title: Nitrogen-Doped Graphene with Pyridinic Dominance as a Highly Active and Stable Electrocatalyst for Oxygen Reduction.
abstract: The nitrogen-doped graphene (NG) with dominance of the pyridinic-N configuration is synthesized via a straightforward process including chemical vapor deposition (CVD) growth of graphene and postdoping with a solid nitrogen precursor of graphitic C3N4 at elevated temperature. The NG fabricated from CVD-grown graphene contains a high N content up to 6.5 at. % when postdoped at 800 °C but maintains high crystalline quality of graphene. The obtained NG exhibits high activity, long-standing stability, and outstanding crossover resistance for electrocatalysis of oxygen reduction reaction (ORR) in alkaline medium. The NG treated at 800 °C shows the best ORR performance. Further study of the dependence of ORR activity on different N functional groups in these metal-free NG electrodes provides deeper insights into the origin of ORR activity. Our results reveal that the pyridinic-N tends to be the most active N functional group to facilitate ORR at low overpotential via a four-electron pathway.
authors.affiliation: Department of Material Science and NanoEngineering, Rice University, Houston, Texas 77005, United States.
authors.forename: Jingjie
authors.initials: J
authors.lastname: Wu
authors.affiliation: Department of Material Science and NanoEngineering, Rice University, Houston, Texas 77005, United States.
authors.forename: Lulu
authors.initials: L
authors.lastname: Ma
authors.affiliation: Department of Material Science and NanoEngineering, Rice University, Houston, Texas 77005, United States.
authors.forename: Ram Manohar
authors.initials: RM
authors.lastname: Yadav
authors.affiliation: Department of Material Science and NanoEngineering, Rice University, Houston, Texas 77005, United States.
authors.forename: Yingchao
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Department of Material Science and NanoEngineering, Rice University, Houston, Texas 77005, United States.
authors.forename: Xiang
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Material Science and NanoEngineering, Rice University, Houston, Texas 77005, United States.
authors.forename: Robert
authors.initials: R
authors.lastname: Vajtai
authors.affiliation: Department of Material Science and NanoEngineering, Rice University, Houston, Texas 77005, United States.
authors.forename: Jun
authors.initials: J
authors.lastname: Lou
authors.affiliation: Department of Material Science and NanoEngineering, Rice University, Houston, Texas 77005, United States.
authors.forename: Pulickel M
authors.initials: PM
authors.lastname: Ajayan
keywords: low defect; metal-free; nitrogen functionality; nitrogen-doped graphene; oxygen reduction reaction; pyridinic nitrogen