Modulating Core Polarity in Metal-free Covalent Organic Frameworks for Selective Electrocatalytic Hydrogen Peroxide Production

Shivangi Mehta; Nada Elmerhi; Sukhjot Kaur; Abdul Khayum Mohammed; Tharamani C Nagaiah; Dinesh Shetty

doi:10.1002/anie.202417403

Modulating Core Polarity in Metal-free Covalent Organic Frameworks for Selective Electrocatalytic Hydrogen Peroxide Production

Angew Chem Int Ed Engl. 2024 Oct 29:e202417403. doi: 10.1002/anie.202417403. Online ahead of print.

Authors

Shivangi Mehta¹, Nada Elmerhi^{2

3}, Sukhjot Kaur¹, Abdul Khayum Mohammed², Tharamani C Nagaiah¹, Dinesh Shetty^{2

3}

Affiliations

¹ Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar, Punjab, 140001, India.
² Department of Chemistry, Khalifa University of Science & Technology, Abu Dhabi, P.O. Box 127788, UAE.
³ Center for Catalysis & Separations (CeCaS), Khalifa University of Science & Technology, Abu Dhabi, P.O. Box 127788, UAE.

PMID: 39472302
DOI: 10.1002/anie.202417403

Abstract

Tuning the charge density at the active site to balance the adsorption ability and reactivity of oxygen is extremely significant for driving a two-electron oxygen reduction reaction (ORR) to produce hydrogen peroxide (H₂O₂). Herein, we have highlighted the influence of intermolecular polarity in covalent organic frameworks (COFs) on the efficiency and selectivity of electrochemical H₂O₂ production. Different C3 symmetric building blocks have been utilized to regulate the charge density at the active sites. The benzene-cored COF, which exhibits reduced polarity than the triazine-cored COF, displayed enhanced performance in H₂O₂ production, achieving 93.1 % selectivity for H₂O₂ at 0.4 V with almost two-electron transfer and a faradaic efficiency of 90.5 %. In-situ electrochemical Raman spectroscopy and scanning electrochemical microscopy (SECM) were employed to confirm H₂O₂ generation and analyze spatial reactivity patterns. These techniques provided detailed insights into localized catalytic behavior, emphasizing the influence of core polarity.

Keywords: H2O2 production; covalent organic frameworks; electrocatalysis; green production; metal-free catalyst.

Abstract

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