Kang, L.; Ran, B. C.; Song, H. H.; Wang, R. M. Electrochemical nitrogen reduction to ammonia at ambient conditions on nitrogen and phosphorus co-doped porous carbon. Chem. Commun. 2019, 55, 687–690.

  20. [20]

    Song, Y.; Johnson, D.; Peng, R.; Hensley, D. K.; Bonnesen, P. V.; Liang, L. B.; Huang, J. S.; Yang, F. C.; Zhang, F.; Qiao, R. et al. A physical catalyst for the electrolysis of nitrogen to ammonia. Sci. Adv. 2018, 4, e1700336.

  21. [21]

    Xia, L.; Wu, X. F.; Wang, Y.; Niu, Z. G.; Liu, Q.; Li, T. S.; Shi, X. F.; Asiri, A. M.; Sun, X. P. S-doped carbon nanospheres: An efficient electrocatalyst toward artificial N2 fixation to NH3. Small Methods2019, 3, 1800251.

  22. [22]

    Yu, X. M.; Han, P.; Wei, Z. X.; Huang, L. S.; Gu, Z. X.; Peng, S. J.; Ma, J. M.; Zheng, G. F. Boron-doped graphene for electrocatalytic N2 reduction. Joule2018, 2, 1610–1622.

  23. [23]

    Liu, Y. M.; Su, Y.; Quan, X.; Fan, X. F.; Chen, S.; Yu, H. T.; Zhao, H. M.; Zhang, Y. B..; Zhao, J. J. Facile ammonia synthesis from electrocatalytic N2 reduction under ambient conditions on N-doped porous carbon. ACS Catal. 2018, 8, 1186–1191.

  24. [24]

    Yuan, D.; Wei, Z. X.; Han, P.; Yang, C.; Huang, L. S.; Gu, Z. X.; Ding, Y.; Ma, J. M.; Zheng, G. F. Electron distribution tuning of fluorinedoped carbon for ammonia electrosynthesis. J. Mater. Chem. A2019, 7, 16979–16983.

  25. [25]

    Wang, Y. Q.; Zou, Y. Q.; Tao, L.; Wang, Y. Y.; Huang, G.; Du, S. Q.; Wang, S. Y. Rational design of three-phase interfaces for electrocatalysis. Nano Res. 2019, 12, 2055–2066.

  26. [26]

    Ji, S.; Wang, Z. X.; Zhao, J. X. A boron-interstitial doped C2N layer as a metal-free electrocatalyst for N2 fixation: A computational study. J. Mater. Chem. A2019, 7, 2392–2399.

  27. [27]

    Lv, C. D.; Qian, Y. M.; Yan, C. S.; Ding, Y.; Liu, Y. Y.; Chen, G.; Yu, G. H. Defect engineering metal-free polymeric carbon nitride electrocatalyst for effective nitrogen fixation under ambient conditions. Angew. Chem., Int. Ed. 2018, 57, 10246–10250.

  28. [28]

    Liu, H. M.; Wei, L.; Liu, F.; Pei, Z. X.; Shi, J.; Wang, Z. J.; He, D. H.; Chen, Y. Homogeneous, heterogeneous, and biological catalysts for electrochemical N2 reduction toward NH3 under ambient conditions. ACS Catal. 2019, 9, 5245–5267.

  29. [29]

    Lin, Y. M.; Wu, K. H.; Lu, Q.; Gu, Q. Q.; Zhang, L. Y.; Zhang, B. S.; Su, D. S.; Plodinec, M.; Schlögl, R.; Heumann, S. Electrocatalytic water oxidation at quinone-on-carbon: A model system study. J. Am. Chem. Soc. 2018, 140, 14717–14724.

  30. [30]

    Oh, S.; Gallagher, J. R.; Miller, J. T.; Surendranath, Y. Graphiteconjugated rhenium catalysts for carbon dioxide reduction. J. Am. Chem. Soc. 2016, 138, 1820–1823.

  31. [31]

    Luo, H.; Jiang, W. J.; Zhang, Y.; Niu, S.; Tang, T.; Huang, L. B.; Chen, Y. Y.; Wei, Z. D.; Hu, J. S. Self-terminated activation for high-yield production of N,P-codoped nanoporous carbon as an efficient metalfree electrocatalyst for Zn-air battery. Carbon2018, 128, 97–105.

  32. [32]

    Te Velde, G.; Bickelhaupt, F. M.; Baerends, E. J.; Fonseca Guerra, C.; Van Gisbergen, S. J. A.; Snijders, J. G.; Ziegler, T. Chemistry with ADF. J. Comput. Chem.2001, 22, 931–967.

  33. [33]

    Zhang, C. Z.; Mahmood, N.; Yin, H.; Liu, F.; Hou, Y. L. Synthesis of phosphorus-doped graphene and its multifunctional applications for oxygen reduction reaction and lithium ion batteries. Adv. Mater. 2013, 25, 4932–4937.

  34. [34]

    Yang, X. H.; Liu, P.; Zhou, D. L.; Gao, F.; Wang, X. H.; Lv, S. W.; Yuan, Z.; Jin, X.; Zhao, W.; Wei, H. M. et al. High temperature performance of coaxial h-BN/CNT wires above 1,000 °C: Thermionic electron emission and thermally activated conductivity. Nano Res. 2019, 12, 1855–1861.

  35. [35]

    Wang, R.; Dong, X. Y.; Du, J.; Zhao, J. Y.; Zang, S. Q. MOFderived bifunctional Cu3P nanoparticles coated by a N,P-codoped carbon shell for hydrogen evolution and oxygen reduction. Adv. Mater. 2018, 30, 1703711.

  36. [36]

    Chen, Y. Z.; Wang, C. M.; Wu, Z. Y.; Xiong, Y. J.; Xu, Q.; Yu, S. H.; Jiang, H. L. From bimetallic metal-organic framework to porous carbon: High surface area and multicomponent active dopants for excellent electrocatalysis. Adv. Mater. 2015, 27, 5010–5016.

  37. [37]

    Jiang, H. L.; Zhu, Y. H.; Feng, Q.; Su, Y. H.; Yang, X. L.; Li, C. Z. Nitrogen and phosphorus dual-doped hierarchical porous carbon foams as efficient metal-free electrocatalysts for oxygen reduction reactions. Chem.—Eur. J. 2014, 20, 3106–3112.

  38. [38]

    Yang, D. S.; Bhattacharjya, D.; Inamdar, S.; Park, J.; Yu, J. S. Phosphorus-doped ordered mesoporous carbons with different lengths as efficient metal-free electrocatalysts for oxygen reduction reaction in alkaline media. J. Am. Chem. Soc. 2012, 134, 16127–16130.

  39. [39]

    Geng, Z. G.; Liu, Y.; Kong, X. D.; Li, P.; Li, K.; Liu, Z. Y.; Du, J. J.; Shu, M.; Si, R.; Zeng, J. Achieving a record-high yield rate of 120.9 μgNH3•mg−1 cat.•h−1 for N2 electrochemical reduction over Ru single-atom catalysts. Adv. Mater. 2018, 30, 1803498.

  40. [40]

    Wang, Y.; Shi, M. M.; Bao, D.; Meng, F. L.; Zhang, Q.; Zhou, Y. T.; Liu, K. H.; Zhang, Y.; Wang, J. Z.; Chen, Z. W. et al. Generating defect-rich bismuth for enhancing the rate of nitrogen electroreduction to ammonia. Angew. Chem., Int. Ed. 2019, 58, 9464–9469.

  41. [41]

    Shi, M. M.; Bao, D.; Wulan, B. R.; Li, Y. H.; Zhang, Y. F.; Yan, J. M.; Jiang, Q. Au sub-nanoclusters on TiO2 toward highly efficient and selective electrocatalyst for N2 conversion to NH3 at ambient conditions. Adv. Mater. 2017, 29, 1606550.

  42. [42]

    Bao, D.; Zhang, Q.; Meng, F. L.; Zhong, H. X.; Shi, M. M.; Zhang, Y.; Yan, J. M.; Jiang, Q.; Zhang, X. B. Electrochemical reduction of N2 under ambient conditions for artificial N2 fixation and renewable energy storage using N2/NH3 cycle. Adv. Mater. 2017, 29, 1604799.

  43. [43]

    Nazemi, M.; Panikkanvalappil, S. R.; El-Sayed, M. A. Enhancing the rate of electrochemical nitrogen reduction reaction for ammonia synthesis under ambient conditions using hollow gold nanocages. Nano Energy2018, 49, 316–323.

  44. [44]

    Lv, C. D.; Yan, C. S.; Chen, G.; Ding, Y.; Sun, J. X.; Zhou, Y. S.; Yu, G. H. An amorphous noble-metal-free electrocatalyst that enables nitrogen fixation under ambient conditions. Angew. Chem., Int. Ed. 2018, 57, 6073–6076.

  45. [45]

    Wang, J.; Yu, L.; Hu, L.; Chen, G.; Xin, H. L.; Feng, X. F. Ambient ammonia synthesis via palladium-catalyzed electrohydrogenation of dinitrogen at low overpotential. Nat. Commun. 2018, 9, 1795.

  46. [46]

    Yao, Y.; Zhu, S. Q.; Wang, H. J.; Li, H.; Shao, M. H. A spectroscopic study on the nitrogen electrochemical reduction reaction on gold and platinum surfaces. J. Am. Chem. Soc. 2018, 140, 1496–1501.

  47. [47]

    Song, P. F.; Kang, L.; Wang, H.; Guo, R.; Wang, R. M. Nitrogen (N), phosphorus (P)-codoped porous carbon as a metal-free electrocatalyst for N2 reduction under ambient conditions. ACS Appl. Mater. Interfaces2019, 11, 12408–12414.

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We acknowledge the financial supports are from the National Key Research and Development Program of China (No. 2016YFB0101202), the National Natural Science Foundation of China (Nos. 91645123 and 21773263).

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Correspondence to Wen-Jie Jiang or Jin-Song Hu.

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This article is dedicated to Professor Charles M. Lieber in celebration of his 60th birthday. Worked with honor for 3 years under the supervision of Charlie in nanoplatform-enabled fundamental understanding of energy devices, J. S. H. gratefully acknowledges all the inspiration from Charlie that encourages to “think harder and work smarter” in persistently pursuing true science.

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Yuan, L., Wu, Z., Jiang, W. et al. Phosphorus-doping activates carbon nanotubes for efficient electroreduction of nitrogen to ammonia. Nano Res. (2020) doi:10.1007/s12274-020-2637-8

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  • P-doped carbon nanotubes
  • nitrogen reduction reaction
  • active sites
  • reaction pathway
  • electrocatalysis