N,O-codoped carbon spheres with uniform mesoporous entangled Co3O4 nanoparticles as a highly efficient electrocatalyst for oxygen reduction in a Zn-air battery

Yan Liu; Tao Zhang; Yu E Duan; Xin Dai; Qiang Tan; Yuanzhen Chen; Yongning Liu

doi:10.1016/j.jcis.2021.07.040

N,O-codoped carbon spheres with uniform mesoporous entangled Co₃O₄ nanoparticles as a highly efficient electrocatalyst for oxygen reduction in a Zn-air battery

J Colloid Interface Sci. 2021 Dec 15:604:746-756. doi: 10.1016/j.jcis.2021.07.040. Epub 2021 Jul 10.

Authors

Yan Liu¹, Tao Zhang², Yu E Duan³, Xin Dai¹, Qiang Tan¹, Yuanzhen Chen¹, Yongning Liu⁴

Affiliations

¹ State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, PR China.
² Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA.
³ School of Chemistry and Chemical Engineering, Xi'an University of Science and Technology, Xi'an 710054, PR China.
⁴ State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, PR China. Electronic address: ynliu@xjtu.edu.cn.

PMID: 34293532
DOI: 10.1016/j.jcis.2021.07.040

Abstract

Highly efficient electrochemical catalysts for oxygen reduction reactions (ORRs) are urgently needed for various energy conversion and storage devices to overcome sluggish ORR kinetics. Here, N,O-codoped carbon spheres with uniform mesopores and a high specific surface area were used as supports for decorating Co₃O₄ nanoparticles via a facile immersion route. In addition to the benefit of ions and gas mass transfer, the abundant mesopores present in the three-dimensional (3D) carbon spheres also confine and isolate the Co₃O₄ nanoparticles growing in it, which help to provide rich Co₃O₄ active sites. The resulting hybrid material exhibits superior ORR activity in terms of even-better half-wave potential and stability than that of commercial Pt/C (40 wt%) in 0.1 M KOH electrolyte. To verify its catalytic activity, the hybrid material was employed as the cathode catalyst in a flexible solid-state zinc-air battery, which achieves a high power density of 227 mW cm^-2; this power density is much higher than that of a Pt/C catalytic zinc-air battery (133 mW cm^-2) under identical conditions. The improvement in catalytic activity in both aqueous and nonaqueous electrolytes can be attributed to the abundant active sites of the entangled Co₃O₄ nanoparticles, as well as the novel N,O-codoped carbon structure.

Keywords: Entangled Co(3)O(4); N,O-codoped carbon spheres; Oxygen reduction reaction; Zn-air battery.