Photocatalytic CO₂ reduction driven by sustainable solar energy is a highly desirable route to achieve carbon recycling, to which charge separation in photocatalysts holds the key. In this work, two-dimensional (2D) WO₃·H₂O nanosheets with rich oxygen vacancies (Vo-WO_x) were combined with 2D BiOCl nanosheets to form a 2D/2D Vo-WO_x/BiOCl S-scheme heterojunction by a self-assembly process. The 2D/2D stacked structure combined with the introduction of oxygen vacancies in Vo-WO_x could improve the light harvesting of the designed photocatalytic system. The dual transfer pathways in the S-scheme junction were induced by the fact that the photogenerated electrons on the conduction band and defect energy level of the Vo-WO_x transfer across the interface to combine with the BiOCl, leading to an improved kinetic process of photogenerated carriers. Moreover, the S-scheme configuration can retain a strong redox potential for satisfying the thermodynamic requirement of CO₂ reduction. As a result, the optimized 30Vo-WO_x/BiOCl composite can achieve the highest CO yield rate of 8.82 μmol h⁻¹ from CO₂ reduction without any sacrifice reagents, which was 4.69 and 3.08 times higher than that of pure BiOCl and WO₃/BiOCl without oxygen vacancy. This work provides a new view of defect engineering in S-scheme heterojunction for pursuing a highly efficient photocatalytic CO₂ reduction system.

由可持续太阳能驱动的光催化 CO _{2还原是实现碳循环的非常理想的途径，其中光催化剂中的电荷分离是关键。}在这项工作中，将具有丰富氧空位（Vo-WO _x ）的二维（2D）WO ₃ ·H _{2 O纳米片}与二维BiOCl纳米片结合形成二维/二维Vo-WO _x /BiOCl S型异质结。自组装过程。2D/2D 堆叠结构与 Vo-WO _{x中氧空位的引入相结合}可以改善设计的光催化系统的光收集。_{S型结中的双转移路径是由导带上的光生电子和Vo-WO x}的缺陷能级跨界面转移与BiOCl结合的事实引起的，从而导致改进的动力学过程光生载流子。此外，S方案配置可以保持很强的氧化还原电位，以满足CO ₂还原的热力学要求。因此，优化后的 30Vo-WO _x /BiOCl 复合材料可以从 CO _{2中获得最高的 8.82 μmol h} ^-1的 CO 产率。没有任何牺牲试剂的还原，分别是纯BiOCl和无氧空位的WO ₃ /BiOCl的4.69倍和3.08倍。这项工作为寻求高效光催化CO ₂还原系统的S型异质结缺陷工程提供了新的视角。