Computation‐Guided Design of Ru‐Based Intermetallic Catalysts Enabling Nearly 100% Selectivity for Electrocatalytic Ammonia Synthesis at Ultra‐Low Potential

Abstract Electrochemical nitrate reduction reaction (NO ₃ RR) holds significant promise for converting the NO ₃ ^⁻ pollutants into valuable ammonia (NH ₃ ), offering a sustainable alternative to the energy‐intensive Haber‐Bosch process by operating under mild conditions with renewable energy sources. However, unsuitable adsorption of *NO ₃ and inadequate supply of active hydrogen (*H) during the NO ₃ RR process lead to low Faradaic efficiency in NH ₃ production. Herein, density functional theory calculations are initially employed to evaluate the adsorption energies of *NO ₃ and *H adsorption energy for 13 Ru‐p‐block metal intermetallic compounds (IMCs). The results demonstrate that Ru‐Sb IMCs exhibit great potential as NO ₃ RR electrocatalysts, demonstrating exceptional NO ₃ ⁻ adsorption capacity and efficient suppression of competing hydrogen evolution reaction, outperforming the other Ru‐p‐block metal IMCs. As guided by the calculation results, Ru‐Sb IMCs supported on carbon black is synthesized, i.e., RuSb/C and RuSb ₂ /C. And RuSb/C exhibits impressive NO ₃ RR performance with an NH ₃ Faradaic efficiency of nearly 100% (99.7%) and exceptional stability at a low potential of ‐0.05 V, significantly exceeding those of most recently reported Ru‐based electrocatalysts for NO ₃ RR.