Ghatak Arnab, Shanker G Shiva, Pearlmutter Yanai, Fryder Adi, Shimoni Ran, Hod Idan
Department of Chemistry and Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel.
J Am Chem Soc. 2025 Jun 18;147(24):20329-20337. doi: 10.1021/jacs.5c00316. Epub 2025 Jun 3.
Electrocatalytic CO reduction into multielectron products is a promising approach for carbon capture and utilization. Recently, cobalt phthalocyanine (CoPc)-based molecular catalysts have shown potential competence toward electrochemical conversion of CO to methanol, a 6e/6H product. Yet, despite the recent advancements, CoPc's tendency to aggregate and the weak CO-intermediate binding generally limit its electrocatalytic activity and selectivity. Herein, we demonstrate that a metal-organic framework (MOF) could be used to construct a tandem electrocatalytic system via immobilization of 2 types of molecular catalysts (CoPc and Fe-porphyrin). Notably, the MOF-based tandem achieves a 3-fold increase in electrocatalytic CO-to-methanol activity and selectivity compared to a CoPc-only MOF-based catalyst (up to 18% methanol faradaic efficiency at 25 mA/cm). Additionally, operando spectroscopy and electrochemical analysis show that unlike typical tandem systems, the MOF-based tandem operates uniquely by using a reactive intermediate different from CO (i.e., formaldehyde). Hence, this proof-of-concept approach offers a new means to design molecular electrocatalytic schemes capable of driving complex proton-coupled electron transfer reactions.
电催化将CO还原为多电子产物是一种很有前景的碳捕获和利用方法。最近，基于钴酞菁（CoPc）的分子催化剂对CO电化学转化为甲醇（一种6e/6H产物）显示出潜在的能力。然而，尽管最近有进展，但CoPc的聚集倾向和较弱的CO-中间体结合通常限制了其电催化活性和选择性。在此，我们证明金属有机框架（MOF）可用于通过固定两种类型的分子催化剂（CoPc和铁卟啉）构建串联电催化体系。值得注意的是，与仅基于CoPc的MOF催化剂相比，基于MOF的串联体系在电催化CO制甲醇的活性和选择性方面提高了3倍（在25 mA/cm时甲醇法拉第效率高达18%）。此外，原位光谱和电化学分析表明，与典型的串联体系不同，基于MOF的串联体系通过使用不同于CO的反应中间体（即甲醛）独特地运行。因此，这种概念验证方法提供了一种新手段来设计能够驱动复杂质子耦合电子转移反应的分子电催化方案。
