Oxygen Vacancy Engineering of Fe-Doped NiMoO 4 for Electrocatalytic N 2 Fixation to NH 3 .

Electrochemical nitrogen reduction reaction (NRR) is a promising method for ammonia synthesis under ambient conditions. However, the NRR performance is limited to an extremely strong N≡N bond in N 2 and the competing hydrogen evolution reaction. Introducing oxygen vacancies (OVs) has been considered as a forceful means to accelerate the sluggish NRR reaction kinetics. Herein, we reported the design of Fe-doped NiMoO 4 catalysts for NRR. Fe doping can increase the amount of OVs in the catalyst and contribute to lattice strain enhancement, thereby leading to the improvement of the electron transport rate and catalytic active for NRR. In 0.1 M Na 2 SO 4 solution, the 5% Fe-NiMoO 4 catalyst achieves a NH 3 yield rate of 15.36 μg h -1 mg cat. -1 and a Faradaic efficiency of 26.85% under -0.5 V versus RHE. Furthermore, the 5% Fe-NiMoO 4 catalyst exhibits excellent stability (up to 13 h) during the reaction.