Dynamic Asymmetry in O/N-Coordinated Zn Single-Atom Catalysts Promotes Sabatier-Favorable Urea and Urea Peroxide Electrosynthesis.

Abstract

Precise regulation of metal‒intermediate binding is essential for selective electrocatalysis, yet conventional symmetric single-atom coordination often limits directional adsorption control. Here we report an asymmetric O/N-co-coordinated Zn single-atom catalyst, Zn-O3N1-C, using symmetric Zn-O4-C as a structural counterpart. Structural characterization and x-ray absorption spectroscopy (XAS) confirm atomically dispersed Zn‒O3N1 sites, in which replacing one O ligand with less electronegative N not only breaks local symmetry, but also enriches Zn electron density and lowers the Zn oxidation state. Operando XAS further reveals that Zn-O3N1 undergoes cathodic-bias-induced electronic enrichment and anisotropic Zn─N/Zn─O bond response, amplifying local coordination polarization while preserving the isolated Zn─O/N framework. This dynamically polarized asymmetric coordination shifts Zn‒adsorbate interactions toward a Sabatier-favorable regime, enabling two adsorption-governed transformations. For CO2/nitrate co-reduction, Zn-O3N1-C promotes *NO/*NHO-mediated C‒N coupling. The same catalyst also demonstrates excellent electrocatalytic activity toward two-electron oxygen reduction reaction (2e- ORR). The electrosynthesized urea and H2O2 are further coupled to produce urea peroxide. Operando spectroscopy and density functional theory calculations reveal that asymmetric Zn-O3N1 coordination optimizes *NO/*NHO and *OOH binding, establishing dynamic coordination polarization as a design principle for selective single-atom electrocatalysis.