title: Cobalt nanoparticles/nitrogen-doped graphene with high nitrogen doping efficiency as noble metal-free electrocatalysts for oxygen reduction reaction.
abstract: Nitrogen-doped graphene (N/GR) has been considered as active metal-free electrocatalysts for oxygen reduction reaction (ORR). However, the nitrogen (N) doping efficiency is very low and only few N atoms are doped into the framework of GR. To boost the N doping efficiency, in this work, a confined pyrolysis method with high N doping efficiency is used for the preparation of cobalt nanoparticles/nitrogen-doped GR (Co/N/GR). Under the protection of SiO2, the inorganic ligand NH3in cobalt amine complex ([Co(NH3)6]3+) is trapped in the confined space and then can be effectively doped into the framework of GR without the introduction of any carbon residues. Meanwhile, due to the redox reaction between the cobalt ions and carbon atoms of GR, Co nanoparticles are supported into the framework of N/GR. Due to prevention of GR layer aggregation with SiO2, the Co/N/GR with high dispersion provides sufficient surface area and maximum opportunity for the exposure of Co nanoparticles and active sites of N dopant. By combination of enhanced N doping efficiency, Co nanoparticles and high dispersion of GR sheets, the Co/N/GR is remarkably active, cheap and selective noble-metal free catalysts for ORR.
authors.affiliation: Department of Chemistry, Northeast Normal University, 5268 Renmin Street, Changchun, Jilin Province 130024, PR China.
authors.forename: Jingwen
authors.initials: J
authors.lastname: Liang
authors.affiliation: Department of Chemistry, Northeast Normal University, 5268 Renmin Street, Changchun, Jilin Province 130024, PR China.
authors.forename: Mehboob
authors.initials: M
authors.lastname: Hassan
authors.affiliation: Department of Chemistry, Northeast Normal University, 5268 Renmin Street, Changchun, Jilin Province 130024, PR China. Electronic address: zhuds206@nenu.edu.cn.
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Zhu
authors.affiliation: Department of Chemistry, Northeast Normal University, 5268 Renmin Street, Changchun, Jilin Province 130024, PR China.
authors.forename: Liping
authors.initials: L
authors.lastname: Guo
authors.affiliation: Department of Chemistry, Northeast Normal University, 5268 Renmin Street, Changchun, Jilin Province 130024, PR China. Electronic address: baoxj133@nenu.edu.cn.
authors.forename: Xiangjie
authors.initials: X
authors.lastname: Bo
keywords: Cobalt nanoparticles; High doping efficiency; Nitrogen-doped graphene; Noble metal-free electrocatalyst; Oxygen reduction reaction