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One-Step Preparation of Fe/N/C Single-Atom Catalysts Containing Fe?N4 Sites from an Iron Complex Precursor with 5,6,7,8-Tetraphenyl-1,12-Diazatriphenylene Ligands |
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| Authors: | Koki Matsumoto Dr Masaru Kato Prof Ichizo Yagi Siqi Xie Prof Kiyotaka Asakura Prof Shin-ichiro Noro Prof Norimitsu Tohnai Dr Stéphane Campidelli Prof Takashi Hayashi Prof Akira Onoda |
| Institution: | 1. Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, 565-0871 Japan
Graduate School of Environmental Science, Hokkaido University, North 10 West 5, Kita-ku, Sapporo, 060-0810 Japan;2. Faculty of Environmental Earth Science, Hokkaido University, North 10 West 5, Kita-ku, Sapporo, 060-0810 Japan Graduate School of Environmental Science, Hokkaido University, North 10 West 5, Kita-ku, Sapporo, 060-0810 Japan;3. Graduate School of Environmental Science, Hokkaido University, North 10 West 5, Kita-ku, Sapporo, 060-0810 Japan;4. Institute for Catalysis, Hokkaido University, North 21 West 10, Kita-ku, Sapporo, 001-0021 Japan;5. Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, 565-0871 Japan;6. Université Paris-Saclay, CEA, CNRS, NIMBE, LICSEN, 91191 Gif-sur-Yvette, France;7. Faculty of Environmental Earth Science, Hokkaido University, North 10 West 5, Kita-ku, Sapporo, 060-0810 Japan |
| Abstract: | Fe/N/C single-atom catalysts containing Fe?Nx sites prepared by pyrolysis are promising cathode materials for fuel cells and metal-air batteries due to their high oxygen reduction reaction (ORR) activities. We have developed iron complexes containing N2- or N3-chelating coordination structures with preorganized aromatic rings in a 1,12-diazatriphenylene framework tethering bromo substituents as precursors to precisely construct Fe?N4 sites in an Fe/N/C catalyst. One-step pyrolysis of the iron complex with carbon black forms atomically dispersed Fe?N4 sites without iron aggregates. X-ray absorption spectroscopy (XAS) and electrochemical measurements revealed that the iron complex with N3-coordination is more effectively converted to Fe?N4 sites catalyzing ORR with a TOF value of 0.21 e site?1 s?1 at 0.8 V vs. RHE. This indicates that the formation of Fe?N4 sites is controlled by precise tuning of the chemical structure of the iron complex precursor. |
| Keywords: | Fe/N/C single-atom catalysts Fe?N4 sites iron-diazatriphenylene complexes one-step preparation oxygen reduction reaction (ORR) |