Rational modification of hydroxy-functionalized covalent organic frameworks for enhanced photocatalytic hydrogen peroxide evolution

Hao Hu; Yinglong Tao; Di Wang; Changlai Li; Qichao Jiang; Yuexin Shi; Jian Wang; Jinping Qin; Shijian Zhou; Yan Kong

doi:10.1016/j.jcis.2022.09.111

Rational modification of hydroxy-functionalized covalent organic frameworks for enhanced photocatalytic hydrogen peroxide evolution

J Colloid Interface Sci. 2023 Jan;629(Pt B):750-762. doi: 10.1016/j.jcis.2022.09.111. Epub 2022 Sep 26.

Authors

Hao Hu¹, Yinglong Tao¹, Di Wang¹, Changlai Li¹, Qichao Jiang¹, Yuexin Shi¹, Jian Wang¹, Jinping Qin¹, Shijian Zhou², Yan Kong³

Affiliations

¹ State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical ·Engineering, Nanjing Tech University, Nanjing 210009, China.
² State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical ·Engineering, Nanjing Tech University, Nanjing 210009, China. Electronic address: zshijian@njtech.edu.cn.
³ State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical ·Engineering, Nanjing Tech University, Nanjing 210009, China. Electronic address: kongy36@njtech.edu.cn.

PMID: 36193619
DOI: 10.1016/j.jcis.2022.09.111

Abstract

Covalent organic frameworks (COFs), a class of flexibly tunable crystalline materials, have fascinating potential in photocatalytic hydrogen peroxide (H₂O₂) evolution under visible light irradiation. However, achieving efficient catalytic activity by tuning the composition of COFs and the linkages of building blocks is still a challenge. Herein, four imine-linked COFs with different numbers of hydroxy-functionalized are constructed to unveil the latent structure-activity relationship between the reversibility of bonding in supramolecular chemistry and the photocatalytic H₂O₂ performance. As the optimized material, TAPT-HTA-COF (1H-COF) containing single hydroxy group in aldehyde node exhibits a highest ordered structure and conjugation degree along and across the plane in the extended frameworks originating from the flexibly reversible iminol-to-ketoenamine tautomerism than others, which broadens the visible light absorption and accelerates the dissociation of photogenerated carriers in 1H-COF. These merits ensure that 1H-COF has the highest H₂O₂ yield (44.5 μmol L^-1) and O₂ two-electron reduction pathway among the four COFs under visible light irradiation (λ > 420 nm, 10 vol% isopropanol aqueous solution). At the same time, the long-range ordered framework of 1H-COF is well preserved during the photocatalytic H₂O₂ evolution process assisted by the proton-induced tautomerization. This work facilitates the design and development of COF-based photocatalysts in the evolution of H₂O₂.

Keywords: Covalent organic frameworks; H(2)O(2) evolution; Hydroxy functionalization; Keto-enol tautomerism; Photocatalysis.