La doped-Fe(MoO) with the synergistic effect between Fe/Fe cycling and oxygen vacancies enhances the electrocatalytic synthesizing NH.

The electrocatalytic nitrogen reduction reaction (NRR) is a crucial process in addressing energy shortages and environmental concerns by synthesizing the NH. However, the difficulty of N activation and fewer NRR active sites limit the application of NRR. Therefore, the NRR performance can be improved by rapid electron transport paths to participate in multi-electron reactions and N activation. Doping with transition metal element is a viable strategy to provide electrons and electronic channels in the NRR. This study focuses on the synthesis of Fe(MoO) (FeMo) and x%La-doped FeMo (x = 3, 5, 7, and 10) using the hydrothermal method. La-doping creates electron transport channels Fe-O-Fe and oxygen vacancies, achieving an equal molar ratio of Fe/Fe. This strategy enables the super-exchange in Fe-O-Fe, and then enhances electron transport speed for a rapid hydrogenation reaction. Therefore, the synergistic effect of Fe/Fe cycling and oxygen vacancies improves the NRR performance. Notably, 5%La-FeMo demonstrates the superior NRR performance (NH yield rate: 29.6 μg h mg, Faradaic efficiency: 5.8%) at -0.8 V (vs. RHE). This work analyzes the influence of the catalyst electronic environment on the NRR performance based on the effect on different valence states of ions on electron transport.