Theoretical study on the synthesis of methylamine by electrocatalytic CO2 and NO3− co-reduction

Abstract

Electrocatalytic co-reduction of carbon dioxide (CO₂) and nitrate (NO₃⁻) to methylamine (MMA) has been recognized as a promising pathway for the electrochemical synthesis of MMA. However, the catalytic mechanism of electrosynthesis of methylamine is still unclear, making this study challenging. In this paper, the performance of phthalocyanine-porphyrin tandem catalysts for the electrocatalytic synthesis of methylamine by the co-reduction of NO₃⁻ and CO₂ was studied by Density Functional Theory (DFT). The FeZr-Pc-Co–N₃O–Por COFs catalyst was found to have efficient performance for the electrosynthesis of methylamine with a limiting potential of −0.56 eV. Meanwhile, we found that the high catalytic activity of FeZr-Pc•Co–N₃O-Por COFs catalysts originates from the “donate-back” mechanism of electrons between the active sites of the catalyst substrate and the reactants CO₂ and NO₃⁻ molecules. The theoretical understanding of electrocatalytic NO₃⁻ and CO₂ co-reduction for methylamine synthesis over tandem catalysts is provided by this paper. It creates new opportunities for the logical development of effective catalysts for methylamine electrosynthesis.