Efficient electrochemical nitrate-to-ammonia conversion using nitrate-intercalated CuCo layered double hydroxide

Electrocatalytic nitrate reduction reaction (eNitRR) offers a promising approach to converting waterborne nitrate pollutants into recoverable ammonia. However, current catalysts are limited by low reduction efficiency, poor selectivity toward ammonia, short operational lifespan, and the high cost of noble metals. In this work, we develop a low-cost, two-dimensional NO₃^--intercalated copper-cobalt layered double hydroxide (CuCo LDH) supported on nickel foam. The NO₃^--intercalated CuCo LDH achieves a 99.1 % nitrate removal rate and 94.1 % ammonia selectivity within 100 min, with an ammonia yield of 1.06 mmol h^-1 cm^-2. Even after 20 consecutive cycles, the system maintains over 72 % Faradaic efficiency for ammonia (FE_NH3). The CuCo LDH@NF electrode enhances NO₃^- adsorption, modulates the adsorption/desorption of ∗H, and accelerates mass transport at the electrode-electrolyte interface. Cu-Co bimetallic active sites on the nanomaterial surface facilitate the tandem catalysis of NO₃^- to NH₃, enabling efficient and selective electrochemical nitrate-to-ammonia conversion. These findings highlight a viable and scalable strategy for low-cost cathode development in electrochemical nitrate-to-ammonia conversion.