Heptazine‐Based D–A Polymers for Photocatalytic 2,4‐Dichlorophenol Degradation via Enhanced Exciton Dissociation

The exciton binding energy ( E _b ) is recognized as a pivotal parameter governing charge separation in polymeric photocatalysts. Reducing E _b in polymers enhances carrier generation, thereby boosting photocatalytic activity. Rationally constructing donor–acceptor (D–A) architectures in heptazine‐based polymers offers an effective strategy to overcome intrinsic excitonic limitations. In this work, CN _x ( x = 0.015, 0.025, 0.05) materials with intramolecular D–A configurations were developed by integrating electron‐donating units with heptazine acceptor motifs. The optimized material CN _0.025 exhibits a 29% reduction in E _b (97 → 69 meV) and extended visible‐light absorption, attributable to enhanced π‐conjugation and modulated electronic structures. Remarkably, under visible‐light irradiation, CN _0.025 achieves 97.7% degradation of 2,4‐dichlorophenol (10 ppm) within 50 min. Moreover, CN _x exhibits a 29.8‐fold higher CO yield than pure g‐C ₃ N ₄ in photocatalytic CO ₂ reduction. Electrochemical photocurrent measurements reveal a remarkable enhancement in the photocurrent response of CN _0.025 relative to g‐C ₃ N ₄ , which suggests more efficient exciton dissociation and increased carrier availability at the catalytic surface for subsequent redox reactions. This work establishes a paradigm for exciton dissociation in polymeric photocatalysts through engineered D–A nanoarchitectures.