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Thermally Driven Structure and Performance Evolution of Atomically Dispersed FeN 4 Sites for Oxygen Reduction
Author(s) -
Li Jiazhan,
Zhang Hanguang,
Samarakoon Widitha,
Shan Weitao,
Cullen David A.,
Karakalos Stavros,
Chen Mengjie,
Gu Daming,
More Karren L.,
Wang Guofeng,
Feng Zhenxing,
Wang Zhenbo,
Wu Gang
Publication year - 2019
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201909312
Subject(s) - carbonization , nitrogen , carbon fibers , chemistry , thermal stability , oxygen , inorganic chemistry , materials science , organic chemistry , adsorption , composite number , composite material
FeN 4 moieties embedded in partially graphitized carbon are the most efficient platinum group metal free active sites for the oxygen reduction reaction in acidic proton‐exchange membrane fuel cells. However, their formation mechanisms have remained elusive for decades because the Fe−N bond formation process always convolutes with uncontrolled carbonization and nitrogen doping during high‐temperature treatment. Here, we elucidate the FeN 4 site formation mechanisms through hosting Fe ions into a nitrogen‐doped carbon followed by a controlled thermal activation. Among the studied hosts, the ZIF‐8‐derived nitrogen‐doped carbon is an ideal model with well‐defined nitrogen doping and porosity. This approach is able to deconvolute Fe−N bond formation from complex carbonization and nitrogen doping, which correlates Fe−N bond properties with the activity and stability of FeN 4 sites as a function of the thermal activation temperature.