Gao Shuaiqi, Zhao Xiao, Zhang Qian, Guo Linlin, Li Zhiyong, Wang Huiyong, Zhang Suojiang, Wang Jianji
Key Laboratory of Green Chemical Media and Reactions (Ministry of Education), Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Chemistry and Chemical Engineering, Henan Normal University Xinxiang Henan 453007 P. R. China
Science and Technology on Aerospace Chemical Power Laboratory, Hubei Institute of Aerospace Chemotechnology Xiangyang 441003 P. R. China.
Chem Sci. 2024 Dec 3;16(3):1222-1232. doi: 10.1039/d4sc05999a. eCollection 2025 Jan 15.
The massive CO emissions from continuous increases in fossil fuel consumption have caused disastrous environmental and ecological crises. Covalent organic frameworks (COFs) hold the potential to convert CO and water into value-added chemicals and O to mitigate this crisis. However, their activity and selectivity are very low under conditions close to natural photosynthesis. In this work, inspired by the photosynthesis process in natural leaves, we successfully anchored atomically dispersed Fe sites into interlayers of the photoactive triazine-based COF (Fe-COF) membrane to serve as a mimic metalloenzyme for the first time. It is found that under gas-solid conditions and no addition of any photosensitizer and sacrificial reagent, the highly crystalline Fe-COF membrane shows a record high CO photoreduction performance with a CO production of 3972 μmol g in a 4 h reaction, ∼100% selectivity of CO, and excellent cycling stability (at least 10 cycles). In such a remarkable photocatalytic CO conversion, the atomically dispersed Fe sites with high catalytic activity significantly reduce the formation energy barrier of key *CO and *COOH intermediates, the high-density triazine moieties supply more electrons to the iron catalytic center to promote CO reduction, and the homogeneous COF membrane greatly improves the electron/mass transport. Thus, this work opens a new window for the design of highly efficient photocatalysts and provides new insights into their structure-activity relationship in CO photocatalytic reduction.
化石燃料消耗的持续增加所产生的大量一氧化碳排放已引发了灾难性的环境和生态危机。共价有机框架（COFs）有潜力将一氧化碳和水转化为高附加值化学品及氧气，以缓解这一危机。然而，在接近自然光合作用的条件下，它们的活性和选择性非常低。在这项工作中，受天然叶片光合作用过程的启发，我们首次成功地将原子分散的铁位点锚定到光活性三嗪基COF（Fe-COF）膜的层间，以充当模拟金属酶。研究发现，在气固条件下且不添加任何光敏剂和牺牲试剂的情况下，高度结晶的Fe-COF膜显示出创纪录的高CO光还原性能，在4小时反应中CO产量为3972 μmol g，CO选择性约为100%，并且具有出色的循环稳定性（至少10个循环）。在如此显著的光催化CO转化中，具有高催化活性的原子分散铁位点显著降低了关键CO和COOH中间体的形成能垒，高密度的三嗪基团为铁催化中心提供更多电子以促进CO还原，而均匀的COF膜极大地改善了电子/质量传输。因此，这项工作为高效光催化剂的设计打开了一扇新窗口，并为其在CO光催化还原中的构效关系提供了新的见解。
