title: Cobalt nanoparticles embedded in N-doped carbon as an efficient bifunctional electrocatalyst for oxygen reduction and evolution reactions.
abstract: Cobalt based catalysts are promising bifunctional electrocatalysts for both oxygen reduction and oxygen evolution reactions (ORR and OER) in unitized regenerative fuel cells (URFCs) operating with alkaline electrolytes. Here we report a hybrid composite of cobalt nanoparticles embedded in nitrogen-doped carbon (Co/N-C) via a solvothermal carbonization strategy. With the synergistic effect arising from the N-doped carbon and cobalt nanoparticles in the composite, the Co/N-C hybrid catalyst exhibits highly efficient bifunctional catalytic activity and excellent stability toward both ORR and OER. The ΔE (oxygen electrode activity parameter for judging the overall electrocatalytic activity of a bifunctional electrocatalyst) value for Co/N-C is 0.859 V, which is smaller than those of Pt/C and most of the non-precious metal catalysts in previous studies. Furthermore, the Co/N-C composite also shows better bifunctional catalytic activity than its oxidative counterparts, which could be attributed to the high specific surface area and the efficient charge transfer ability of the composite, as well as the good synergistic effect between N-doped carbon and the Co nanoparticles in the Co/N-C composite.
authors.affiliation: Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China. yhzhu@ecust.edu.cn jiandingchen@ecust.edu.cn.
authors.forename: Yunhe
authors.initials: Y
authors.lastname: Su
authors.forename: Yihua
authors.initials: Y
authors.lastname: Zhu
authors.forename: Hongliang
authors.initials: H
authors.lastname: Jiang
authors.forename: Jianhua
authors.initials: J
authors.lastname: Shen
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Yang
authors.forename: Wenjian
authors.initials: W
authors.lastname: Zou
authors.forename: Jianding
authors.initials: J
authors.lastname: Chen
authors.forename: Chunzhong
authors.initials: C
authors.lastname: Li