Architected Crystalline‐Amorphous Electrocatalyst Enables Energy‐Efficient Hydrogen Release from Ammonia

ABSTRACT Ammonia is a promising hydrogen carrier due to its high hydrogen density, established infrastructure, and carbon‐free decomposition, yet its practical deployment via thermal catalysis is limited by high operating temperatures, catalyst cost, durability, and purification requirements. Electrochemical coupling of the ammonia oxidation reaction (AOR) with the hydrogen evolution reaction (HER) offers a low‐temperature and energy‐efficient alternative to thermocatalytic ammonia cracking, enabling indirect hydrogen release under mild conditions and effectively circumventing the limitations of thermal catalytic processes. In this work, we report a hybrid crystalline‐amorphous catalyst that merges structural order with purposeful disorder, created by seamlessly electrodepositing amorphous Ni‐P onto in situ grown NiCuO nanosheets anchored on nickel foam (NiCuO@a‐Ni‐P/NF). This architected interface delivers high activity and long‐term stability for alkaline AOR. We further design a hybrid acid/alkali electrolyzer in which anodic alkaline AOR is elegantly coupled with cathodic acidic HER, enabled by NiCuO@a‐Ni‐P/NF and Pt/C, respectively. The resulting system operates with stable performance, enduring 360 h of continuous electrolysis without discernible decay, and sustaining hydrogen generation with near‐quantitative Faradaic efficiency. These advances expand the conceptual framework and provide a viable route toward efficient, durable, and energy‐saving hydrogen production from ammonia.