Symmetry-breaking engineering of Mn dual-atom catalyst for efficient and stable urea electrosynthesis

The electrocatalytic synthesis of urea offers a sustainable alternative to the energy-intensive industrial processes, yet it is challenged by the inefficient C-N coupling step. Herein, we employ symmetry breaking engineering to construct Mn dual-atom sites with an asymmetric electronic structure on oxygen-doped boron nitride (Mn₂-N₃O₃/BN) for efficient urea electrosynthesis from CO₂ and nitrate (NO₃^-). Compared to its symmetric single-atom counterpart (Mn-N₄/BN), the Mn₂-N₃O₃/BN catalyst exhibits significantly enhanced performance, achieving a urea yield rate of 43.78 mmol h⁻¹ g⁻¹ at −0.6 V vs the reversible hydrogen electrode (RHE), and a Faradaic efficiency (FE) of 40.6% at −0.5 V vs. RHE, along with exceptional operational stability for over 120 h. Through a combination of in situ spectroscopic analysis and density functional theory (DFT) calculations, we demonstrate that the asymmetric dual-atom sites uniquely modulate the local electronic environment, which simultaneously enhances the adsorption of key C- and N-intermediates and lowers the energy barrier for the decisive C-N coupling step. This work highlights the critical role of asymmetric charge regulation in breaking the scaling relationship for multi-electron reactions and provides a rational design blueprint for advanced dual-atom catalysts in sustainable nitrogen and carbon conversion.