Covalent organic frameworks (COFs) are an emerging type of crystalline and porous photocatalysts for hydrogen evolution, however, the overall water splitting activity of COFs is rarely known. In this work, we firstly realized overall water splitting activity of β-ketoamine COFs by systematically engineering N-sites, architecture, and morphology. By in situ incorporating sub-nanometer platinum (Pt) nanoparticles co-catalyst into the pores of COFs nanosheets, both Pt@TpBpy-NS and Pt@TpBpy-2-NS show visible-light-driven overall water splitting activity, with the optimal H₂ and O₂ evolution activities of 9.9 and 4.8 μmol in 5 h for Pt@TpBpy-NS, respectively, and a maximum solar-to-hydrogen efficiency of 0.23%. The crucial factors affecting the activity including N-sites position, nano morphology, and co-catalyst distribution were systematically explored. Further mechanism investigation reveals the tiny diversity of N sites in COFs that induces great differences in electron transfer as well as reaction potential barriers.

共价有机骨架（COF）是一种新兴的用于析氢的晶体和多孔光催化剂，然而，COF 的总体水分解活性却鲜为人知。在这项工作中，我们首先通过系统地设计N位点、结构和形态来实现β-酮胺COF的整体水分解活性。通过将亚纳米铂（Pt）纳米颗粒助催化剂原位掺入COF纳米片的孔中，Pt@TpBpy-NS和Pt@TpBpy-2-NS均表现出可见光驱动的整体水分解活性，具有最佳的水分解活性。 Pt@TpBpy-NS在5小时内的H ₂和O ₂析出活性分别为9.9和4.8 μmol，最大太阳能制氢效率为0.23%。系统地探讨了影响活性的关键因素，包括N位点位置、纳米形态和助催化剂分布。进一步的机制研究揭示了COF中N位点的微小多样性，导致电子转移和反应势垒的巨大差异。