Introducing a donor–acceptor (D–A) unit is an effective approach to facilitate charge transfer in polymeric carbon nitride (PCN) and enhance photocatalytic performance. However, the introduction of hetero-molecules can lead to a decrease in crystallinity, limiting interlayer charge transfer and inhibiting further improvement. In this study, we constructed a novel D–A type carbon nitride with significantly higher crystallinity and a bi-directional charge transfer channel, which was achieved through 2,5-thiophenedicarboxylic acid (2,5-TDCA)-assisted self-assembly followed by KCl-templated calcination. The thiophene and cyano groups introduced serve as the electron donor and acceptor, respectively, enhancing in-plane electron delocalization. Additionally, introduced potassium ions are intercalated among the adjacent layers of carbon nitride, creating an interlayer charge transfer channel. Moreover, the highly ordered structure and improved crystallinity further facilitate charge transfer. As a result, the as-prepared photocatalyst exhibits superior photocatalytic hydrogen evolution (PHE) activity of 7.449 mmol h⁻¹ g⁻¹, which is 6.03 times higher than that of pure carbon nitride. The strategy of developing crystalline D–A-structured carbon nitride with controlled in-plane and interlayer charge transfer opens new avenues for the design of carbon nitride with enhanced properties for PHE.

中文翻译：

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高结晶氮化碳中的双向电荷转移通道可实现卓越的光催化析氢

引入供体-受体（D-A）单元是促进聚合氮化碳（PCN）中电荷转移和增强光催化性能的有效方法。然而，异质分子的引入会导致结晶度降低，限制层间电荷转移并抑制进一步的改进。在这项研究中，我们构建了一种新型的D-A型氮化碳，具有明显更高的结晶度和双向电荷转移通道，这是通过2,5-噻吩二甲酸（2,5-TDCA）辅助自组装实现的通过 KCl 模板煅烧。引入的噻吩和氰基分别作为电子供体和受体，增强面内电子离域。此外，引入的钾离子插入相邻的氮化碳层之间，形成层间电荷转移通道。此外，高度有序的结构和改善的结晶度进一步促进电荷转移。结果，所制备的光催化剂表现出优异的光催化析氢（PHE）活性，为7.449 mmol h ^-1 g ^-1，比纯氮化碳高6.03倍。开发具有受控面内和层间电荷转移的晶体 D-A 结构氮化碳的策略为设计具有增强 PHE 性能的氮化碳开辟了新途径。