Strong dipole-promoted N–O bond hydrogenolysis enables ampere-level electrosynthesis of methylamine

Abstract

The electrochemical hydrogenolysis of nitromethane in water could provide a sustainable route for accessing methylamine, one of the simplest alkyl amines and most commonly used bulk chemicals. However, present efforts achieve only methylamine selectivities below 10% due to the ineffective N–O bond activation of the N-methylhydroxylamine intermediate. Here we design a copper electrocatalyst with abundant low-coordination sites to enable the conversion of nitromethane to methylamine with 99% selectivity and 97% Faradaic efficiency at a low potential. The low-coordination copper sites induce a large dipole moment upon N-methylhydroxylamine adsorption to promote N‒O hydrogenolysis. Altering the pH changes the rate-determining step, resulting in a pH-dependent volcano trend for methylamine production. We demonstrate ampere-level production of 1.5 mol of methylamine alongside easy product purification, gram-scale synthesis of deuterated methylamine and drugs, and hydrogenolysis of other N‒O bonds. This work offers a promising, general approach to alkyl N–O bond hydrogenolysis that could compete with traditional thermochemical routines.