Control and insight into active sites and charge transport behaviors are challenging topics for fabricating heterojunction photocatalyst and investigating photocatalytic reaction mechanism. Herein, the 2D/2D Ti₃C₂/g-C₃N₄ heterojunctions are fabricated in the semi-closed system, in which the interaction at heterointerfaces is enhanced to improve the stability. Furthermore, 2D Ti₃C₂ not only serves as electron harvester to propel the directed transfer of photogenerated electrons from 2D g-C₃N₄ to 2D Ti₃C₂ and the high-efficiency separation of charge carriers, but also creates the boundary edge active sites on its surface, thus enhancing the photocatalytic performance. The photocatalytic reaction mechanism for H₂ production and degrading tetracycline hydrochloride (TH-HCl) are also revealed in detail, including identification of active sites, transport behaviors of charge carriers, generation of active species and intermediates, reaction ways, etc. This work provides a significant reference for the design, fabrication and mechanism insight of 2D/2D heterojunction materials in the photocatalytic application.

控制和深入了解活性位点和电荷传输行为是制造异质结光催化剂和研究光催化反应机理的具有挑战性的主题。在此，在半封闭系统中制备了2D / 2D Ti ₃ C ₂ / gC ₃ N ₄异质结，其中异质界面处的相互作用得到增强，从而提高了稳定性。此外，2D Ti ₃ C ₂不仅充当电子收集器，以推动光生电子从2D gC ₃ N ₄到2D Ti ₃ C ₂的定向转移。以及电荷载流子的高效分离，还可以在其表面上产生边界边缘活性位，从而提高了光催化性能。还详细揭示了H ₂产生和降解四环素盐酸盐（TH-HCl）的光催化反应机理，包括活性位点的识别，电荷载体的传输行为，活性物种和中间体的生成，反应方式等。这项工作提供了对于光催化应用中2D / 2D异质结材料的设计，制造和机理研究具有重要参考意义。