Atomically Ordered RuGa Intermetallic Electrocatalyst Enables High‐Efficiency Nitrate‐to‐Ammonia Conversion

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Electrocatalytic nitrate reduction represents a green and sustainable route for ammonia synthesis. However, its practical application is still hindered by unsatisfactory selectivity, activity, energy efficiency, and stability, especially under low nitrate concentrations. Here a carbon‐supported atomically ordered ruthenium‐gallium intermetallic compound (RuGa IMC/C) is reported, characterized by orderly isolated Ru sites surrounded by catalytically inert Ga, which can serve as a highly efficient cathodic catalyst for nitrate‐to‐ammonia reduction, achieving a remarkable ammonia yield rate of 31.73 mg h −1 mg Ru −1 and an ammonia Faradaic efficiency of 97.03% as well as half‐cell energy efficiency of 40.94% at an ultralow potential of −0.05 V under a low nitrate concentration of 2000 ppm (0.032 M). Impressively, the RuGa IMC/C catalyst exhibits excellent Faradaic efficiencies (>90%) across a wide range of nitrate concentrations from 0.01 to 0.1 M at 0 V and a superior stability. Theoretical calculations reveal that incorporating Ga into Ru causes a shift of the d ‐band toward the Fermi level, optimizing the adsorption and activation of N‐containing intermediates while suppressing the competing hydrogen evolution reaction on the RuGa IMC/C. Furthermore, the assembled zinc–nitrate battery displays a maximum power density of 52.74 mW cm −2 and a long‐term durability of over 300 h.