Cation-assisted water oxidation with crown ether-based covalent organic frameworks

Pal, H, Karmakar, A, Sadhukhan, A, Sharma, R, Paul, S, Addicoat, MA ORCID: https://orcid.org/0000-0002-5406-7927, Nishiyama, Y, Pathak, B, Kundu, S and Banerjee, R, 2025. Cation-assisted water oxidation with crown ether-based covalent organic frameworks. Journal of the American Chemical Society, 147 (24), 20406–20416. ISSN 0002-7863

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Abstract

Covalent Organic Framework-based electrocatalysts for water oxidation are usually designed by inducing polarization into an organic framework. The most common methodology, "heteroatom insertion" suffers from lower catalytic activity than metalated systems. Herein, we introduce a strategy of polarity induction into organic frameworks by complexing electrolyte's alkali metal using crown ether. We have synthesized a series of porous crystalline covalent organic frameworks (COFs) with different sizes of crown ether units, having different alkali metal binding abilities. COF-catalysts having crown ethers in their backbone show oxygen and hydrogen evolution (OER & HER) performance in alkaline electrolytes. Electrocatalytic performances of various COF-catalysts have also been studied while changing the alkali metal of the electrolyte solution. The most efficient catalyst B18C achieved a current density of 20 and 100 mA cm-2 at an overpotential (ɳ20 and ɳ100) 287 ± 1 and 362 ± 8 mV (for OER) in 1 M KOH (pH = 13.6), with a good electrocatalytic stability (16 h chronopotentiometry study showed 2 mV potential change at 25 mA cm-2 current density). Notably, B18C COF also exhibited good OER performance in a 1 M K2SO4 (pH = 6.3) with an overpotential (ɳ20) of 471 mV. Additionally, a promising alkaline HER activity of B18C (ɳ20 = 310 ± 5 mV) leads to an overall water-splitting performance in 1 M KOH (Ecell = 1.784 V @ 20 mA cm-2).

Item Type:	Journal article
Publication Title:	Journal of the American Chemical Society
Creators:	Pal, H., Karmakar, A., Sadhukhan, A., Sharma, R., Paul, S., Addicoat, M.A., Nishiyama, Y., Pathak, B., Kundu, S. and Banerjee, R.
Publisher:	American Chemical Society
Date:	6 June 2025
Volume:	147
Number:	24
ISSN:	0002-7863
Identifiers:	Number Type 10.1021/jacs.5c02083 DOI 2451038 Other
Rights:	This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of the American Chemical Society, copyright © 2024 American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/jacs.5c02083
Divisions:	Schools > School of Science and Technology
Record created by:	Jonathan Gallacher
Date Added:	24 Jun 2025 14:25
Last Modified:	24 Jun 2025 14:25
URI:	https://irep.ntu.ac.uk/id/eprint/53791

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