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End date: 2024 × Start date: 2020 × DDC: 540 × Version: publishedVersion × Subject: carbon dioxide ×

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    Electrocatalytic Reduction of CO2 to Acetic Acid by a Molecular Manganese Corrole Complex
    (Weinheim : Wiley-VCH, 2020) De, Ratnadip; Gonglach, Sabrina; Paul, Shounik; Haas, Michael; Sreejith, S.S.; Gerschel, Philipp; Apfel, Ulf-Peter; Vuong, Thanh Huyen; Rabeah, Jabor; Roy, Soumyajit; Schöfberger, Wolfgang
    The controlled electrochemical reduction of carbon dioxide to value added chemicals is an important strategy in terms of renewable energy technologies. Therefore, the development of efficient and stable catalysts in an aqueous environment is of great importance. In this context, we focused on synthesizing and studying a molecular MnIII-corrole complex, which is modified on the three meso-positions with polyethylene glycol moieties for direct and selective production of acetic acid from CO2. Electrochemical reduction of MnIII leads to an electroactive MnII species, which binds CO2 and stabilizes the reduced intermediates. This catalyst allows to electrochemically reduce CO2 to acetic acid in a moderate acidic aqueous medium (pH 6) with a selectivity of 63 % and a turn over frequency (TOF) of 8.25 h−1, when immobilized on a carbon paper (CP) electrode. In terms of high selectivity towards acetate, we propose the formation and reduction of an oxalate type intermediate, stabilized at the MnIII-corrole center. © 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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    Steering carbon dioxide reduction toward C–C coupling using copper electrodes modified with porous molecular films
    ([London] : Nature Publishing Group UK, 2023) Zhao, Siqi; Christensen, Oliver; Sun, Zhaozong; Liang, Hongqing; Bagger, Alexander; Torbensen, Kristian; Nazari, Pegah; Lauritsen, Jeppe Vang; Pedersen, Steen Uttrup; Rossmeisl, Jan; Daasbjerg, Kim
    Copper offers unique capability as catalyst for multicarbon compounds production in the electrochemical carbon dioxide reduction reaction. In lieu of conventional catalysis alloying with other elements, copper can be modified with organic molecules to regulate product distribution. Here, we systematically study to which extent the carbon dioxide reduction is affected by film thickness and porosity. On a polycrystalline copper electrode, immobilization of porous bipyridine-based films of varying thicknesses is shown to result in almost an order of magnitude enhancement of the intrinsic current density pertaining to ethylene formation while multicarbon products selectivity increases from 9.7 to 61.9%. In contrast, the total current density remains mostly unaffected by the modification once it is normalized with respect to the electrochemical active surface area. Supported by a microkinetic model, we propose that porous and thick films increase both local carbon monoxide partial pressure and the carbon monoxide surface coverage by retaining in situ generated carbon monoxide. This reroutes the reaction pathway toward multicarbon products by enhancing carbon–carbon coupling. Our study highlights the significance of customizing the molecular film structure to improve the selectivity of copper catalysts for carbon dioxide reduction reaction.