An efficient bifunctional electrocatalyst derived from layer-by-layer self-assembly of a three-dimensional porous Co-N-C@graphene

Shichang Cai; Rui Wang; William M Yourey; Junsheng Li; Haining Zhang; Haolin Tang

doi:10.1016/j.scib.2019.05.020

An efficient bifunctional electrocatalyst derived from layer-by-layer self-assembly of a three-dimensional porous Co-N-C@graphene

Sci Bull (Beijing). 2019 Jul 30;64(14):968-975. doi: 10.1016/j.scib.2019.05.020. Epub 2019 May 23.

Authors

Shichang Cai¹, Rui Wang¹, William M Yourey², Junsheng Li¹, Haining Zhang¹, Haolin Tang³

Affiliations

¹ State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China.
² College of Engineering, Penn State University, Hazleton, PA 18202, USA.
³ State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China. Electronic address: thln@whut.edu.cn.

PMID: 36659808
DOI: 10.1016/j.scib.2019.05.020

Abstract

Three-dimensional (3D) porous carbon-based materials with tunable composition and microstructure are of great interest for the development of oxygen involved electrocatalytic reactions. Here, we report the synthesis of 3D porous carbon-based electrocatalyst by self-assembling Co-metal organic frameworks (MOF) building blocks on graphene via a layer-by-layer technique. Precise control of the structure and morphology is achieved by varying the MOF layer to tune the electrocatalytic properties. The as-produced electrocatalyst exhibits an excellent catalytic activity for the oxygen reduction reaction in 0.1 mol L^-1 KOH, showing a high onset potential of 0.963 V vs. reversible hydrogen electrode (RHE) and a low tafel slope of 54 mV dec^-1, compared to Pt/C (0.934 V and 52 mV dec^-1, respectively). Additionally, it shows a slightly lower potential vs. RHE (1.72 V) than RuO₂ (1.75 V) at 10 mA cm^-2 in an alkaline electrolyte. A rechargeable Zn-air battery based on the as-produced 3D porous catalyst demonstrates a high peak power density of 119 mW cm^-2 at a cell voltage of 0.578 V while retaining an excellent stability over 250 charge-discharge cycles.

Keywords: Cobalt; Graphene; Oxygen evolution reaction; Oxygen reduction reaction; Three-dimensional.