Metallic-State Ti ₂ O with Polarized Motifs Boosting Efficient Ammonia Electrosynthesis

Transition metal oxides with tailored polar architectures are vital for tuning electrocatalytic performance by regulating charge transfer and intermediate adsorption. For instance, TiO2 exhibits corrosion resistance and inherently suppressed hydrogen evolution reaction (HER) activity, which is essential for nitrate reduction reaction (NO3RR). However, its poor conductivity restricts the reaction kinetics. Herein, we address this issue by engineering metallic dititanium oxide (Ti2O) through Ti–Ti bond formation within [OTi6] octahedra, giving rise to polarized [Ti–Ti–O–Ti] motifs. This polarized oxide support enhances conductivity and triggers local electron redistribution. Integrating Cu single atoms onto the polarized Ti2O support achieves a current density of 233 mA cm–2, a Faraday efficiency of 91.26%, and a NH3 yield rate of 19.16 mg h–1 cm–2. Combined experimental and theoretical analyses demonstrate that [Ti–Ti–O–Ti] motifs accelerate the water-to-*H conversion, whereas Cuδ+ sites stabilize the adsorption of key intermediates. Their synergistic interplay enables efficient ammonia electrosynthesis on Ti2O–Cu electrode. This work pioneers polarity-engineered oxide support as a versatile platform for electrocatalyst design toward ammonia production.