Isomerization Engineering of Carbazole-Based Conjugated Organic Polymers for Suppressed Charge Recombination to Boost H ₂ O ₂ Production

Due to the advantages of zero emissions, convenience, and environmental friendliness, photocatalysis has emerged as a promising alternative to the anthraquinone process for efficient hydrogen peroxide (H 2 O 2 ) generation. As a promising photocatalyst, the conjugated organic polymers (COPs) have garnered significant attention in this field; however, the intrinsically weak oxygen adsorption ability and unavoidable charge recombination often hinder their photocatalytic performance. In this study, we proposed an isomerization strategy by precisely controlling the position of the linking segment. This strategy can preserve the electron donor–acceptor connectivity and the same elemental composition while effectively modulating the electronic structure and optimizing photocatalytic kinetics; thereby, the molecular planarity, O 2 adsorption behavior, charge distribution, and charge-transfer characteristics can all be regulated. The prepared naphthalimide- and carbazole-based COPs showed good H 2 O 2 production performance, increasing from 1.97 to 3.27 mmol g –1 h –1 by regulating the isomerization sites. This remarkable enhancement is attributed to the improved adsorption capability of aqueous O 2 and the altered intrinsic electronic environment, which collectively facilitate photogenerated charge transport. In the presence of a hole scavenger, the performance was further enhanced to 6.09 mmol g –1 h –1 . Our findings highlight the essential role of isomerization engineering in bridging molecular structure, offering a promising strategy for the development of highly efficient photocatalysts for sustainable H 2 O 2 production.