Ru Single Atoms Anchored in Metal Borides Enable Hydrogen Spillover for Superior Electrochemical Ammonia Production

Abstract The electrochemical reduction of nitrate represents a promising and sustainable route for valuable ammonia generation. However, a vital challenge in the nitrate reduction reaction is an insufficient supply of active hydrogen ( * H) and slow kinetics at a low working potential, which result in low production efficiency and high energy consumption. Here, we report the single‐atom Ru‐decorated nanoporous metal borides as a high‐performance electrochemical nitrate reduction electrocatalyst utilizing an atomic‐scale hydrogen spillover effect. Notably, the Ru SA /np‐Ni 3 B exhibits a high NH 3 Faradaic efficiency of 96.2%, an NH 3 yield of 30.4 mg h −1 mg −1 , and an energy efficiency of 39.1% at −0.1 V versus RHE. In situ electrochemical characterizations and theoretical calculations reveal that single‐atom Ru anchored in nanoporous Ni 3 B not only can efficiently dissociate water into * H and simultaneously promote the * H spillover for increasing * H coverage on the surface but also can optimize surface states of Ni 3 B active centers, which synergistically reduces the hydrogenation energy barrier for converting nitrate into valuable ammonia products. A two‐electrode electrolyzer integrating nitrate reduction reaction with furfuryl alcohol oxidation reaction achieves current density of 1 A cm −2 at −1.72 V with 100 h stability, improving the energy efficiency and economy of the system.