Donor–Acceptor Modification of Carbon Nitride for Enhanced Photocatalytic Hydrogen Evolution

The construction of conjugated copolymers with a donor–acceptor (D–A) system has emerged as a promising strategy for improving photocatalytic activity. Herein, a donor–acceptor modified carbon nitride (CN) conjugated copolymer is fabricated via facile thermal copolymerization of 2‐aminobenzimidazole (abIM) and urea. The experimental results demonstrate that the abIM units are successfully incorporated into the framework of CN and the main chemical structure of CN is still preserved. These abIM units can serve as electron acceptors, extending the π‐conjugated system and inducing the intramolecular charge transfer via an internal electric field. As a result, the construction of D–A structure not only improves the optical utilization efficiency but also facilitates the intramolecular migration of electrons and holes, leading to enhanced photocatalytic hydrogen evolution (2566 µmol g−1 h−1) as compared to pristine CN. This work provides a simple but effective method for preparing high‐performance carbon nitride photocatalysts. The donor–acceptor modification of carbon nitride (CN) is achieved via facial thermal copolymerization of 2‐aminobenzimidazole (abIM) and urea. An internal electric field is formed from CN to abIM due to the electron‐withdrawing inductive effect of abIM, promotes the spatial separation of electrons and holes. Such a CN‐based donor–acceptor copolymer exhibits excellent performance toward photocatalytic hydrogen evolution.