Dynamic catalytic interface driven three-step synergistic mechanism for boosting ammonia and hydroxylamine synthesis

Despite the short-term industrial landscape remaining unchanged, green synthesis technologies for ammonia (NH₃) and hydroxylamine (NH₂OH) are critical for carbon neutrality. Alternatively, electrocatalytic nitrate reduction (NIRR) can be integrated with membrane separation technology via a modular design, simultaneously achieving pollution control and resource recovery. However, the microscopic mechanism of NIRR remains ambiguous given the complex dynamic catalytic interface, hindering advanced catalyst development. Here, we propose a three-step synergistic mechanism at dynamic catalytic interface, which integrates interfacial microenvironment regulation, OH species cycle, and reverse hydrogen spillover for efficient NH₃ and NH₂OH synthesis across different scenarios. Notably, dual-site heterostructure catalyst exhibits almost 100% NH₃-Faradaic Efficiency (FE_NH3) across a wide nitrate concentration range, reaching a maximum NH₃ yield of 10.27 mmol h^-1 cm^-2. The simultaneous NH₃ synthesis-recovery system maintains almost 100% FE_NH3 and NH₃ recovery efficiency over 120 h, accompanied by long-term durability and negligible performance degradation. Additionally, cyclopentanone-mediated NIRR process delivers a satisfactory NH₂OH-Faradaic Efficiency (83.48%), and the assembled zinc-nitrate battery achieves a high peak power density (57.6 mW cm^-2).