Lithium-mediated electrochemical reduction of high pressure N2 to NH3

Lithium-mediated electrochemical reduction of N2 to NH3 was achieved. NH3 was formed with significant current efficiency (up to 8%) by the electrolysis of a solution of LiClO4 (0.2 M) + ethanol (0.18 M) in tetrahydrofuran under an atmospheric pressure of N2. The current efficiency for the NH3 formation increased with the N2 pressure, and quite a high current efficiency (59%) was obtained by carrying out the electrolysis under 50 atm of N2. The NH3 formation efficiency depended strongly on the kind and the amount of proton source (alcohol, carboxylic acid, and water) added to the electrolysis medium, as well as on the electrode material. NH3 was even formed (3.7% current efficiency) when air was used as a source of N2.