Electrochemical synthesis of formamide by C–N coupling with amine and CO2 with a high faradaic efficiency of 37.5%

Abstract

N,N-Dimethylformamide (DMF) is a versatile chemical and universal solvent that is commonly synthesized from carbon monoxide and dimethylamine (DMA) under high temperature and pressure. However, this process leads to a large amount of carbon emissions. Herein, we propose an electrochemical strategy to directly convert carbon dioxide (CO₂) and DMA to DMF under ambient conditions. Loading palladium (Pd) onto copper (Cu) nanosheet catalysts with Cu vacancies (Pd/Cu-V_Cu) enabled the efficient synthesis of DMF, and the maximum yield and faradaic efficiency reached 385 mmol·h⁻¹·g_cat. ⁻¹ and 37.5%, respectively. In situ spectroscopy and density functional theory calculations indicated that Cu vacancies (Cu-V_Cu) promoted the adsorption of CO₂ on the catalyst surface, followed by its spontaneous coupling with DMA to form the C–N bond. Pd nanoparticles accelerated the electrochemical reduction of the intermediate ∗OCN(CH₃)₂OH to ∗OCHN(CH₃)₂OH, leading to highly efficient DMF electrosynthesis. This work paves the way for the synthesis of sustainable high-value organic nitrogen compounds from CO₂.