In the development of two-dimension (2D) materials, constructing orderly layer-by-layered heterostructure has been a formidable challenge for a long time. In this work, a convenient nitriding-pretreatment route has been applied to engineer the C vacancy defects in Ti₃C₂T_x MXene, which often results in the structural instability. Based on the above defect engineering, the 2D skeleton is maintained in the following Ti₃C₂T_x oxidation for the formation of TiO₂ and carbon layers. Successfully, a “from 2D to 2D” structure and functional transformation is realized and TiO₂ nanoplates are in-situ grown between carbon layers, which greatly boost photogenerated carrier’s separation and electron’s transmission. As a result, this TiO₂/C superstructure exhibits an efficient photocatalytic ability in water-splitting process under visible light without any cocatalyst (87.2 μmol g⁻¹ h⁻¹, 28.1 times of disordered TiO₂/C sample). The defect engineering for MXene provides a new strategy for the highly orderly layer-by-layer superstructure.

在二维（2D）材料的开发中，长期以来，构造有序的逐层异质结构一直是一个艰巨的挑战。在这项工作中，已经采用了方便的氮化预处理途径来工程化Ti ₃ C ₂ T _x MXene中的C空位缺陷，这通常会导致结构不稳定。基于上述缺陷工程，在随后的Ti ₃ C ₂ T _x氧化中保持2D骨架，以形成TiO ₂和碳层。成功地实现了“从2D到2D”的结构和功能转换，并且TiO ₂纳米板原位生长在碳层之间，极大地促进了光生载流子的分离和电子的传输。结果，该TiO ₂ / C超结构在无助催化剂的情况下在可见光下的水分解过程中显示出有效的光催化能力（87.2μmolg ^-1 h ^-1，是无序TiO ₂ / C样品的28.1倍）。MXene的缺陷工程为高度有序的逐层上层结构提供了新的策略。