Excavated Fe-N-C sites for enhanced electrocatalytic activity in the oxygen reduction reaction.
Platinum (Pt) is the best electrocatalyst for the oxygen reduction reaction (ORR) in hydrogen fuel cells, but it is an extremely expensive resource. The successful development of a cost-effective non-Pt ORR electrocatalyst will be a breakthrough for the commercialization of hydrogen-air fuel cells. Ball milling has been used to incorporate metal and nitrogen precursors into micropores of carbon more effectively and in the direct nitrogen-doping of carbon under highly pressurized nitrogen gas in the process of the preparation of non-noble ORR catalysts. In this study, we first utilize ball milling to excavate the ORR active sites embedded in Fe-modified N-doped carbon nanofibers (Fe-N-CNFs) by pulverization. The facile ball-milling process resulted in a significant enhancement in the ORR activity and the selectivity of the Fe-N-CNFs owing to the higher exposure of the metal-based catalytically active sites. The degree of excavation of the Fe-based active sites in the Fe-N-CNFs for the ORR was investigated with cyclic voltammetry, X-ray photoelectron spectroscopy, and pore-size distribution analysis. We believe that this simple approach is useful to improve alternative ORR electrocatalysts up to the level necessary for practical applications.
School of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712 (South Korea).
Beomgyun
B
Jeong
Dongyoon
D
Shin
Hongrae
H
Jeon
Joey D
JD
Ocon
Bongjin Simon
BS
Mun
Jaeyoon
J
Baik
Hyun-Joon
HJ
Shin
Jaeyoung
J
Lee
D002244:Carbon / Q000737:chemistry*; D002384:Catalysis; D055664:Electrochemical Techniques; D007501:Iron / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D057139:Nanofibers / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D016062:Porosity; D013499:Surface Properties
D002244:Carbon; D007501:Iron; D009584:Nitrogen; D010100:Oxygen
electrocatalysts; fuel cells; iron; nanostructures; reduction