Electrosynthesis of oximes and amines from CO and nitrite with a cobalt phthalocyanine catalyst

Traditional synthesis of organonitrogen compounds often requires high temperatures and pressures, contributing to greenhouse gas emissions and relying on costly noble metal catalysts. Electrosynthesis powered by renewable energy presents a sustainable alternative for C–N coupling reactions, though challenges remain in selectivity and mechanistic understanding. Here, we demonstrate that a molecular cobalt phthalocyanine (CoPc) complex immobilized on multi-walled carbon nanotubes (MWCNTs) efficiently catalyzes the co-electroreduction of CO and nitrite (NO2⁻) to produce C–N coupling products with high selectivity. Our study reveals that formaldehyde (HCHO), generated from CO reduction, reacts with in situ-produced hydroxylamine (NH2OH) from nitrite reduction to form formaldoxime (CH2=NOH) and methylamine (CH3NH2), achieving a total Faradaic efficiency exceeding 50%. Operando spectroscopy confirmed NH2OH as a key intermediate driving selective C–N bond formation. Extending this approach, we synthesized oximes like acetaldoxime and cyclohexanone oxime with ~70% Faradaic efficiency. This work offers a promising sustainable route for synthesizing diverse nitrogen-containing compounds.