Dual-Atomic Ruthenium Interdistance Mediated by Metal–Metal Multiple Bonds for Electrocatalytic Nitrate Reduction Optimization

Electrocatalytic nitrate (NO 3 – ) reduction offers an appealing approach for nitrate pollutant remediation and sustainable ammonia synthesis. As a typical weak field ligand, NO 3 – binds to the metal center weaker than most common anions, which is proposed to be a key bottleneck for efficient and selective electrocatalytic NO 3 – reduction. With the chelate effect and five-membered ring structure, bidentate bridging is considered to be an ideal mode to facilitate NO 3 - binding, which requires a dual-atomic site with appropriate metal–metal distance. By utilizing diruthenium complexes containing different Ru–Ru bonds as precursors, the Ru–Ru interdistance in diruthenium-based dual-atom catalysts (Ru 2 -DAC) is effectively tuned in this work. As a result, Ru 2 -DAC with an optimal Ru–Ru interdistance ( Ru═Ru/DAC ) exhibits remarkable electrocatalytic activity toward NO 3 – conversion to NH 3 under neutral pH (yield: 3.48 mg NH3 h –1 mg cat –1, FE: 95% at −0.3 V vs RHE), far superior to the analogous catalyst with inappropriate Ru–Ru interdistance ( Ru–Ru/DAC ). The substantially enhanced electrocatalytic NO 3 – reduction induced by Ru–Ru interdistance modulation is theoretically attributed to the simultaneous enhancement of NO 3 – adsorption and *NO 2 deoxygenation.