Co–Ni Synergy Engineered in a Perovskite for Highly Selective Nitrate Electroreduction to Ammonia

Perovskite oxides have emerged as promising electrocatalysts for the nitrate reduction reaction (NO₃RR) to ammonia, yet their practical application is often limited by unsatisfactory ammonia selectivity, low yield, and poor suppression of competing reactions. Herein, we develop a multimetallic perovskite electrocatalyst, La_0.5Sr_0.5Co_0.5Ni_0.5O₃ (LSCNO), via a sol-gel method. Density functional theory (DFT) results show that Ni doping regulates the electronic structure of Co and shifts its d-band center upward. This optimization lowers the energy barrier of the *NO → *NOH rate-determining step and accelerates nitrate-reduction kinetics, further enhancing the intrinsic catalytic activity. As a result, LSCNO delivers a remarkable NO₃RR performance, achieving a Faradaic efficiency of 94.96% and an NH₃ yield rate of 9475.9 μg h^-1 cm^-2 at -0.5 V vs RHE, while maintaining excellent stability during 12 consecutive cycles and prolonged operation at a current density οf 150 mA cm^-2. When implemented in a flow-cell system, compared to H-type electrolytic cells, the catalyst enables a steady increase in the ammonia yield at lower potential. Furthermore, a Zn-NO₃ ^- battery assembled with an LSCNO cathode delivers a peak power density of 10.19 mW cm^-2 and outstanding long-term cycling durability over 10,000 min. These results highlight LSCNO as a highly efficient and stable catalyst for nitrate-to-amine conversion, demonstrating significant potential for practical nitrogen-resource recovery and sustainable energy storage.