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

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.