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Hierarchically Assembled Cobalt Oxynitride Nanorods and N-Doped Carbon Nanofibers for Efficient Bifunctional Oxygen Electrocatalysis with Exceptional Regenerative Efficiency

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Abstract
Oxygen-based electrocatalysis is an integral aspect of a clean and sustainable energy conversion/storage system. The development of economic bifunctional electrocatalysts with high activity and durability during reversible reactions remains a great challenge. The tailored porous structure and separately presented active sites for oxygen reduction and oxygen evolution reactions (ORR and OER) without mutual interference are most crucial for achieving desired bifunctional catalysts. Here, we report a hybrid composed of sheath-core cobalt oxynitride (CoOx@CoNy) nanorods grown perpendicularly on N-doped carbon nanofiber (NCNF). The brushlike CoOx@CoNy nanorods, composed of metallic Co4N cores and oxidized surfaces, exhibit excellent OER activity (E = 1.69 V at 10 mA cm(-2)) in an alkaline medium. Although pristine NCNF or CoOx@CoNy alone had poor catalytic activity in the ORR, the hybrid showed dramatically enhanced ORR performance (E = 0.78 V at -3 mA cm(-2)). The experimental results coupled with a density functional theory (DFT) simulation confirmed that the broad surface area of the CoOx@CoNy nanorods with an oxidized skin layer boosts the catalytic OER, while the facile adsorption of ORR intermediates and a rapid interfacial charge transfer occur at the interface between the CoOx@CoNy nanorods and the electrically conductive NCNF. Furthermore, it was found that the independent catalytic active sites in the CoOx@CoNy/NCNF catalyst are continuously regenerated and sustained without mutual interference during the round-trip ORR/OER, affording stable operation of Zn-air batteries.
Author(s)
윤기로황창규김승훈정지원채지은김준이경아임아연조수호Jitendra Pal Singh김종민신기현문병무박현서김형준채근화함형철김일두김진영
Issued Date
2021
Type
Article
Keyword
cobalt oxynitridescarbon nanofibersbifunctional catalystsoxygen reduction reactionoxygen evolution reaction
DOI
10.1021/acsnano.0c09905
URI
https://oak.ulsan.ac.kr/handle/2021.oak/8820
https://ulsan-primo.hosted.exlibrisgroup.com/primo-explore/fulldisplay?docid=TN_cdi_proquest_miscellaneous_2543454327&context=PC&vid=ULSAN&lang=ko_KR&search_scope=default_scope&adaptor=primo_central_multiple_fe&tab=default_tab&query=any,contains,Hierarchically%20Assembled%20Cobalt%20Oxynitride%20Nanorods%20and%20N-Doped%20Carbon%20Nanofibers%20for%20Efficient%20Bifunctional%20Oxygen%20Electrocatalysis%20with%20Exceptional%20Regenerative%20Efficiency&offset=0&pcAvailability=true
Publisher
ACS NANO
Location
미국
Language
영어
ISSN
1936-0851
Citation Volume
15
Citation Number
7
Citation Start Page
11218
Citation End Page
11230
Appears in Collections:
Engineering > Aerospace Engineering
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