Electrocatalytic conversion of nitrates to produce high-valueadded NH 3 exhibited promise as a replacement for the Haber−Bosch process due to the involvement of an eight-electron and nine-proton transfer in the electrocatalytic nitrate reduction reaction (NO 3 RR), which exhibits low Faradaic efficiency and selectivity toward NH 3 . Herein, a cobalt molybdate catalyst was in situ grown on nickel foam with abundant oxygen vacancies and a rich unsaturated coordination Mo 4+ environment by a rapid Joule heating method. The synergistic optimization of these features modulated the overall catalyst electronic structure, achieving both high activity and high selectivity in NO 3 RR. Specifically, in an electrolyte of 0.1 M K 2 SO 4 and 1000 mg NO3 − /L, a Faradaic efficiency of 94.6% and a NH 3 yield rate of 1.32 mg h −1 cm −2 were achieved at −0.35 V vs RHE. Meanwhile, the selectivity of NH 3 reached 97% after the 12 h test. In six consecutive cycles and during a 12 h extended stability assessment, the CMO/NF-800 catalyst consistently exhibited exceptional chemical stability. DFT results demonstrated that nitrate adsorption and ammonia desorption were more readily achieved on the surface of the CMO/NF-800 and that there was a lower energy barrier that needed to be overcome for RDS. This work provided a reservable approach to the preparation of catalysts with abundant unsaturated coordination environments on the highly selective electroreduction of nitrate into ammonia.