The Coupling of Rh‐Ru Dual Sites with Interfacial Oxygen Endows MoSe ₂ with Efficient Ammonia Electrosynthesis

Abstract The electrochemical nitritereduction reaction (NO 2 RR) to ammonia (NH 3 ) is an intricate multielectron coupled proton transfer process, involving the adsorption and deoxygenation of NO 2 − to form intermediates (*NO), followed by the protonation of *NO to generate NH 3 . Tandem catalysis is a promising approach for enhancing the NO 2 RR and suppressing side effects; however, it is still challenged by the lack of well‐designed catalysts to drive this catalytic process. Herein, a catalyst is introduced, featuring Rh−Ru atomic‐pair dual sites that couple with interfacial oxygen‐containing species confined within a MoSe 2 lattice (RhRu‐MoSe 2‐x O y ), enabling the unprecedented selective conversion of NO 2 − to NH 3 under a low potential. Systematic experimental and computational studies reveal that the construction of Rh‐Ru sites married with adjacent oxygen‐containing groups can achieve the synchronous dispatch of water activation and hydrogenation of NO 2 . Moreover, the nitrite reduction on RhRu‐MoSe 2‐x O y preferably proceeds via the NHO* pathway (NO*→NHO*), effectively circumventing the high energy barrier associated with the O‐side pathway (NO*→NOH*). Consequently, such a tandem system holds superior performance for robust NH 3 electrosynthesis at a relatively low potential, achieving a high NH 3 Faradaic efficiency of 93.0% at −0.2 V (vs RHE) and an exceptional NH 3 production rate of 9.2725 mmol h −1 mg cat −1 at –0.4 V. Furthermore, the resulting catalysts attain ultra‐low overpotentials in a membrane electrode assembly (MEA) electrolyzer, featuring cell voltages of 2.1 V at current densities of 400 mA cm −2 and stable operation under industrial conditions for 200 min.