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Densely Populated Isolated Single CoN Site for Efficient Oxygen Electrocatalysis
Author(s) -
Wu Jiabin,
Zhou He,
Li Qun,
Chen Ming,
Wan Jun,
Zhang Nian,
Xiong Liukang,
Li Song,
Xia Bao Yu,
Feng Guang,
Liu Meilin,
Huang Liang
Publication year - 2019
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201900149
Subject(s) - bifunctional , electrocatalyst , catalysis , materials science , oxygen evolution , carbon fibers , graphene , reversible hydrogen electrode , oxygen , transition metal , cobalt , inorganic chemistry , chemical engineering , nanotechnology , electrode , electrochemistry , chemistry , working electrode , composite number , metallurgy , organic chemistry , composite material , engineering
Atomically dispersed transition metals confined with nitrogen on a carbon support has demonstrated great electrocatalytic performance, but an extremely low concentration of metal atoms (usually below 1.5%) is necessary to avoid aggregation through sintering which limits mass activity. Here, a salt‐template method to fabricate densely populated, monodispersed cobalt atoms on a nitrogen‐doped graphene‐like carbon support is reported, and achieving a dramatically higher site fraction of Co atoms (≈15.3%) in the catalyst and demonstrating excellent electrocatalytic activity for both the oxygen reduction reaction and oxygen evolution reaction. The atomic dispersion and high site fraction of Co provide a large electrochemically active surface area of ≈105.6 m 2 g −1 , leading to very high mass activity for ORR (≈12.164 A mg Co −1 at 0.8 V vs reversible hydrogen electrode), almost 10.5 times higher than that of the state‐of‐the‐art benchmark Pt/C catalyst (1.156 A mg Pt −1 under similar conditions). It also demonstrates an outstanding mass activity for OER (0.278 A mg Co −1 ). The Zn‐air battery based on this bifunctional catalyst exhibits high energy density of 945 Wh kg Zn −1 as well as remarkable stability. In addition, both density functional theory based simulations and experimental measurements suggest that the CoN 4 sites on the carbon matrix are the most active sites for the bifunctional oxygen electrocatalytic activity.