In this study, a newly-designed Z-scheme g-C₃N₄@ZnO heterostructure was synthesized by 3D ZnO controllable deposition on 2D g-C₃N₄ nanosheets using thermal atomic layer deposition. The activity of 2D/3D g-C₃N₄@ZnO was evaluated by photocatalytic degradation of cephalexin under simulated sunlight. Results showed that the g-C₃N₄@ZnO photocatalyst achieved 98.9% degradation and 72.8% mineralization of cephalexin within 60 min of illumination. This degradation process fitted to the pseudo first order dynamic model with reaction rate constant of 0.0735 min⁻¹, 5.4 and 8.1 times higher than that of pure g-C₃N₄ and ZnO, respectively. Consecutive degradation experiments revealed the excellent stability and recyclability of 2D/3D g-C₃N₄@ZnO photocatalyst. Mechanism exploration found the enhanced photocatalytic activity was mainly ascribed to the strong oxidizability of active species generated on Z-scheme g-C₃N₄@ZnO. Besides, the oxidative species, especially h⁺ and $·\text{OH}$played significant roles in the degradation process. Moreover, the degradation intermediates were identified through HPLC/MS/MS analysis and the possible pathway of cephalexin decomposition was proposed accordingly. The Z-scheme 2D/3D g-C₃N₄@ZnO was also proved effective for contaminants removal in real sewage. This study provided a new platform for controllable creation of Z-scheme photocatalysts with broad application prospects in contaminants remediation from aquatic environment under solar light.

在这项研究中，通过使用热原子层沉积在2D gC ₃ N ₄纳米片上进行3D ZnO可控沉积，合成了一种新设计的Z方案gC ₃ N ₄ @ZnO异质结构。2D / 3D gC ₃ N ₄ @ZnO的活性通过模拟模拟阳光下头孢氨苄的光催化降解来评估。结果表明，gC ₃ N ₄ @ZnO光催化剂在光照下60分钟内降解了98.9％的头孢氨苄和72.8％的矿化度。此嵌合用的0.0735分钟的反应速率常数的准一级动力学模型降解过程^-1，5.4和8.1比纯的GC倍分别为₃ N ₄和ZnO。连续降解实验表明2D / 3D gC ₃ N ₄ @ZnO光催化剂具有出色的稳定性和可回收性。机理探索发现，增强的光催化活性主要归因于Z方案gC ₃ N ₄ @ZnO上产生的活性物种的强氧化性。此外，氧化性物质，尤其是h ⁺和$·\text{哦}$在降解过程中发挥了重要作用。此外，通过HPLC / MS / MS分析鉴定了降解中间体，并据此提出了头孢氨苄分解的可能途径。Z方案2D / 3D gC ₃ N ₄ @ZnO也被证明对去除实际污水中的污染物有效。这项研究提供了一个可控的Z方案光催化剂创造的新平台，在光解水环境中的污染物方面具有广阔的应用前景。