Developing nobel-metal-free catalysts, especially for iron-nitrogen on carbon (FeNC) materials, has been an urgent demand for wide applications of proton exchange membrane fuel cells (PEMFCs). However, the inferior oxygen reduction reaction (ORR) activity of traditional iron-nitrogen sites in acidic conditions seriously impedes the further improvement of their performance. Herein, we synthesized FeN4 with NO (nitric oxide) group axial modification (denoted as NO-FeN4) on a large scale through a confined small molecule synthesis strategy. Benefitting from the strong electron-withdrawing effect of the NO group, the central electron-rich FeN4 site exhibits ultrahigh ORR activity with a three times higher mass activity (1.1 A·g−1 at 0.85 V) compared to the traditional FeN4 sample, as well as full four-electron reaction selectivity. Moreover, the PEMFC assembled with the as-prepared electrocatalyst also exhibits a greatly enhanced peak power density (>725 mW·cm−2). This work provides a new approach to rationally design advanced M-Nx nonnoble electrocatalysts for the ORR.
Developing nobel-metal-free catalysts, especially for iron-nitrogen on carbon (FeNC) materials, has been an urgent demand for wide applications of proton exchange membrane fuel cells (PEMFCs). However, the inferior oxygen reduction reaction (ORR) activity of traditional iron-nitrogen sites in acidic conditions seriously impedes the further improvement of their performance. Herein, we synthesized FeN4 with NO (nitric oxide) group axial modification (denoted as NO-FeN4) on a large scale through a confined small molecule synthesis strategy. Benefitting from the strong electron-withdrawing effect of the NO group, the central electron-rich FeN4 site exhibits ultrahigh ORR activity with a three times higher mass activity (1.1 A·g−1 at 0.85 V) compared to the traditional FeN4 sample, as well as full four-electron reaction selectivity. Moreover, the PEMFC assembled with the as-prepared electrocatalyst also exhibits a greatly enhanced peak power density (>725 mW·cm−2). This work provides a new approach to rationally design advanced M-Nx nonnoble electrocatalysts for the ORR.
[1] |
Xiao F, Wang Y C, Wu Z P, et al. Recent advances in electrocatalysts for proton exchange membrane fuel cells and alkaline membrane fuel cells. Adv. Mater., 2021, 33: 2006292. doi: 10.1002/adma.202006292
|
[2] |
Jiao K, Xuan J, Du Q, et al. Designing the next generation of proton-exchange membrane fuel cells. Nature, 2021, 595: 361–369. doi: 10.1038/s41586-021-03482-7
|
[3] |
Debe M K. Electrocatalyst approaches and challenges for automotive fuel cells. Nature, 2012, 486: 43–51. doi: 10.1038/nature11115
|
[4] |
Martinez U, Komini Babu S, Holby E F, et al. Progress in the development of Fe-based PGM-free electrocatalysts for the oxygen reduction reaction. Adv. Mater., 2019, 31: 1806545. doi: 10.1002/adma.201806545
|
[5] |
Shao M, Chang Q, Dodelet J P, et al. Recent advances in electrocatalysts for oxygen reduction reaction. Chem. Rev., 2016, 116: 3594–3657. doi: 10.1021/acs.chemrev.5b00462
|
[6] |
Lefèvre M, Proietti E, Jaouen F, et al. Iron-based catalysts with improved oxygen reduction activity in polymer electrolyte fuel cells. Science, 2009, 324: 71–74. doi: 10.1126/science.1170051
|
[7] |
Jiang W J, Gu L, Li L, et al. Understanding the high activity of Fe-N-C electrocatalysts in oxygen reduction: Fe/Fe3C nanoparticles boost the activity of Fe-N x. J. Am. Chem. Soc., 2016, 138: 3570–3578. doi: 10.1021/jacs.6b00757
|
[8] |
Sa Y J, Seo D J, Woo J, et al. General approach to preferential formation of active Fe-N x Sites in Fe-N/C electrocatalysts for efficient oxygen reduction reaction. J. Am. Chem. Soc., 2016, 138: 15046–15056. doi: 10.1021/jacs.6b09470
|
[9] |
Chung H T, Cullen D A, Higgins D, et al. Direct atomic-level insight into the active sites of a high-performance PGM-free ORR catalyst. Science, 2017, 357: 479–484. doi: 10.1126/science.aan2255
|
[10] |
Lefèvre M, Dodelet J P. Fe-based catalysts for the reduction of oxygen in polymer electrolyte membrane fuel cell conditions: Determination of the amount of peroxide released during electroreduction and its influence on the stability of the catalysts. Electrochim. Acta, 2003, 48: 2749–2760. doi: 10.1016/S0013-4686(03)00393-1
|
[11] |
Kramm U I, Herrmann-Geppert I, Behrends J, et al. On an easy way to prepare metal nitrogen doped carbon with exclusive presence of MeN4-type sites active for the ORR. J. Am. Chem. Soc., 2016, 138: 635–640. doi: 10.1021/jacs.5b11015
|
[12] |
Jia Q Y, Ramaswamy N, Tylus U, et al. Spectroscopic insights into the nature of active sites in iron-nitrogen-carbon electrocatalysts for oxygen reduction in acid. Nano Energy, 2016, 29: 65–82. doi: 10.1016/j.nanoen.2016.03.025
|
[13] |
Bae G, Chung M W, Ji S G, et al. PH effect on the H2O2-induced deactivation of Fe-N-C catalysts. ACS Catal., 2020, 10: 8485–8495. doi: 10.1021/acscatal.0c00948
|
[14] |
Gupta S, Zhao S, Ogoke O, et al. Engineering favorable morphology and structure of Fe-N-C oxygen-reduction catalysts through tuning of nitrogen/carbon precursors. ChemSusChem, 2017, 10: 774–785. doi: 10.1002/cssc.201601397
|
[15] |
Wang Y C, Lai Y J, Song L, et al. S-doping of an Fe/N/C ORR catalyst for polymer electrolyte membrane fuel cells with high power density. Angew. Chem. Int. Ed., 2015, 54: 9907–9910. doi: 10.1002/anie.201503159
|
[16] |
Ni B X, Chen R, Wu L M, et al. Optimized enhancement effect of sulfur in Fe-N-S codoped carbon nanosheets for efficient oxygen reduction reaction. ACS Appl. Mater. Inter., 2020, 12: 23995–24006. doi: 10.1021/acsami.0c05095
|
[17] |
Dipojono H K, Saputro A G, Fajrial A K, et al. Oxygen reduction reaction mechanism on a phosporus-doped pyrolyzed graphitic Fe/N/C catalyst. New J. Chem., 2019, 43: 11408–11418. doi: 10.1039/C9NJ02118C
|
[18] |
Lefèvre M, Dodelet J P, Bertrand P. Molecular oxygen reduction in PEM fuel cells: Evidence for the simultaneous presence of two active sites in Fe-based catalysts. J. Phys. Chem. B, 2002, 106: 8705–8713. doi: 10.1021/jp020267f
|
[19] |
Zhang N, Zhou T P, Chen M L, et al. High-purity pyrrole-type FeN4 sites as a superior oxygen reduction electrocatalyst. Energ. Environ. Sci., 2020, 13: 111–118. doi: 10.1039/C9EE03027A
|
[20] |
Santoro C, Serov A, Gokhale R, et al. A family of Fe-N-C oxygen reduction electrocatalysts for microbial fuel cell (MFC) application: Relationships between surface chemistry and performances. Appl. Catal. B-Environ, 2017, 205: 24–33. doi: 10.1016/j.apcatb.2016.12.013
|
[21] |
Zitolo A, Goellner V, Armel V, et al. Identification of catalytic sites for oxygen reduction in iron- and nitrogen-doped graphene materials. Nat. Mater., 2015, 14: 937–942. doi: 10.1038/nmat4367
|
[22] |
Kurihara H, Ohta A, Fujisawa K. Structures and properties of dinitrosyl iron and cobalt complexes ligated by bis(3, 5-diisopropyl-1-pyrazolyl)methane. Inorganics, 2019, 7 (10): 116. doi: 10.3390/inorganics7100116
|
[23] |
Panomsuwan G, Saito N, Ishizaki T. Nitrogen-doped carbon nanoparticle-carbon nanofiber composite as an efficient metal-free cathode catalyst for oxygen reduction reaction. ACS Appl. Mater. Inter., 2016, 8: 6962–6971. doi: 10.1021/acsami.5b10493
|
[24] |
Yu H J, Shang L, Bian T, et al. Nitrogen-doped porous carbon nanosheets templated from g-C3N4 as metal-free electrocatalysts for efficient oxygen reduction reaction. Adv. Mater., 2016, 28: 5080–5086. doi: 10.1002/adma.201600398
|
[25] |
Buttersack C. Modeling of type IV and V sigmoidal adsorption isotherms. Phys. Chem. Chem. Phys., 2019, 21: 5614–5626. doi: 10.1039/C8CP07751G
|
[26] |
Xiao M L, Xing Z H, Jin Z, et al. Preferentially engineering FeN4 edge sites onto graphitic nanosheets for highly active and durable oxygen electrocatalysis in rechargeable Zn-Air batteries. Adv. Mater., 2020, 32: 2004900. doi: 10.1002/adma.202004900
|
[27] |
Fu X, Li N, Ren B, 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. doi: 10.1002/aenm.201803737
|
[28] |
Li J K, Ghoshal S, Liang W T, et al. Structural and mechanistic basis for the high activity of Fe-N-C catalysts toward oxygen reduction. Enegy. Environ. Sci., 2016, 9: 2418–2432. doi: 10.1039/C6EE01160H
|
[29] |
Novozhilova I V, Coppens P, Lee J, et al. Experimental and density functional theoretical investigations of linkage isomerism in six-coordinate {FeNO}6 iron porphyrins with axial nitrosyl and nitro ligands. J. Am. Chem. Soc., 2006, 128: 2093–2104. doi: 10.1021/ja0567891
|
[30] |
Tylus U, Jia Q Y, Strickland K, et al. Elucidating oxygen reduction active sites in pyrolyzed metal-nitrogen coordinated non-precious-metal electrocatalyst systems. J. Phys. Chem. C, 2014, 118: 8999–9008. doi: 10.1021/jp500781v
|
[31] |
Nie Y, Ding W, Wei Z D. Recent advancements of Pt-free catalysts for polymer electrolyte membrane fuel cells. CIESC Journal, 2015, 66: 3305–3318. doi: 10.11949/j.issn.0438-1157.20150785
|
[32] |
Gu J, Hsu C S, Bai L C, et al. Atomically dispersed Fe3+ sites catalyze efficient CO2 electroreduction to CO. Science, 2019, 364: 1091–1094. doi: 10.1126/science.aaw7515
|
[33] |
Zhang N, Zhou T P, Ge J K, et al. High-density planar-like Fe2N6 structure catalyzes efficient oxygen reduction. Matter, 2020, 3: 509–521. doi: 10.1016/j.matt.2020.06.026
|
Supporting_information.docx |
Figure 1. (a) Schematic representation of the synthesis for NO-FeN4. (b) HRTEM images of NO-FeN4 material. (c) HAADF-STEM images of NO-FeN4. (d) Elemental mapping images for the NO-FeN4. (e) N2 adsorption/desorption isotherms and corresponding pore size distribution curves (inset) of as-prepared NO-FeN4 product.
Figure 4. Electrocatalytic performance. (a) ORR polarization curves and (b) corresponding Tafel plots of NO-FeN4 and FeN4 in O2-saturated 0.5 mol·L−1 H2SO4 and 20% Pt/C in 0.1 mol·L−1 HClO4 under a rotating rate of 1600 r·min−1. (c) Comparison of mass activity at 0.85 V and half-wave potential of NO-FeN4 and FeN4 catalysts. (d) Peroxide yield and electron transfer number of NO-FeN4 and FeN4 sample during ORR process. (e) LSV curves of NO-FeN4 catalysts before and after 7000 CV cycles. (f) Polarization and power density curves of NO-FeN4 and FeN4 based membrane electrode assemblies in PEMFCs. Cell temperature: 80 ℃; RH: 100%, H2/O2: 1.5 bar.
Figure 5. (a) Schematic of operando XAS measurement device and three-electrode half-cell. (b) First derivative of XANES spectra of NO-FeN4 for dry powder and operando sample. (c) Operando XANES spectra of Fe K-edge for NO-FeN4. (d) Normalized difference spectra for Fe K-edge of NO-FeN4 at different potentials at operando condition.
[1] |
Xiao F, Wang Y C, Wu Z P, et al. Recent advances in electrocatalysts for proton exchange membrane fuel cells and alkaline membrane fuel cells. Adv. Mater., 2021, 33: 2006292. doi: 10.1002/adma.202006292
|
[2] |
Jiao K, Xuan J, Du Q, et al. Designing the next generation of proton-exchange membrane fuel cells. Nature, 2021, 595: 361–369. doi: 10.1038/s41586-021-03482-7
|
[3] |
Debe M K. Electrocatalyst approaches and challenges for automotive fuel cells. Nature, 2012, 486: 43–51. doi: 10.1038/nature11115
|
[4] |
Martinez U, Komini Babu S, Holby E F, et al. Progress in the development of Fe-based PGM-free electrocatalysts for the oxygen reduction reaction. Adv. Mater., 2019, 31: 1806545. doi: 10.1002/adma.201806545
|
[5] |
Shao M, Chang Q, Dodelet J P, et al. Recent advances in electrocatalysts for oxygen reduction reaction. Chem. Rev., 2016, 116: 3594–3657. doi: 10.1021/acs.chemrev.5b00462
|
[6] |
Lefèvre M, Proietti E, Jaouen F, et al. Iron-based catalysts with improved oxygen reduction activity in polymer electrolyte fuel cells. Science, 2009, 324: 71–74. doi: 10.1126/science.1170051
|
[7] |
Jiang W J, Gu L, Li L, et al. Understanding the high activity of Fe-N-C electrocatalysts in oxygen reduction: Fe/Fe3C nanoparticles boost the activity of Fe-N x. J. Am. Chem. Soc., 2016, 138: 3570–3578. doi: 10.1021/jacs.6b00757
|
[8] |
Sa Y J, Seo D J, Woo J, et al. General approach to preferential formation of active Fe-N x Sites in Fe-N/C electrocatalysts for efficient oxygen reduction reaction. J. Am. Chem. Soc., 2016, 138: 15046–15056. doi: 10.1021/jacs.6b09470
|
[9] |
Chung H T, Cullen D A, Higgins D, et al. Direct atomic-level insight into the active sites of a high-performance PGM-free ORR catalyst. Science, 2017, 357: 479–484. doi: 10.1126/science.aan2255
|
[10] |
Lefèvre M, Dodelet J P. Fe-based catalysts for the reduction of oxygen in polymer electrolyte membrane fuel cell conditions: Determination of the amount of peroxide released during electroreduction and its influence on the stability of the catalysts. Electrochim. Acta, 2003, 48: 2749–2760. doi: 10.1016/S0013-4686(03)00393-1
|
[11] |
Kramm U I, Herrmann-Geppert I, Behrends J, et al. On an easy way to prepare metal nitrogen doped carbon with exclusive presence of MeN4-type sites active for the ORR. J. Am. Chem. Soc., 2016, 138: 635–640. doi: 10.1021/jacs.5b11015
|
[12] |
Jia Q Y, Ramaswamy N, Tylus U, et al. Spectroscopic insights into the nature of active sites in iron-nitrogen-carbon electrocatalysts for oxygen reduction in acid. Nano Energy, 2016, 29: 65–82. doi: 10.1016/j.nanoen.2016.03.025
|
[13] |
Bae G, Chung M W, Ji S G, et al. PH effect on the H2O2-induced deactivation of Fe-N-C catalysts. ACS Catal., 2020, 10: 8485–8495. doi: 10.1021/acscatal.0c00948
|
[14] |
Gupta S, Zhao S, Ogoke O, et al. Engineering favorable morphology and structure of Fe-N-C oxygen-reduction catalysts through tuning of nitrogen/carbon precursors. ChemSusChem, 2017, 10: 774–785. doi: 10.1002/cssc.201601397
|
[15] |
Wang Y C, Lai Y J, Song L, et al. S-doping of an Fe/N/C ORR catalyst for polymer electrolyte membrane fuel cells with high power density. Angew. Chem. Int. Ed., 2015, 54: 9907–9910. doi: 10.1002/anie.201503159
|
[16] |
Ni B X, Chen R, Wu L M, et al. Optimized enhancement effect of sulfur in Fe-N-S codoped carbon nanosheets for efficient oxygen reduction reaction. ACS Appl. Mater. Inter., 2020, 12: 23995–24006. doi: 10.1021/acsami.0c05095
|
[17] |
Dipojono H K, Saputro A G, Fajrial A K, et al. Oxygen reduction reaction mechanism on a phosporus-doped pyrolyzed graphitic Fe/N/C catalyst. New J. Chem., 2019, 43: 11408–11418. doi: 10.1039/C9NJ02118C
|
[18] |
Lefèvre M, Dodelet J P, Bertrand P. Molecular oxygen reduction in PEM fuel cells: Evidence for the simultaneous presence of two active sites in Fe-based catalysts. J. Phys. Chem. B, 2002, 106: 8705–8713. doi: 10.1021/jp020267f
|
[19] |
Zhang N, Zhou T P, Chen M L, et al. High-purity pyrrole-type FeN4 sites as a superior oxygen reduction electrocatalyst. Energ. Environ. Sci., 2020, 13: 111–118. doi: 10.1039/C9EE03027A
|
[20] |
Santoro C, Serov A, Gokhale R, et al. A family of Fe-N-C oxygen reduction electrocatalysts for microbial fuel cell (MFC) application: Relationships between surface chemistry and performances. Appl. Catal. B-Environ, 2017, 205: 24–33. doi: 10.1016/j.apcatb.2016.12.013
|
[21] |
Zitolo A, Goellner V, Armel V, et al. Identification of catalytic sites for oxygen reduction in iron- and nitrogen-doped graphene materials. Nat. Mater., 2015, 14: 937–942. doi: 10.1038/nmat4367
|
[22] |
Kurihara H, Ohta A, Fujisawa K. Structures and properties of dinitrosyl iron and cobalt complexes ligated by bis(3, 5-diisopropyl-1-pyrazolyl)methane. Inorganics, 2019, 7 (10): 116. doi: 10.3390/inorganics7100116
|
[23] |
Panomsuwan G, Saito N, Ishizaki T. Nitrogen-doped carbon nanoparticle-carbon nanofiber composite as an efficient metal-free cathode catalyst for oxygen reduction reaction. ACS Appl. Mater. Inter., 2016, 8: 6962–6971. doi: 10.1021/acsami.5b10493
|
[24] |
Yu H J, Shang L, Bian T, et al. Nitrogen-doped porous carbon nanosheets templated from g-C3N4 as metal-free electrocatalysts for efficient oxygen reduction reaction. Adv. Mater., 2016, 28: 5080–5086. doi: 10.1002/adma.201600398
|
[25] |
Buttersack C. Modeling of type IV and V sigmoidal adsorption isotherms. Phys. Chem. Chem. Phys., 2019, 21: 5614–5626. doi: 10.1039/C8CP07751G
|
[26] |
Xiao M L, Xing Z H, Jin Z, et al. Preferentially engineering FeN4 edge sites onto graphitic nanosheets for highly active and durable oxygen electrocatalysis in rechargeable Zn-Air batteries. Adv. Mater., 2020, 32: 2004900. doi: 10.1002/adma.202004900
|
[27] |
Fu X, Li N, Ren B, 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. doi: 10.1002/aenm.201803737
|
[28] |
Li J K, Ghoshal S, Liang W T, et al. Structural and mechanistic basis for the high activity of Fe-N-C catalysts toward oxygen reduction. Enegy. Environ. Sci., 2016, 9: 2418–2432. doi: 10.1039/C6EE01160H
|
[29] |
Novozhilova I V, Coppens P, Lee J, et al. Experimental and density functional theoretical investigations of linkage isomerism in six-coordinate {FeNO}6 iron porphyrins with axial nitrosyl and nitro ligands. J. Am. Chem. Soc., 2006, 128: 2093–2104. doi: 10.1021/ja0567891
|
[30] |
Tylus U, Jia Q Y, Strickland K, et al. Elucidating oxygen reduction active sites in pyrolyzed metal-nitrogen coordinated non-precious-metal electrocatalyst systems. J. Phys. Chem. C, 2014, 118: 8999–9008. doi: 10.1021/jp500781v
|
[31] |
Nie Y, Ding W, Wei Z D. Recent advancements of Pt-free catalysts for polymer electrolyte membrane fuel cells. CIESC Journal, 2015, 66: 3305–3318. doi: 10.11949/j.issn.0438-1157.20150785
|
[32] |
Gu J, Hsu C S, Bai L C, et al. Atomically dispersed Fe3+ sites catalyze efficient CO2 electroreduction to CO. Science, 2019, 364: 1091–1094. doi: 10.1126/science.aaw7515
|
[33] |
Zhang N, Zhou T P, Ge J K, et al. High-density planar-like Fe2N6 structure catalyzes efficient oxygen reduction. Matter, 2020, 3: 509–521. doi: 10.1016/j.matt.2020.06.026
|