Emerging Atomically Engineered RuNi‐Zn‐ZIF‐8 Catalyst for Remarkably High Electrocatalytic Nitrate Reduction to Ammonia and Electrocatalytic Oxygen Evolution Reaction

ABSTRACT Here, we report an atomic substitution strategy between RuNi‐Alloy and ZIF‐8 to synthesize Ni single‐atom catalyst (SAC) supported on a carbon‐nitrogen framework (CNF), derived via high temperature calcination (900°C) of RuNi‐ZIF‐8. The resulting atomically engineered (RuZn)/Ni‐CN exhibits multifunctional activity for both Nitrate reduction reaction (NO 3 RR) and Oxygen evolution reaction (OER). In NO 3 RR, (RuZn)/Ni‐CN delivers a high ammonia yield of 10199 µg h −1 mg −1 cat with 84% Faradaic efficiency (FE) at −0.9 V vs. RHE. This performance is obtained using a Pt anode in a 0.1 M NaNO 3 solution containing 0.1 m Na 2 SO 4 , following the optimization of pH. (RuZn)/Ni‐CN achieves superior OER performance, with an overpotential of 303 mV at 50 mA cm −2 and exhibits low charge transfer resistance (0.43 Ω) and a small Tafel slope (62 mV/dec), indicating fast reaction kinetics. The TOF reaches 0.3278 × 10 −3 s −1 and retains long‐term operational stability with negligible degradation for 30 h. (RuZn)/Ni‐CN acted as a bifunctional catalyst in cathode and anode and delivered highest ammonia yield and FE of 10123 µg h −1 mg −1 cat and 83%, respectively. EXAFS and structural analyses confirm strong metal‐support interactions, with Ni as coordinatively unsaturated single atoms and minor clusters that synergistically enhance activity.