Circumventing Scaling Relations via Gradient Orbital Coupling Promotes Ammonia Electrosynthesis on Cobalt Catalyst

Highly efficient electrocatalytic nitrate reduction to ammonia (NH3) relies on the balanced activation of various substrates including nitrate and water, but is currently hindered by the inherent scaling relations governing the adsorption of key reaction intermediates, such as *NO and *H. Herein, we develop a strategy to circumvent these limitations by introducing f-d-p gradient orbital coupling in cobalt oxide (Co3O4) through Ce doping. Density functional theory calculations indicate that the lattice strain triggered by the dopant redistributes electron density at the Co and O sites, thereby modulating the adsorption strengths of *NO and *H, which favors the production of NH3 while suppressing hydrogen evolution reaction. It exhibits a Faradaic efficiency of 97.8% and a high yield rate of 3423.0 µg h-1 cm-2 under alkaline conditions. Furthermore, Ce/Co3O4 catalyst shows robust performance over a wide range of nitrate concentrations (from 5 mM to 200 mM) and excellent cycling stability. Our findings also suggest that the gradient orbital coupling approach can be extended to other lanthanide dopants (e.g., Pr and Nd), offering a broadly applicable platform to break scaling relations and improve NO3--to-NH3 activity on cobalt catalysts.