Single‐Step Synthesis of Fe−Fe3O4 Catalyst for Highly Efficient and Selective Electrochemical Nitrogen Reduction

Abstract Nitrogen reduction electrocatalysts are highly attractive for catalytic science. However, most electrocatalysts are limited by their low faradaic efficiency, poor ammonia yield, and tedious and costly catalyst synthesis process. In this work, Fe‐based oxide composite nanoparticles with steady chemical states are prepared by a single‐step green procedure under ambient conditions. The resulting Fe−Fe3O4 demonstrates remarkable activity and selectivity for nitrogen reduction reaction (NRR) with the highest faradaic efficiency of 53.2±1.8 % and NH3 yield rate of 24.6±0.8 μg h−1 mgcat.−1 at −0.4 V (vs. RHE) in 0.1 m Na2SO4 electrolyte. Characterization experiments and theoretical calculation reveal that Fe−Fe3O4 exhibits significantly enhanced charge transfer capability and suppresses the competitive HER process.