Enhancing the crystallinity of covalent organic frameworks to achieve improved photocatalytic hydrogen peroxide production under ambient conditions

Photocatalytic production of hydrogen peroxide (H2 O2 ) presents a promising strategy for environmental remediation and energy production. However, achieving clean and efficient H2 O2 production under ambient conditions without organic sacrificial agents remains challenging. Enhancing the low crystallinity of covalent organic frameworks (COFs) can promote the separation and transmission of photo-generated carriers, thereby boosting their photocatalytic performance. Herein, we introduce a novel synthetic approach by substituting traditional acetic acid catalysts with organic base catalysts to enhance the crystallinity of beta-ketoenamine-linked COF, TpBD-COF. Compared to TpBD-COF-A synthesized using acetic acid catalysts, TpBD-COF-B, synthesized with organic base catalysts, exhibited advancements including increased absorption intensity in the visible spectrum, reduced photoluminescence intensity, enhanced photo-generated carrier separation performance, and a 2.1-fold increase in photocatalytic H2 O2 production. Under visible light irradiation, TpBDCOF-B achieved a photocatalytic H2 O2 production rate of 533 pmol/h/g using only air and water, without the need for organic sacrificial agents. Furthermore, TpBD-COF-B also exhibited good performance in long-term catalytic production experiments, tests with actual water bodies, and cyclic usage experiments. This study offers a strategy for enhancing the crystallinity of COFs to improve their photocatalytic activity, with promising applications in clean energy production and environmental remediation. (c) 2024 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.