The rapid recombination rate of photogenerated carriers in TiO₂ has been limiting the photocatalytic performance. Herein, TiO₂ thin flakes modified by g-C₃N₄ quantum dots (g-C₃N₄ QDs) were fabricated successfully through a facile thermal treatment of restacked single-layer nanosheets of Ti_1.73O₄^1.07- in the presence of urea as a source of g-C₃N₄ QDs. Characterizations showed that g-C₃N₄ QDs with a size of ∼10 nm were homogeneously deposited on the surface of TiO₂ thin flakes. Quenching experiments of •OH radicals and the detection of radicals by EPR certified the direct Z-scheme heterojunctions between g-C₃N₄ QDs and TiO₂ flakes. The TiO₂ nanoflakes/g-C₃N₄ QDs hybrid exhibited excellent activity for the photocatalytic hydrogen evolution from a methanol solution and the degradation of RhB due to the enhanced charge separation efficiency and improved light absorption in the direct Z-scheme heterojunctions. This study demonstrates that the rational design of heterojunction is effective for attaining the superior photocatalytic performance.

TiO ₂中光生载流子的快速复合率限制了光催化性能。在此，在尿素作为来源的情况下，通过对重新^堆叠的 Ti _1.73 O ₄ ^1.07-单层纳米片进行简单的热处理，成功制备了由 gC ₃ N ₄量子点（gC ₃ N ₄ QD）改性的TiO ₂薄片gC ₃ N ₄ QD。表征表明，尺寸约为 10 nm 的gC ₃ N ₄ QDs 均匀沉积在 TiO ₂表面薄片。•OH 自由基的淬灭实验和 EPR 自由基检测证明了 gC ₃ N ₄量子点和 TiO ₂薄片之间的直接 Z 型异质结。TiO ₂纳米薄片/gC ₃ N ₄ QDs 杂化物由于提高的电荷分离效率和改善的直接 Z 型异质结中的光吸收而对甲醇溶液的光催化析氢和 RhB 的降解表现出优异的活性。该研究表明，异质结的合理设计对于获得优异的光催化性能是有效的。