华南师范大学兰亚乾团队开发出了用于人工光合低浓度CO₂还原的基于双金属盐的共价有机框架。相关研究成果于2024年10月7日发表在《德国应用化学》。

利用人工光合技术直接转化烟气中的二氧化碳，是一种有前景的二氧化碳资源利用绿色方法。然而，由于光催化剂在低浓度的CO₂气氛中的活性降低，实现有效减少烟气中的CO₂仍然是一个巨大的挑战。

该文中，研究人员设计并合成了一系列基于双金属Salen的共价有机框架（MM-Salen-COFs，M:Zn，Ni，Cu），用于人工光合低浓度CO₂还原，并证实了它们与单金属M-Salen-COFs相比的优势。结果表明，在纯CO₂气氛下，具有双Zn位点的ZnZn-Salen COF表现出显著的，可见光驱动CO₂到CO的转化率为150.9μmol g^-1 h^-1，比单金属Zn-Salen-COF高出约6倍。

值得注意的是，在模拟烟气条件（15%CO₂）的低浓度CO₂气氛下，双金属Zn Zn-Salen COF仍然显示出102.1μmol g^-1 h^-1的有效CO₂转化活性，这在相同反应条件下COF和MOF基光催化剂中是创纪录的高活性。进一步的研究和理论计算表明，ZnZn-Salen COF中相邻双金属位点之间的协同效应促进了低浓度CO₂的吸附和活化，从而降低了速率决定步骤的能量势垒。

附：英文原文

Title: Dual Metallosalen-based Covalent Organic Frameworks for Artificial Photosynthetic Diluted CO2 Reduction

Author: Hong Dong, Liang Fang, Ke-Xin Chen, Jian-Xin Wei, Jia-Xin Li, Xiu Qiao, Ya Wang, Feng-Ming Zhang, Ya-Qian Lan

Issue&Volume: 2024-10-07

Abstract: Directly converting CO2 in flue gas using artificial photosynthetic technology represents a promising green approach for CO2 resource utilization. However, it remains a great challenge to achieve efficient reduction of CO2 from flue gas due to the decreased activity of photocatalysts in diluted CO2 atmosphere. Herein, we designed and synthesized a series of dual metallosalen-based covalent organic frameworks (MM-Salen-COFs, M: Zn, Ni, Cu) for artificial photosynthetic diluted CO2 reduction and confirmed their advantage in comparison to that of single metal M-Salen-COFs. As a results, the ZnZn-Salen-COF with dual Zn sites exhibits a prominent visible-light-driven CO2-to-CO conversion rate of 150.9 μmol g1 h1 under pure CO2 atmosphere, which is ~6 times higher than that of single metal Zn-Salen-COF. Notably, the dual metal ZnZn-Salen-COF still displays efficient CO2 conversion activity of 102.1 μmol g1 h1 under diluted CO2 atmosphere from simulated flue gas conditions (15% CO2), which is a record high activity among COFs- and MOFs-based photocatalysts under the same reaction conditions. Further investigations and theoretical calculations suggest that the synergistic effect between the neighboring dual metal sites in the ZnZn-Salen-COF facilitates low concentration CO2 adsorption and activation, thereby lowering the energy barrier of the rate-determining step.

DOI: 10.1002/anie.202414287

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202414287