Theoretical study of tandem catalysts based on metal porphyrin-phthalocyanine two-dimensional carbon-rich conjugated frameworks for the co-reduction of NO3− and CO2 in the electrosynthesis of methylamine

Electrocatalytic NO3− and CO2 co-reduction to synthesize methylamine can remove NO3− and CO2 pollutants and produce valuable methylamine. However, the catalytic mechanism of electrocatalytic NO3− and CO2 co-reduction for the synthesis of methylamine is not sufficiently understood, and this research remains challenging. To supply the catalytic mechanism needed to create effective electrocatalysts, we systematically investigated the performance of metal-extended phthalocyanine and metalloporphyrin tandem catalysts to produce methylamine electrocatalytically through the co-reduction of NO3− and CO2 and found that the MoCo-Pc-Pt-N5Por COFs, MoNi-Pc-Pt-N5Por COFs, and MoRu-Pc-Pt-N5Por COFs were the most effective electrocatalysts. Also, we found that the metallic TM atoms in the catalysts with the NO3− and CO2 molecules with the coexistence of charge depletion and charge accumulation behavior as the activation mechanism of NO3− and CO2. This work offers a theoretical foundation for experimental research and opens up new possibilities for the rational design of effective electrocatalytic NO3− and CO2 co-reduction catalysts for synthesizing methylamine.