Strong dipole-promoted N-O bond hydrogenolysis enables ampere-level electrosynthesis of methylamine
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The electrochemical hydrogenolysis of nitromethane (CH 3 NO 2 ) in water provides a sustainable route for accessing methylamine (CH 3 NH 2 ), one of the simplest alkyl amines but the most commonly used bulk chemical. However, ineffective activation of the unactivated N−O σ -bond of the N -methylhydroxylamine (CH 3 NHOH) intermediate results in a CH 3 NH 2 selectivity below 10%. Here, low-coordinated copper (LC-Cu) is designed to enable the conversion of electrochemical CH 3 NO 2 -to-CH 3 NH 2 with 99% selectivity and 97% Faradaic efficiency at a low potential. A strong dipole moment to CH 3 NHOH over LC-Cu induces strong adsorption and an obvious Raman shift of the N‒O σ -bond in CH 3 NHOH to the LC-Cu surface at lower potentials, thus promoting N‒O hydrogenolysis. The rate-determining step changes as the pH alters, resulting in a pH-relevant volcano trend of CH 3 NO 2 -to-CH 3 NH 2 . The ampere-level production of 1.5 mol of CH 3 NH 2 , easy purification, gram-scale synthesis of deuterated methylamine and drugs, and hydrogenolysis of other N‒O bonds demonstrate promising potential.