Premium
FeNC Electrocatalysts with Densely Accessible FeN 4 Sites for Efficient Oxygen Reduction Reaction
Author(s) -
Zhou Yazhou,
Chen Guangbo,
Wang Qing,
Wang Ding,
Tao Xiafang,
Zhang Tierui,
Feng Xinliang,
Müllen Klaus
Publication year - 2021
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202102420
Subject(s) - zeolitic imidazolate framework , reversible hydrogen electrode , materials science , melamine , proton exchange membrane fuel cell , electrolyte , carbon fibers , molecule , nitrogen , oxygen , inorganic chemistry , catalysis , electrode , metal organic framework , chemistry , organic chemistry , adsorption , reference electrode , composite number , composite material
The development of iron and nitrogen co‐doped carbon (FeNC) electrocatalysts for the oxygen reduction reaction (ORR) in proton‐exchange membrane fuel cells (PEMFCs) is a grand challenge due to the low density of accessible FeN 4 sites. Here, an in situ trapping strategy using nitrogen‐rich molecules (e.g., melamine, MA) is demonstrated to enhance the amount of accessible FeN 4 sites in FeNC electrocatalysts. The melamine molecules can participate in the coordination of Fe ions in zeolitic imidazolate frameworks to form FeN 6 sites within precursors. These FeN 6 sites are then converted into atomically dispersed FeN 4 sites during a pyrolytic process. Remarkably, the FeNC/MA exhibits a high single‐atom Fe content (3.5 wt.%), a large surface area (1160 m 2 g −1 ), and a high density of accessible FeN 4 sites (45.7 × 10 19 sites g −1 ). As a result, FeNC/MA shows a much enhanced ORR activity with a half‐wave potential of 0.83 V (vs the reversible hydrogen electrode) in a 0.5 m H 2 SO 4 electrolyte solution and a good performance in a PEMFC system with an activity of 80 mA cm −2 at 0.8 V under 1.0 bar H 2 /air. This work offers a promising approach toward high‐performance carbon‐based ORR electrocatalysts.