Structural and Electronic Modulations of Imidazolium Covalent Organic Framework-Derived Electrocatalysts for Oxygen Redox Reactions in Rechargeable Zn-Air Batteries

Jong Min Ju, Chi Ho Lee, Jung Hyun Park, Jun Hyeong Lee, Hajin Lee, Jae Hoon Shin, Seon Yeong Kwak, Sang Uck Lee, Jong Ho Kim

Research output: Contribution to journalArticlepeer-review

Abstract

Covalent organic frameworks (COFs) are promising candidates for the controllable design of electrocatalysts. However, bifunctional electrocatalytic activities for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) remain challenging in COFs. In this study, imidazolium-rich COFs (IMCOFs) with well-defined active sites and characteristic three-dimensional assembly structures were readily prepared, and their electronic structures were tuned by Co incorporation to elicit bifunctional electrocatalytic activities for the ORR and OER. The Co nanoparticle-incorporated spherical IMCOF-derived electrocatalyst (CoNP-s-IMCOF) exhibited lower overpotentials for the ORR and OER compared with the atomic Co-incorporated planar IMCOF-derived electrocatalyst (Co-p-IMCOF). Computational simulations revealed that the imidazole carbon sites of CoNP-s-IMCOF rather than the triazine carbons were the active sites for the ORR and OER, and its p-band center downshifted via charge transfer, facilitating the chemisorption of oxygen intermediates during the reactions. A Zn-air battery with CoNP-s-IMCOF exhibited a small voltage gap of 1.3 V with excellent durability for 935 cycles. This approach for control over the three-dimensional assembly and electronic structures of IMCOFs can be extended to the development of diverse catalytic nanomaterials for applications of interest.

Original languageEnglish (US)
Pages (from-to)24404-24414
Number of pages11
JournalACS Applied Materials and Interfaces
Volume14
Issue number21
DOIs
StatePublished - Jun 1 2022
Externally publishedYes

Keywords

  • bifunctional electrocatalyst
  • imidazolium-rich covalent organic framework
  • oxygen evolution reaction
  • oxygen reduction reaction
  • Zn-air battery

ASJC Scopus subject areas

  • General Materials Science

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