Controlled Hydrogen Delivery by Single-Atom Ru Accelerates Electrocatalytic Ammonia Synthesis

Electrocatalytic nitric oxide reduction to ammonia (NORR) offers a dual opportunity for NO remediation and decentralized NH₃ production, yet its efficiency is often limited by competing pathways and unclear structure-function relationships. Here we introduce a reactant-shunting strategy that installs a guiding electrocatalytic step via isolated Ru atoms to supply surface-bound ^*H species and enforce a Langmuir-Hinshelwood (LH) hydrogenation pathway. Using Ru₁/Co₃O₄ as a model catalyst, we show that single Ru sites promote water adsorption and dissociation, forming stable Ru-H intermediates that thermodynamically and kinetically accelerate the coupling-hydrogenation steps in NORR. The optimized catalyst delivers an NH₃ yield of 533.49 µmol cm^-2 h^-1 with a 97.19% faradaic efficiency, surpassing state-of-the-art systems. The reactant-shunting principle further generalizes across multiple oxide hosts, enhancing NH₃ productivity by up to threefold. These findings establish pathway steering through controlled hydrogen delivery as a powerful strategy for high-efficiency electrocatalytic ammonia synthesis.