FeMo–N nanosheet arrays supported on nickel foam for efficient electrocatalytic N2 reduction to NH3 under ambient conditions

Abstract

Transition metal nitrogenous complexes have been extensively studied for electrochemical synthesis of ammonia due to their great capabilities in adsorbing and activating nitrogen molecules; yet the improvement of their catalytic performance is still a big challenge. Herein, a series of novel bimetallic Fe, Mo–N nanosheet arrays (FeMo–N) supported on nickel foam were fabricated through a facile hydrothermal–pyrolysis method, which were used as electrocatalysts for the nitrogen reduction reaction (NRR). It was discovered that the catalyst Fe₁Mo₁–N exhibited a promising performance with a NH₃ yield rate of 46.64 μg mg⁻¹_cat. h⁻¹ and a faradaic efficiency (FE) of 1.12% at −0.8 V vs. RHE, which also demonstrated excellent selectivity and thermal stability. The specific two-dimensional nanosheet morphology of the catalyst was believed to be the major reason contributing to the prominent electrochemical performance. The XPS characterization and NH₃ yield study at different N contents in the M–N bond further revealed that FeMo–N species are the primary active centers for the NRR, and the N content forming the M–N bond is closely related to the catalytic activity.