Efficient Electrochemical Hydrogenation of Nitroaromatics into Arylamines on a CuCo₂O₄ Spinel Cathode in an Alkaline Electrolyte

Abstract

Establishing an efficient hydrogenation strategy, especially with the use of water as a clean and safe hydrogen source to synthesize aromatic amines is of significance in the production of various fine chemicals. Herein, a nickel foam (NF)-supported CuCo2O4 spinel was synthesized via a two-step urea-assisted hydrothermal treatment and calcination process, which further generated Cu active sites during the electrocatalysis process. When used as the cathode for p-nitrophenol hydrogenation into p-aminophenol, conversion and selectivity over CuCo2O4/NF were up to 95.8 and 97.2%, respectively, all of which were significantly higher than other MCo2O4/NF (Mn, Fe, Co, and Zn) spinel materials. The Faraday efficiency remains high at 89.0% at a relatively large current density of 240 mA cm–2, which is beneficial for the scale-up for industrialization. Additionally, good yields were also obtained in the hydrogenation of a series of other substituted nitroaromatics over the CuCo2O4/NF cathode, with fragile functional groups being well protected during cathodic reactions.