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

作     者：Shichang Cai Rui Wang William M. Yourey Junsheng Li Haining Zhang Haolin Tang 

作者机构：State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China College of Engineering Penn State University Hazleton PA 18202 USA 

出 版 物：《Science Bulletin》 (科学通报（英文版）)

年 卷 期：2019年第64卷第14期

页      面：968-975页

核心收录：

学科分类：07[理学] 08[工学] 

基　　金：supported by the National Natural Science Foundation of China (51472187) 

主　　题：Oxygen reduction reaction Cobalt Three-dimensional Oxygen evolution reaction Graphene 

摘      要：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 0.1molL^-1 KOH, showing a high onset potential of 0.963V vs. reversible hydrogen electrode (RHE) and a low tafel slope of 54mVdec^-1, compared to Pt/C (0.934V and 52mVdec^-1, respectively). Additionally, it shows a slightly lower potential vs. RHE (1.72V) than RuO2 (1.75V) at 10mAcm^-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 119mWcm^-2 at a cell voltage of 0.578V while retaining an excellent stability over 250 charge-discharge cycles.