Electrochemical Reduction of N2 to NH3 at Low Potential by a Molecular Aluminum Complex

Chemistry. 2019 Jan 7;25(2):454-458. doi: 10.1002/chem.201804454. Epub 2018 Oct 30.

Abstract

Electrochemical generation of ammonia (NH3 ) from nitrogen (N2 ) using renewable electricity is a desirable alternative to current NH3 production methods, which consume roughly 1 % of the world's total energy use. The use of catalysts to manipulate the required electron and proton transfer reactions with low energy input is also a chemical challenge that requires development of fundamental reaction pathways. This work presents an approach to the electrochemical reduction of N2 into NH3 using a coordination complex of aluminum(III), which facilitates NH3 production at -1.16 V vs. SCE. Reactions performed under 15 N2 liberate 15 NH3 . Electron paramagnetic resonance spectroscopic characterization of a reduced intermediate and investigations of product inhibition, which limit the reaction to sub-stoichiometric, are also presented.

Keywords: N2 reduction; aluminium; ammonia; main group; redox-active ligands.