Boosting electrochemical nitrate-to-ammonia conversion by self-supported MnCo2O4 nanowire array

Direct electrocatalytic reduction of nitrate (NO 3 – ) is an efficient route to simultaneously synthesize ammonia (NH 3 ) and remove NO 3 – pollutants under ambient conditions, however, it is hindered by the lack of efficient and stable catalysts. Herein, a self-supported spinel-type MnCo 2 O 4 nanowire array is demonstrated for exclusively catalyzing the conversion of NO 3 – to NH 3 , achieving a high Faradic efficiency of 97.1% and a large NH 3 yield of 0.67 mmol h −1 cm −2 . Furthermore, density functional analysis reveals that MnCo 2 O 4 (220) surface has high activity for NO 3 – reduction with a low energy barrier of 0.46 eV for *NO to *NOH.