Gradient energy alignment drives catalytic cascades for synergistic nitrate-to-ammonia electro-conversion

Although tandem-site multiphase catalysts have been explored for the electrochemical conversion of nitrate to ammonia (NH 3 ), achieving genuine phase synergy remains challenging due to energetic mismatches across the interface. Herein, a pre-infusing pyrolytic fusion strategy is developed to construct partially polarized Ag clusters on a Co 3 O 4 support (PP-Ag/Co 3 O 4 ). Strong interfacial electronic coupling stabilizes Ag δ + sites. These Ag δ + construct the relay sites with a gradient energy alignment feature, thereby facilitating a catalytic cascade enabling effective coupling between nitrate activation on Ag and subsequent hydrogenation on Co 3 O 4 . Experimental results demonstrate that PP-Ag/Co 3 O 4 achieves a notable NH 3 Faradaic efficiency of 96.2%, a yield rate of 12.3 mg h −1 cm −2 under neutral conditions. Furthermore, the constructed Zn-NO 3 − battery based on PP-Ag/Co 3 O 4 delivers an impressive power density of 5.42 mW cm −2 . This work highlights energy alignment engineering as an effective strategy for advancing efficient ammonia electrosynthesis.