Enhancing the charge separation efficiency is highly effective strategy in improving the photocatalytic activity of covalent organic frameworks (COFs) which have the problems of low conductivity and difficult dissociation of excitons. In this work, we report the sevenfold increase in apparent quantum efficiency resulting from the use of a near-single layer COF (SLCOF) in photocatalytic hydrogen evolution compared with bulk COF. Detected by transient absorption spectroscopy characterization, 100% of photogenerated long-lived electrons in the near-SLCOF can be extracted and participate in the photocatalytic process. However, the electron extraction efficiency declined to only about 11% when the COFs were increased to eight layers, implying the difficulty of charge migration among COFs interlayers. The near-SLCOF was prepared by deposition of self-exfoliated COFs colloids on SiO₂, driven by their strong affinity. This work not only sheds light on the significant influence of COF layer thickness on the charge separation efficiency but also provides a new route to prepare and stabilize COF layers for practical applications.

提高电荷分离效率是提高共价有机骨架（COF）光催化活性的有效策略，共价有机骨架存在电导率低和激子难以解离的问题。在这项工作中，我们报告了与本体 COF 相比，在光催化析氢中使用近单层 COF (SLCOF) 导致表观量子效率增加了七倍。通过瞬态吸收光谱表征检测，近 SLCOF 中 100% 的光生长寿命电子可以被提取并参与光催化过程。然而，当 COFs 增加到 8 层时，电子提取效率下降到仅 11% 左右，这意味着 COFs 层间的电荷迁移困难。₂、在他们强烈的亲和力的驱使下。这项工作不仅阐明了 COF 层厚度对电荷分离效率的显着影响，而且为实际应用中制备和稳定 COF 层提供了新途径。