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High‐Performance Fe–N‐Doped Graphene Electrocatalysts with pH‐Dependent Active Sites for the Oxygen Reduction Reaction
Author(s) -
Pan Fuping,
Zhao Qiuping,
Wang Jia,
Zhang Junyan
Publication year - 2015
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.201500301
Subject(s) - graphene , catalysis , oxygen reduction , electrochemistry , oxygen reduction reaction , pyrolysis , urea , chemistry , doping , chemical engineering , nanoparticle , oxygen , annealing (glass) , materials science , inorganic chemistry , nanotechnology , electrode , metallurgy , organic chemistry , optoelectronics , engineering
Advanced Fe–N‐doped graphene (FeNG) electrocatalysts are developed for the oxygen reduction reaction (ORR) by annealing a mixture of sustainable and low‐cost corn starch, urea, and FeCl 3 . The Fe–N coordinations and Fe/Fe 3 C nanoparticles can be controllably achieved through space confinement and pyrolysis temperature‐induced effects, respectively. Electrochemical tests show that, compared to the commercial Pt/C catalyst, the ORR half‐wave potential of FeNG is 99 mV more positive in KOH and 34 mV more negative in H 2 SO 4 , with higher stabilities in both media. More importantly, the ORR mechanisms of FeNG are demonstrated to be diverse in both KOH and H 2 SO 4 , owing to the various catalytic centers. The obtained results indicate that the enhanced ORR activity in basic media can mainly be ascribed to quaternary N and Fe/Fe 3 C sites, whereas the ORR performance in acidic media originates primarily from Fe–N X complexes. The electrocatalytic origin of these species is governed, primarily, by their unique electronic structures and specific environments in different pH solutions.