Oxygen Reduction Reaction in a Droplet on Graphite: Direct Evidence that the Edge Is More Active than the Basal Plane

Carbon‐based metal‐free electrocatalysts for the oxygen reduction reaction (ORR) in alkaline medium have been extensively investigated with the aim of replacing the commercially available, but precious platinum‐based catalysts. For the proper design of carbon‐based metal‐free electrocatalysts for th...

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Published in:Angewandte Chemie International Edition Vol. 53; no. 40; pp. 10804 - 10808
Main Authors: Shen, Anli, Zou, Yuqin, Wang, Qiang, Dryfe, Robert A. W., Huang, Xiaobing, Dou, Shuo, Dai, Liming, Wang, Shuangyin
Format: Journal Article
Language:English
Published: Weinheim WILEY-VCH Verlag 26-09-2014
WILEY‐VCH Verlag
Wiley Subscription Services, Inc
Edition:International ed. in English
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Summary:Carbon‐based metal‐free electrocatalysts for the oxygen reduction reaction (ORR) in alkaline medium have been extensively investigated with the aim of replacing the commercially available, but precious platinum‐based catalysts. For the proper design of carbon‐based metal‐free electrocatalysts for the ORR, it would be interesting to identify the active sites of the electrocatalyst. The ORR was now studied with an air‐saturated electrolyte solution droplet (diameter ca. 15 μm), which was deposited at a specified position either on the edge or on the basal plane of highly oriented pyrolytic graphite. Electrochemical measurements suggest that the edge carbon atoms are more active than the basal‐plane ones for the ORR. This provides a direct way to identify the active sites of carbon materials for the ORR. Ball‐milled graphite and carbon nanotubes with more exposed edges were also prepared and showed significantly enhanced ORR activity. DFT calculations elucidated the mechanism by which the charged edge carbon atoms result in the higher ORR activity. On the cutting edge: To study the oxygen reduction reaction (ORR), an air‐saturated electrolyte solution droplet with a diameter of approximately 15 μm was deposited at a specified position on the edge (see picture) or on the basal plane of highly oriented pyrolytic graphite. Electrochemical measurements suggest that the edge sites are catalytically more active than basal‐plane sites towards the ORR.
Bibliography:AFOSR MURI - No. FA9550-12-1-0037
National Science Foundation - No. IIP-1343270; No. CMMI-133123
Inter-discipline Research Program of Hunan University
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ark:/67375/WNG-HS3HQSH1-W
ArticleID:ANIE201406695
Youth 1000 Talent Program of China
We acknowledge support from AFOSR MURI (FA9550-12-1-0037), the National Science Foundation (IIP-1343270 and CMMI-133123), the Youth 1000 Talent Program of China, and the Inter-discipline Research Program of Hunan University.
We acknowledge support from AFOSR MURI (FA9550‐12‐1‐0037), the National Science Foundation (IIP‐1343270 and CMMI‐133123), the Youth 1000 Talent Program of China, and the Inter‐discipline Research Program of Hunan University.
These authors contributed equally to this work.
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ISSN:1433-7851
1521-3773
DOI:10.1002/anie.201406695