南京工业大学周瑜团队报道了共价有机框架稳定的单一CoN₄Cl₂位点促进光催化CO₂还原成可调合成气。相关研究成果发表在2024年8月28日出版的《德国应用化学》。

太阳能二氧化碳（CO₂）还原为生产可持续化学品和燃料提供了一种有吸引力的替代方案。然而，由于电荷的快速复合和表面CO₂的缓慢减少，构建高活性的光催化剂具有挑战性。

该文中，研究人员通过将Co物种负载到含2,2'-联吡啶和三嗪的共价有机框架（COF）中，在可见光照射下将CO₂转化为合成气，制备了一种独特的Co-N₄Cl₂单位点。由此产生的最优催化剂TPy-COF-Co实现了426 mmol g^-1 h^-1的创纪录的Co生产率，分别与前所未有的2095和1607 h^-1的周转数（TON）和周转频率（TOF）相关。

该催化剂还表现出良好的回收性能和可广泛调节的合成气产量（CO/H₂比：1.8:1-1:16）。包括操作同步辐射X射线吸收精细结构（XAFS）光谱、原位衰减全反射表面增强红外吸收光谱（ATR-SEIRAS）和理论计算在内的系统研究表明，三嗪基COF框架促进了电荷向单个Co-N₄Cl₂位点的转移，通过降低*COOH产生的能垒，促进了CO₂的转化，从而大大促进了CO₂活化。

该项工作强调了COF衍生的单原子催化剂的分子调控，在提高CO₂光还原效率方面的巨大潜力。

附：英文原文

Title: Covalent Organic Framework Stabilized Single CoN4Cl2 Site Boosts Photocatalytic CO2 Reduction into Tunable Syngas

Author: Ping Fu, Cailing Chen, Chao Wu, Biao Meng, Qihong Yue, Tao Chen, Wen Yin, Xiao Chi, Xiaojiang Yu, Ruiting Li, Yao Wang, Yifan Zhang, Wen Luo, Xiaoling Liu, Yu Han, Jun Wang, Shibo Xi, Yu Zhou

Issue&Volume: 2024-08-28

Abstract: Solar carbon dioxide (CO2) reduction provides an attractive alternative to producing sustainable chemicals and fuel. However, the construction of a highly active photocatalyst was challenging because of the rapid charge recombination and sluggish surface CO2 reduction.  Herein, a unique Co-N4Cl2 single site was fabricated by loading Co species into the 2,2'-bipyridine and triazine-containing covalent organic framework (COF) for CO2 conversion into syngas under visible light irradiation. The resulting champion catalyst TPy-COF-Co enabled a record-high CO production rate of 426 mmol g-1 h-1, associated with the unprecedented turnover number (TON) and turnover frequency (TOF) of 2095 and 1607 h1, respectively. The catalyst also exhibited favorable recycling performance and widely adjustable syngas production (CO/H2 ratio: 1.8:1-1:16). A systematical investigation including operando synchrotron X-ray absorption fine structure (XAFS) spectroscopy, in-situ attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS), and theoretical calculation indicated that the triazine-based COF framework promoted the charge transfer towards the single Co-N4Cl2 sites that greatly promoted the CO2 activation by lowering the energy barrier of *COOH generation, facilitating the CO2 transformation. This work highlights the great potential of the molecular regulation of COF-derived single-atom catalysts to boost CO2 photoreduction efficiency.

DOI: 10.1002/anie.202415202

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202415202