Photocatalytic carbon dioxide (CO₂) reduction technology using solar energy can convert carbon dioxide into fuels and chemicals, and is one of the most effective strategies to mitigate the energy crisis and greenhouse effect. In recent years, covalent organic frameworks (COFs) have flourished due to their unique advantages and have received extensive attention in the field of photocatalytic reduction of CO₂. Here, we use the pre-designability of COFs to preserve the aldehyde group at the end of the COF skeleton by the motif strategy, while ensuring its excellent photosensitivity. This facilitates further assembly with amino-terminated g-C₃N₄ through covalent bonding, resulting in composite catalysts (COF@g-C₃N₄). This COF@g-C₃N₄ material can take g-C₃N₄ as the active center to undertake the main catalytic reaction function, COF as the photosensitive center to absorb light energy and generate photogenerated carriers, and covalent bonds as electron transport bridges, effectively facilitating the transfer of electrons. These three components operate independently yet synergistically to accomplish the photocatalytic CO₂ reduction reaction. In addition, by integrating theoretical calculations with experimental results, the electron transfer and reaction mechanism in the photocatalytic process of COF@g-C₃N₄ were thoroughly explored, and a rational photocatalytic process was proposed. This multi-center metal-free catalyst, COF@g-C₃N₄, not only exhibits good photocatalytic performance but also is more economical and environmentally friendly, which is worthy of attention.

中文翻译：

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一种与共价键组装的多中心无金属 COF@g-C3N4 催化剂，用于光催化 CO2 还原


利用太阳能的光催化二氧化碳 （CO₂） 还原技术可以将二氧化碳转化为燃料和化学品，是缓解能源危机和温室效应的最有效策略之一。近年来，共价有机框架 （COFs） 因其独特的优势而蓬勃发展，并在光催化还原 CO₂ 领域受到广泛关注。在这里，我们利用 COF 的预设计性，通过基序策略保留 COF 骨架末端的醛基，同时确保其出色的光敏性。这有利于通过共价键与氨基封端的 g-C₃N₄ 进一步组装，从而产生复合催化剂 （COF@g-C₃N₄）。这种 COF@g-C₃N₄ 材料可以以 g-C₃N₄ 为活性中心承担主要的催化反应功能，以 COF 为感光中心吸收光能并产生光生载流子，共价键作为电子传递桥，有效促进电子的转移。这三种组分独立但协同作用，以完成光催化 CO₂ 还原反应。此外，通过将理论计算与实验结果相结合，深入探究了 COF@g-C₃N₄ 光催化过程中的电子转移和反应机理，提出了合理的光催化过程。 这种多中心无金属催化剂 COF@g-C₃N₄ 不仅表现出良好的光催化性能，而且更加经济环保，值得关注。