Palladium‐Doping‐Enabled Interface Synergy for Superb Ampere Level Ammonia Electrosynthesis From Nitrate

The practical electrocatalytic nitrate‐to‐ammonia conversion suffers from insufficient performance at industrial current densities. Here, we report an electrochemically reconstructed Pd‐doped Co catalyst that achieves > 98.0% ammonia Faradaic efficiency at an ultrahigh partial current density of ‒1.43 A cm −2 and operates stably for over 170 h. Integrated in situ spectroscopy and theoretical simulations reveal a dual‐enhancement mechanism, in which Pd doping lowers the energy barrier of the rate‐determining *NO hydrogenation step and reconstructs the interfacial microenvironment. This restructuring promotes cation enrichment and establishes a dynamic hydrogen‐down‐oriented water network, facilitating proton transfer and intermediate stabilization under high‐flux conditions. Unlike its role in Cu‐based systems, Pd in the Co matrix distinctly optimizes the kinetics of surface intermediates, enhances the local interfacial electric field, and increases the flexibility of the hydrogen‐bond network. This work demonstrates the critical synergy between atomic‐site engineering and microenvironment control for achieving high‐rate electrocatalysis beyond conventional electronic modulation.