Surface-Active Hydrogen Coverage Engineering Enables Selective Electrochemical Hydrogenation of Nitrobenzene over a CoFe Catalyst

Abstract

Electrocatalytic hydrogenation of nitroarenes to aromatic amines is significant, but selectivity control remains challenging. Herein, a series of CoFe non-precious catalysts are prepared on carbon cloth via a facile constant-current deposition method. The optimal CoFe catalyst features a 3D honeycomb-like porous structure with a high electrochemically active surface area and enhanced mass transfer, delivering the highest cathodic current density and the most positive onset potential. At –1.2 V vs Hg/HgO, the nitrobenzene (NB) conversion approaches 100%, with the aniline (AN) yield and selectivity both exceeding 95%, demonstrating outstanding NB electroreduction (NBER) performance. In-situ Fourier-transform infrared spectroscopy (FTIR) confirms the reaction pathway NB → NSB → PHA → AN. Theoretical calculations reveal that CoFe optimizes the electronic structure to modulate the surface coverage of active hydrogen (*H) from water dissociation, thereby promoting the hydrogenation reaction while efficiently suppressing the competing hydrogen evolution reaction. Coupling this cathode with 5-hydroxymethylfurfural (HMF) oxidation to produce 2,5-furandicarboxylic acid (FDCA) gives a higher energy utilization efficiency and economic returns than the conventional system that coupled with the oxygen evolution reaction. This work demonstrates a promising strategy for upgrading both nitroaromatic and biomass-derived substrates via green electrosynthesis, offering a viable route toward the energy-efficient and economically attractive co-production of fine chemicals.