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Hierarchically Porous M–N–C (M = Co and Fe) Single‐Atom Electrocatalysts with Robust MN x Active Moieties Enable Enhanced ORR Performance
Author(s) -
Zhu Chengzhou,
Shi Qiurong,
Xu Bo Z.,
Fu Shaofang,
Wan Gang,
Yang Ce,
Yao Siyu,
Song Junhua,
Zhou Hua,
Du Dan,
Beckman Scott P.,
Su Dong,
Lin Yuehe
Publication year - 2018
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.201801956
Subject(s) - catalysis , materials science , active site , electrochemistry , density functional theory , reversible hydrogen electrode , nanotechnology , atom (system on chip) , chemical engineering , combinatorial chemistry , electrode , chemistry , computational chemistry , working electrode , computer science , organic chemistry , engineering , embedded system
The great interest in fuel cells inspires a substantial amount of research on nonprecious metal catalysts as alternatives to Pt‐based oxygen reduction reaction (ORR) electrocatalysts. In this work, bimodal template‐based synthesis strategies are proposed for the scalable preparation of hierarchically porous M–N–C (M = Fe or Co) single‐atom electrocatalysts featured with active and robust MN 2 active moieties. Multiscale tuning of M–N–C catalysts regarding increasing the number of active sites and boosting the intrinsic activity of each active site is realized simultaneously at a single‐atom scale. In addition to the antipoisoning power and high affinity for O 2 , the optimized Fe–N–C catalysts with FeN 2 active site presents a superior electrocatalytic activity for ORR with a half‐wave potential of 0.927 V (vs reversible hydrogen electrode (RHE)) in an alkaline medium, which is 49 and 55 mV higher than those of the Co–N–C counterpart and commercial Pt/C, respectively. Density functional theory calculations reveal that the FeN 2 site is more active than the CoN 2 site for ORR due to the lower energy barriers of the intermediates and products involved. The present work may help rational design of more robust ORR electrocatalysts at the atomic level, realizing the significant advances in electrochemical conversion and storage devices.