title: Order of Activity of Nitrogen, Iron Oxide, and FeNx Complexes towards Oxygen Reduction in Alkaline Medium.
abstract: In alkaline medium, it seems that both metal-free and iron-containing carbon-based catalysts, such as nitrogen-doped nanocarbon materials, FeOx -doped carbon, and Fe/N/C catalysts, are active for the oxygen reduction reaction (ORR). However, the order of activity of these different active compositions has not been clearly determined. Herein, we synthesized nitrogen-doped carbon black (NCB), Fe3 O4 /CB, Fe3 O4 /NCB, and FeN4 /CB. Through the systematic study of the ORR catalytic activity of these four catalysts in alkaline solution, we confirmed the difference in the catalytic activity and catalytic mechanism for nitrogen, iron oxides, and Fe-N complexes, respectively. In metal-free NCB, nitrogen can improve the ORR catalytic activity with a four-electron pathway. Fe3 O4 /CB catalyst did not exhibit improved activity over that of NCB owing to the poor conductivity and spinel structure of Fe3 O4 . However, FeN4 coordination compounds as the active sites showed excellent ORR catalytic activity.
authors.affiliation: School of Chemistry and Life Science, Anshan Normal University, Anshan, Liaoning, 114005, China.|Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, Liaoning, 110016, China.
authors.forename: Yansong
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, Liaoning, 110016, China.
authors.forename: Bingsen
authors.initials: B
authors.lastname: Zhang
authors.affiliation: School of Chemical Engineering, University of New South Wales, UNSW, Sydney, NSW, 2052, Australia.
authors.forename: Da-Wei
authors.initials: DW
authors.lastname: Wang
authors.affiliation: Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, Liaoning, 110016, China. dssu@imr.ac.cn.
authors.forename: Dang Sheng
authors.initials: DS
authors.lastname: Su
mesh_terms: D004563:Electrochemistry; D005290:Ferric Compounds / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*
chemical_list: D005290:Ferric Compounds; C000499:ferric oxide; D007501:Iron; D009584:Nitrogen; D010100:Oxygen
keywords: carbon; electrocatalyst; iron; nitrogen; oxygen reduction reaction