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Highly Active Carbon/α‐MnO 2 Hybrid Oxygen Reduction Reaction Electrocatalysts
Author(s) -
Chen Gao,
Sunarso Jaka,
Zhu Yanping,
Yu Jie,
Zhong Yijun,
Zhou Wei,
Shao Zongping
Publication year - 2016
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.201600433
Subject(s) - catalysis , oxide , graphene , mesoporous material , materials science , metal , chemical engineering , carbon nanotube , oxygen reduction reaction , hydrothermal circulation , carbon fibers , manganese oxide , manganese , nanotechnology , inorganic chemistry , chemistry , composite number , electrode , electrochemistry , composite material , organic chemistry , metallurgy , engineering
Manganese oxides are attractive catalyst candidates for the oxygen reduction reaction (ORR) given their natural abundance and low toxicity. α‐MnO 2 , in particular, exhibits high ORR activity in an alkaline medium. The hybrid concept provides a way to obtain enhanced ORR performance and long‐term durability through an optimized metal oxide–support interaction. Herein, we synthesized a carbon nanotube (CNT)–graphene–α‐MnO 2 hybrid in a hydrothermal reaction in which the MnO 2 nanosheets were deposited on the interior and exterior surfaces of the CNT channels. The resultant hybrid displayed very high ORR activity that is only marginally less than the performance of a commercial 20 wt % Pt/C catalyst and showed even better stability. The excellent ORR activity was attributed to two main factors, that is, the mesoporous architecture of the catalyst and the strong electron coupling between the encapsulated metal oxide and the support. We also showed that the preferential deposition of MnO 2 nanosheets within the CNT channels provides enhanced ORR performance relative to deposition on the exterior surfaces of the channels only. This in turn demonstrates unequivocally the confinement effect that the CNT exerts on the encapsulated metal oxide component, which can be exploited as a route to enhanced ORR activity.