Dual‐Site W‐O‐CoP Catalysts for Active and Selective Nitrate Conversion to Ammonia in a Broad Concentration Window

Abstract

Abstract Environmentally friendly electrochemical reduction of contaminated nitrate to ammonia (NO 3 − RR) is a promising solution for large quantity ammonia (NH 3 ) production, which, however, is a complex multi‐reaction process involving coordination between different reaction intermediates of nitrate reduction and water decomposition‐provided active hydrogen (H ads ) species. Here, a dual‐site catalyst of [W‐O] group‐doped CoP nanosheets (0.6W‐O‐CoP@NF) has been designed to synergistically catalyze the NO 3 − RR and water decomposition, especially the reactions between the intermediates of NO 3 − RR and water decomposition‐provided H ads species. This catalytic NO 3 − RR exhibits an extremely high NH 3 yield of 80.92 mg h −1 cm −2 and a Faradaic efficiency (FE) of 95.2% in 1 m KOH containing 0.1 m NO 3 − . Significantly, 0.6W‐O‐CoP@NF presents greatly enhanced NH 3 yield and FE in a wide NO 3 − concentration ranges of 0.001–0.1 m compared to the reported. The excellent NO 3 − RR performance is attributed to a synergistic catalytic effect between [W‐O] and CoP active sites, in which the doped [W‐O] group promotes the water decomposition to supply abundant H ads , and meanwhile modulates the electronic structure of Co for strengthened adsorption of H ads and the hydrogen (H 2 ) release prevention, resultantly facilitating the NO 3 − RR. Finally, a Zn‐NO 3 − battery has been assembled to simultaneously achieve three functions: electricity output, ammonia production, and nitrate treatment in wastewater.