Unlocking Synergistic Electrocatalysis: A ZIF-67-Derived Ni-Doped Co–N–C Bimetallic Catalyst for Efficient Nitric Oxide Reduction to Ammonia

To address the high energy consumption and low efficiency associated with traditional ammonia synthesis, we developed a nickel-doped cobalt-based bimetallic catalyst (CoNi-NC) derived from ZIF-67 for the efficient electrocatalytic reduction of nitric oxide (NO) to ammonia (NORR). The CoNi-NC-x catalyst, which features cobalt nanoparticles measuring 5–10 nm on a carbon support, was synthesized by introducing Ni2+ ions into ZIF-67 followed by vacuum pyrolysis. The incorporation of nickel optimized the electronic configuration of cobalt, maintained a high specific surface area, and improved the distribution of active sites. Electrochemical tests indicated that CoNi-NC-2 achieved an ammonia production rate of 19.7 μmol cm–2 h–1 and a Faraday efficiency of 15.8% at −1.0 V vs. RHE, outperforming Co-NC. Additionally, the catalyst exhibited excellent stability. The Zn-NO battery utilizing this catalyst facilitated the synergistic removal of NO, ammonia synthesis, and power generation, achieving a peak power density of 1.34 mW cm–2 and an open-circuit voltage of 1.91 V. Density functional theory calculations revealed that nickel doping reduced the d-band center of cobalt, weakened NO adsorption, and activated the N–O bond, thereby enhancing NORR activity.