Local Electronic Modulation in Pillararene‐Based Donor–Acceptor Conjugated Polymers for Selective Photocatalytic Oxygen Reduction

ABSTRACT Constructing donor–acceptor (D–A) architectures is a widely adopted strategy for modulating the global band structures of photocatalytic polymers. However, it remains challenging to apply this approach to precisely fine‐tune the local electronic environment of active sites to optimize elementary catalytic steps while preserving the overall conjugated network. In this work, pillararenes with electron‐rich cavities are introduced into D–A conjugated polymers to construct a new material named BTzAP[5], whose reaction mechanism in photocatalytic hydrogen peroxide synthesis is systematically investigated. The electron‐rich cavity of pillararene modulates adjacent imine nitrogen active sites via the extended π‐conjugated system, significantly increasing their electron density, oxygen adsorption, and activation capacities. The tailored structure promotes a rapid stepwise two‐electron ORR pathway of O 2 to H 2 O 2 , with minimal free superoxide accumulation, achieving a production rate of 4086 µmol g −1 h −1 . This work offers a new strategy for achieving synergistic optimization of overall electronic engineering and local design of active sites in D–A type conjugated polymers.