Overcoming Photochemical Limitations in Covalent Organic Frameworks: Low‐Energy Light Driven Selective ¹ O ₂ Generation Achieved by Donor–Acceptor Strategy

Abstract

Abstract Singlet oxygen ( 1 O 2 ) plays a crucial role in various photocatalytic oxidation reactions; however, achieving high‐efficiency and selective 1 O 2 production under low‐energy light remains a challenge. Herein, we present a novel donor–acceptor (D–A) strategy in covalent organic frameworks (COFs) to regulate the localized electronic state structures for efficient and selective 1 O 2 generation under low‐energy light. Notably, the rationally incorporation of the negatively charged carbonyl groups into the basal plane of the COF strengthens the D–A interaction, improves light harvesting in the lower‐energy region, and facilitates highly selective 1 O 2 generation through a coupled charge‐transfer mechanism. As a result, the engineered COF demonstrates exceptional photocatalytic performance in 1 O 2 driven advanced oxidation, enabling gram‐scale production under red light, even when operating through translucent barriers. A mechanistic study revealed that the distinct 1 O 2 production under low‐energy light is attributed to the spatially locked structure and charge localization around active centers. These features enhance strong π–π stacking interaction, promote effective charge separation and transport properties, and ultimately facilitate the activation of O 2 to 1 O 2 . This study paves the way for the development of high‐performance COF photocatalysts for low‐energy light‐driven reactive oxygen species generation in advanced oxidation processes.