Study of the Electrochemical Reduction of Nitrogen on Iron–Molybdenum Compounds: A Theoretical and Experimental Approach to Understand the Mechanism

Ammonia (NH3) is an essential energy vector because it is an important source of hydrogen. Therefore, the generation of NH3 by means of green processes with renewable energies and without carbon dioxide emissions is relevant. In this work, the electrochemical nitrogen reduction reaction (NRR) to obtain ammonia is studied. The working electrode was a Fe–Mo mixture with its oxides on the surface. By means of characterization techniques such as FESEM, XPS, Raman Spectroscopy, and XRD, it was determined that the electroactive surface was a mixture of oxides, mainly hematite (α-Fe2O3) and molybdenum dioxide (MoO2). This electrode shows a geometric yield rate of 4.73 μg h–1 cm–2 with a faradaic efficiency (FE%) of 8.22% in 0.1 mol L–1 PBS. Using the SHINERS methodology supported by DFT calculations, hydrazine was identified as a reaction intermediate, indicating an alternative associative mechanism.