Atomic scale distortion enables optimal Cu–Co coupling for selective electrochemical nitrate to ammonia conversion in neutral electrolytes

Electrochemical nitrate reduction (NO₃RR) to ammonia (NH₃) offers a sustainable pathway for wastewater treatment and nitrogen upcycling. However, its practical implementation remains challenging due to sluggish intermediate kinetics and competitive hydrogen evolution, fundamentally arising from an insufficient understanding of how local coordination structures dictate reaction kinetics and selectivity. In particular, NO₃RR in neutral electrolytes is especially challenging due to limited proton availability and unstable interfacial microenvironments that hinder proton-coupled electron transfer and nitrate adsorption. Here, we develop a strategy to deliberately regulate atomic coordination in trimetallic Co–CuAl layered double hydroxides (LDHs). Valence-state modulation induced by Co incorporation triggers Jahn–Teller-like distortion within the LDH lattice, leading to structural reconfiguration and systematic modulation of metal–oxygen and metal–metal interatomic distances. This distortion-driven structural evolution reshapes the local coordination environment and precisely adjusts the spatial coupling between Cu and Co active sites, establishing an optimal coordination environment that facilitates a tandem effect between active sites. By correlating interatomic distance variation with catalytic performance, we identify an optimal atomic configuration that accelerates the kinetically limiting step and promotes the NO₃RR pathway over the competing hydrogen evolution reaction. This strategy delivers significantly enhanced NH₃ selectivity and yield under neutral conditions, offering fundamental insights into the design of high-performance LDH-based electrocatalysts. © 2026 Published by Elsevier Ltd.