McKee Morgan, Kutter Maximilian, Wu Yue, Williams Hannah, Vaudreuil Marc-Antoine, Carta Mariolino, Yadav Ashok Kumar, Singh Harishchandra, Masson Jean-François, Lentz Dieter, Kühnel Moritz F, Kornienko Nikolay
Institute of Inorganic Chemistry, University of Bonn, Bonn, Germany.
Department of Chemistry, Université de Montréal, Montréal, Québec, Canada.
Nat Chem. 2025 Jan;17(1):92-100. doi: 10.1038/s41557-024-01650-6. Epub 2024 Oct 4.
Molecular catalysts offer tunable active and peripheral sites, rendering them ideal model systems to explore fundamental concepts in catalysis. However, hydrophobic designs are often regarded as detrimental for dissolution in aqueous electrolytes. Here we show that established cobalt terpyridine catalysts modified with hydrophobic perfluorinated alkyl side chains can assemble at the gas-liquid-solid interfaces on a gas diffusion electrode. We find that the self-assembly of these perfluorinated units on the electrode surface results in a catalytic system selective for electrochemical CO reduction to CH, whereas every other cobalt terpyridine catalyst reported previously was only selective for CO or formate. Mechanistic investigations suggest that the pyridine units function as proton shuttles that deliver protons to the dynamic hydrophobic pocket in which CO reduction takes place. Finally, integration with fluorinated carbon nanotubes as a hydrophobic conductive scaffold leads to a Faradaic efficiency for CH production above 80% at rates above 10 mA cm-impressive activities for a molecular electrocatalytic system.
分子催化剂具有可调节的活性位点和外围位点，使其成为探索催化基本概念的理想模型体系。然而，疏水设计通常被认为不利于在水性电解质中溶解。在此，我们表明，用疏水性全氟烷基侧链修饰的已确立的钴联吡啶催化剂可以在气体扩散电极的气-液-固界面处组装。我们发现，这些全氟单元在电极表面的自组装导致了一种对电化学CO还原为CH具有选择性的催化体系，而此前报道的其他钴联吡啶催化剂仅对CO或甲酸盐具有选择性。机理研究表明，吡啶单元起到质子穿梭体的作用，将质子传递到发生CO还原的动态疏水口袋中。最后，与作为疏水导电支架的氟化碳纳米管集成，在高于10 mA cm的速率下，CH生成的法拉第效率超过80%——这对于分子电催化体系来说是令人印象深刻的活性。
