CoSe2 nanowire array enabled highly efficient electrocatalytic reduction of nitrate for ammonia synthesis

The electrocatalytic reduction of nitrate (NO3–) not only facilitates the environmentally sustainable production of ammonia (NH3) but also purifies water by removing NO3–, thereby transforming waste into valuable resources. The process of converting NO3– to NH3 is complex, involving eight electron transfers and multiple intermediates, making the choice of electrocatalyst critical. In this study, we report a cobalt selenide (CoSe2) nanowire array on carbon cloth (CoSe2/CC) as an effective electrocatalyst for the NO3– to NH3 conversion. In an alkaline medium with 0.1 mol/L NO3–, CoSe2/CC demonstrates exceptional NH3 Faradaic efficiency of 97.6% and a high NH3 yield of 517.7 μmol h–1 cm–2 at –0.6 V versus the reversible hydrogen electrode. Furthermore, insights into the reaction mechanism of CoSe2 in the electrocatalytic NO3– reduction are elucidated through density functional theory calculations.