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

Electrocatalytic nitrate (NO₃⁻) reduction offers an appealing approach for nitrate pollutant remediation and sustainable ammonia synthesis. As a typical weak field ligand, NO₃⁻ binds to the metal center weaker than most common anions, which is proposed to be a key bottleneck for efficient and selective electrocatalytic NO₃⁻ reduction. With the chelate effect and five-membered ring structure, bidentate bridging is considered to be an ideal mode to facilitate NO3⁻ 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 (Ru₂-DAC) is effectively tuned in this work. As a result, Ru₂-DAC with an optimal Ru-Ru interdistance (Ru═Ru/DAC) exhibits remarkable electrocatalytic activity toward NO₃⁻ conversion to NH₃ under neutral pH (yield: 3.48 mgNH3 h⁻¹ mgcat⁻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 NO₃⁻ reduction induced by Ru-Ru interdistance modulation is theoretically attributed to the simultaneous enhancement of NO₃⁻ adsorption and *NO₂ deoxygenation.