High-entropy-driven kinetic steering of urea electrooxidation enables coupled nitrite reduction for rapid...

The electrochemical urea oxidation reaction (UOR) is thermodynamically favorable toward N₂ formation. However, achieving selective N₂ production is kinetically challenged due to the underlying multistep mechanism involving bond cleavage and N-N bond formation. Herein, we report a high-entropy-driven kinetic steering strategy that accelerates the intrinsically favored "cyanate" pathway and couples it with selective NO₂^- reduction to achieve rapid urea-to-nitrogen conversion. A high-entropy oxide, CeMoCuFeCoO_x (CMCFCO), steers UOR toward fast C-N cleavage and NO₂^- formation via entropy-induced site isolation. Coupled with a S-CuFe cathode in a flowing single-chamber membrane-free electrochemical cell (EC), the generated NO₂^- is selectively reduced to N₂, preventing NO₂^- accumulation. Without iR compensation, CMCFCO delivers 300 mA cm^-2 at 1.69 V_RHE, and exhibits a pseudo-first-order rate constant of 0.068 min^-1, 2.6-4.0 times higher than low-entropy oxides. S-CuFe reaches 1.48 A cm^-2 at -1.3 V_RHE. At 300 mA cm^-2 in 1.5 M KOH + 0.33 M urea, 92.7% urea removal is achieved within 40 min with 93.8% Faradaic efficiency toward N₂ products. In situ spectroscopy and DFT reveal that high-entropy-induced site isolation accelerates cyanate formation, while interfacial *N coupling on S-CuFe promotes selective N₂ generation. This reaction-coupling framework reconciles kinetic accessibility with thermodynamic selectivity in UOR.