Enhancing nitrate electroreduction for ammonia production over electron-deficient Co3O4 with La doping regulation

Electrocatalytic reduction of nitrate (NO 3 − ) can efficiently transform NO 3 − into ammonia (NH 3 ), enabling the simultaneous removal of NO 3 − pollutant from wastewater and the production of NH 3 . Here, we report the use of rare-earth lanthanum-doped Co 3 O 4 nanowires array on carbon cloth (La-Co 3 O 4 /CC) as an efficient electrocatalyst for the conversion of NO 3 − to NH 3 . The as-synthesized La-Co 3 O 4 /CC demonstrates a remarkable NH 3 Faradaic efficiency (96.36%) and NH 3 yield (537.44 µmol h −1 cm −2 ), markedly surpassing its Co 3 O 4 counterpart (87.78%, 279.4 µmol h −1 cm −2 ). Theoretical computations unveil that the incorporation of La doping promotes NO 3 − adsorption and optimizes the hydrogenation process, thus enhancing the electroreduction activity of Co 3 O 4 in NO 3 − conversion and NH 3 selectivity. Furthermore, a Zn–NO 3 − battery incorporating La-Co 3 O 4 /CC achieved a peak power density of 9.86 mW cm −2 . This work advances the application of Co 3 O 4 -based electrodes in electrocatalysis and highlights the effectiveness of rare earth element doping in NO 3 − reduction reactions.