It is highly desirable to explore functionalized polymer semiconductor/g-C₃N₄ heterojunction photocatalysts with the tight interfacial connection for promoting the photogenerated electron-hole pair separation, improving the hydrophilicity, extending the visible light response and achieving the efficient visible light-driven H₂ evolution. Herein, we synthesized novel poly[9,9-bis(3-ethyl phosphate propyl)fluorene-alt-benzothiadiazole] (PPFBT) with a phosphate ester on every repeating unit by the Suzuki polymerization and then fabricated PPFBT/hydroxylated g-C₃N₄ (PPFBT/CN-OH) heterojunctions via a surface hydroxyl-induced assembly process. The ratio-optimized 5PPFBT/CN-OH shows the hydrogen evolution activity of 2662.4 μmol·g⁻¹·h⁻¹, an 11.1-time enhancement compared to CN-OH. The improved photocatalytic activity is mainly attributed to the enhanced electron-hole pair separation due to the tight interfacial connection by hydrogen bond (P=O…H-O) and N…S interactions between PPFBT and CN-OH. It is verified that abundant phosphate ester groups of PPFBT improve the hydrophilicity and form coordination bonds with platinum (P=O:Pt) as a cocatalyst to facilitate water splitting for H₂ evolution. It is also confirmed that the enhanced electron-hole pair separation is mainly dependent on the excited high-energy level electron transfer from CN-OH to PPFBT. This work provides a rational molecular design strategy for constructing efficient functionalized polymer semiconductor/g-C₃N₄ heterojunctions for sunlight-driven H₂ evolution.

迫切需要探索具有紧密界面连接的功能化聚合物半导体/gC ₃ N ₄异质结光催化剂，以促进光生电子空穴对分离、提高亲水性、延长可见光响应并实现高效的可见光驱动H ₂进化。在此，我们通过铃木聚合合成了每个重复单元上都有磷酸酯的新型聚[9,9-双（3-乙基磷酸丙酯）芴-替代-苯并噻二唑]（PPFBT），然后制备了PPFBT/羟基化gC ₃ N ₄ (PPFBT/CN-OH)异质结通过表面羟基诱导的组装过程。比例优化的5PPFBT/CN-OH的析氢活性为2662.4 μmol·g ^-1 ·h ^-1 ，比CN-OH提高了11.1倍。光催化活性的提高主要归因于PPFBT和CN-OH之间氢键(P=O…HO)和N…S相互作用的紧密界面连接增强了电子-空穴对分离。经证实，PPFBT丰富的磷酸酯基团提高了亲水性，并与作为助催化剂的铂(P=O:Pt)形成配位键，以促进水分解产生H ₂ 。还证实增强的电子空穴对分离主要依赖于激发的高能级电子从CN-OH到PPFBT的转移。这项工作为构建高效的功能化聚合物半导体/gC ₃ N ₄异质结以实现阳光驱动的H ₂演化提供了合理的分子设计策略。