Photocatalytic conversion of CO₂ into hydrocarbon fuels is an ideal technology of mitigating greenhouse effect caused by excessive emission of CO₂. However, the high recombination rate of electron-hole pairs and limited charge carriers transport speed constrained the catalytic performance of many semiconductor catalysts. In this contribution, a series of carbon nitride (g-CN) samples with intramolecular donor-acceptor (D-A) system were successfully prepared by introducing organic donor into their structures. Characterization results confirmed that carbazole was successful connected to the structure of g-CN via chemical bond. The formation of intramolecular D-A system greatly enlarged the light response region of g-CN-xDbc. In addition, a new charge transfer transition mode was formed in g-CN-0.01Dbc due to the incorporation carbazole, which enable it to use light with energy lower than the intrinsic absorption of g-CN. Meanwhile, the D-A structure led to the spatial separation of electrons and holes in g-CN-xDbc and significantly decreased the recombination rate of electron-hole pairs. The g-CN-0.01Dbc presented the best catalytic performance and the CO evolution rate was 9.6 times higher than that of g-CN. Moreover, the reaction was performed in water without any additive, which made it green and sustainable. DFT simulation confirmed the D-A structure and charge carrier migration direction in the prepared samples.

将CO ₂光催化转化为碳氢化合物燃料是缓解因过度排放CO ₂引起的温室效应的理想技术。然而，电子-空穴对的高复合率和有限的载流子传输速度限制了许多半导体催化剂的催化性能。在此贡献中，通过将有机供体引入结构中，成功制备了一系列带有分子内供体-受体（DA）系统的氮化碳（g-CN）样品。表征结果证实咔唑通过化学键成功连接到g-CN的结构。分子内DA系统的形成大大扩大了g-CN-xDbc的光响应区域。此外，由于咔唑的引入，在g-CN-0.01Dbc中形成了新的电荷转移跃迁模式，这使其能够使用能量低于g-CN固有吸收率的光。同时，DA结构导致g-CN-xDbc中电子和空穴的空间分离，并显着降低了电子-空穴对的复合率。g-CN-0.01Dbc表现出最好的催化性能，CO释放速率比g-CN高9.6倍。而且，该反应在没有任何添加剂的水中进行，这使其绿色且可持续。DFT模拟证实了所制备样品中的DA结构和电荷载流子迁移方向。