Geyla Dubed Bandomo - CO2 conversion with {Mn(CO)3Br} molecular sites into Covalent-Organic Frameworks

Durée : 00:25:19 -Réalisation : 15 juin 2021 -Mise en ligne : 15 juin 2021
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Effective large-scale CO2 conversion to fuels or value-added chemicals using renewable energies is critical to reduce our environmental impact [1]. To this end, better understanding of the CO2 mechanism is needed to develop efficient and selective catalysts that operates in water controlling H2 evolution. Covalent Organic Frameworks (COFs) are reticular materials, which can be used to combine the advantages of the well-defined molecular catalysts and the heterogeneous ones [2]. In this work, we present the first COF based on tricarbonyl Mn units, that by π-π stacking is attached to MWCNTs form electrocatalytic electrodes active for CO2 reduction in neutral water. The activity of these catalysts was evaluated by electrochemical techniques with stability in aqueous solution. With these materials we have integrated the classical Mn(bpy)CO3Br catalyst into a heterogeneous material which clearly enhances its catalytic activity (FE~50%) at low overpotentials (~450 mV) in pure water. COF/MWCNTs/Nafion leds higher faradaic efficiency than molecular system. The encapsulation of tricarbonyl Mn active sites with a reticular covalent organic structure plays an important role by favouring the electrocatalytic CO2 reduction over competitive H2 evolution reaction. The spectroelectrochemical studies evidence the formation of five-coordinate species in the catalytic cycle for CO formation.


[1]Alessandro Sinopoli, Nathan T. La Porte, Coord. Chem. Rev., 365, 2018 pp 60–74.[2]Lin S, O. M. Yaghi, Science, 349, 2015 pp 1208-1213.[3]B. Reuillard, E. Reisner, J. Am. Chem Soc., 169, 2017 pp 14425-14435.[4]James J. Walsh, Alexander J. Cowan, Phys. Chem., 20, 2018 pp 6811-6816.


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