Acetamide Electrosynthesis from CO2 and Nitrite in Water

Abstract

Renewable electricity driven electrocatalytic CO₂ reduction reaction (CO₂ RR) is a promising solution to carbon neutralization, which mainly generate simple carbon products. It is of great importance to produce more valuable C-N chemicals from CO₂ and nitrogen species. However, it is challenging to co-reduce CO₂ and NO₃ ^- /NO₂ ^- to generate aldoxime an important intermediate in the electrocatalytic C-N coupling process. Herein, we report the successful electrochemical conversion of CO₂ and NO₂ ^- to acetamide for the first time over copper catalysts under alkaline condition through a gas diffusion electrode. Operando spectroelectrochemical characterizations and DFT calculations, suggest acetaldehyde and hydroxylamine identified as key intermediates undergo a nucleophilic addition reaction to produce acetaldoxime, which is then dehydrated to acetonitrile and followed by hydrolysis to give acetamide under highly local alkaline environment and electric field. Moreover, the above mechanism was successfully extended to the formation of phenylacetamide. This study provides a new strategy to synthesize highly valued amides from CO₂ and wastewater.

Keywords: Acetamide; CO2; Copper; Electrocatalysis; Nitrite.