Shimoni Ran, Shi Zhuocheng, Binyamin Shahar, Yang Yang, Liberman Itamar, Ifraemov Raya, Mukhopadhyay Subhabrata, Zhang Liwu, Hod Idan
Department of Chemistry and Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva, 8410501, Israel.
Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science & Engineering, Fudan University, Shanghai, 200433, China.
Angew Chem Int Ed Engl. 2022 Aug 8;61(32):e202206085. doi: 10.1002/anie.202206085. Epub 2022 Jun 28.
Metal-organic frameworks (MOFs) are promising platforms for heterogeneous tethering of molecular CO reduction electrocatalysts. Yet, to further understand electrocatalytic MOF systems, one also needs to consider their capability to fine-tune the immediate chemical environment of the active site, and thus affect its overall catalytic operation. Here, we show that electrostatic secondary-sphere functionalities enable substantial improvement of CO -to-CO conversion activity and selectivity. In situ Raman analysis reveal that immobilization of pendent positively-charged groups adjacent to MOF-residing Fe-porphyrin catalysts, stabilize weakly-bound CO intermediates, allowing their rapid release as catalytic products. Also, by varying the electrolyte's ionic strength, systematic regulation of electrostatic field magnitude was achieved, resulting in essentially 100 % CO selectivity. Thus, this concept provides a sensitive molecular-handle that adjust heterogeneous electrocatalysis on demand.
金属有机框架材料（MOFs）是用于分子CO还原电催化剂非均相连接的有前景的平台。然而，为了进一步理解电催化MOF体系，人们还需要考虑它们微调活性位点紧邻化学环境的能力，从而影响其整体催化操作。在此，我们表明静电二级球功能能够显著提高CO到CO的转化活性和选择性。原位拉曼分析表明，在MOF负载的铁卟啉催化剂附近固定悬垂的带正电荷基团，可稳定弱结合的CO中间体，使其作为催化产物快速释放。此外，通过改变电解质的离子强度，实现了静电场强度的系统调节，从而实现了基本上100%的CO选择性。因此，这一概念提供了一种灵敏的分子手段，可按需调节非均相电催化。
