The photocatalytic conversion of CO₂ into chemical fuels represents a promising approach for solving the future energy crisis. However, the construction of a photocatalyst simultaneously integrating a photosensitizer and molecular cocatalyst with intramolecular electron delivery is challenging. Herein, we designed covalent organic frameworks (COFs) with excellent extended conjugation and potential embedded redox active sites. The full -C = C- bridging in sp²c-COF_dpy creates and dredges the donor-acceptor channel for intramolecular electron delocalization and a cascade effect. Interestingly, CO₂ photoreduction can be carried out in water, and the optimized sp²c-COF_dpy-Co exhibits the highest activity and stability among COFs without noble metal involvement, achieving up to 17.93 mmol g⁻¹ CO with 81.4 % selectivity in a long-range reaction. Theoretical calculations and experimental data suggest that the structural advantages enable excitons to facilely reach single Co sites via the electron cascade, which provides a new concept in the nanoarchitecture of COFs for efficient CO₂ photoreduction.

将CO ₂光催化转化为化学燃料代表了一种解决未来能源危机的有前途的方法。然而，将光敏剂和分子助催化剂与分子内电子传递同时结合的光催化剂的构造是具有挑战性的。在这里，我们设计了具有出色的扩展共轭和潜在的嵌入式氧化还原活性位点的共价有机框架（COF）。在sp ² c-COF _dpy中的完整-C = C-桥联产生并疏通了分子内电子离域和级联效应的供体-受体通道。有趣的是，CO _2光还原可以在水中进行，并且优化的sp ² c-COF _dpy-Co在没有贵金属参与的COF中表现出最高的活性和稳定性，在远距离反应中获得高达17.93 mmol g ^-1的CO和81.4％的选择性。理论计算和实验数据表明，结构优势使激子可以通过电子级联轻松到达单个Co位点，这为COF的纳米体系结构提供了有效的CO _2光还原的新概念。