La‐Mediated Interfacial Electric Field Effect Steers Mesoscopic Mass Transport for Highly Selective Urea Oxidation

ABSTRACT Coupling active site urea adsorption with mass transport is critical to precisely tuning the selectivity of the electrocatalytic urea oxidation (UOR). However, current research on selectivity remains focused on atomic‐level active sites, while often neglecting the vital influence of mesoscopic mass transport from electrode structures. Herein, we utilize the lanthanide (La) mediated interfacial electric field strategy to regulate ion deposition behavior, enabling the controllable synthesis of catalyst mesostructures. In situ spectroscopic characterization combined with multiscale simulations comprehensively elucidates the dynamic mechanism of the electrodeposition process. The low‐La‐doped Ni‐based catalyst (La‐Ni NSs) features a flat surface with oxygen‐affinity sites, enabling tailored urea adsorption configurations and optimized mesoscopic mass transport during UOR, and thus realizing efficient dynamic cycling of urea and OH − at the catalyst's surface active sites for boosted UOR selectivity. Consequently, utilizing the high UOR selectivity of this material to assemble a membraneless electrolytic cell, which sustained a stable current density of 1.0 A cm −2 at just 1.7 V for over 1500 h. This work develops a La‐mediated mesostructuring strategy to achieve highly efficient electrocatalytic selectivity by regulating the dynamic competition of reactants in electrocatalytic systems via mesoscopic mass transport.