Delocalized Electronic State Mediated NiCoOOH Enables Selective Urea‐to‐Nitrite Oxidation for Direct Urea Fuel Cells

ABSTRACT Selective oxidation of urea to nitrite (NO 2 − ) rather than N 2 is desireable for Direct urea fuel cells (DUFCs), doubling the electron yield per molecule while suppressing gas accumulation. Herein, we report a NiCoOOH model catalyst in which cobalt incorporation stabilizes electron‐delocalized states around Ni sites, thereby steering the oxidation pathway toward selective urea‐to‐nitrite conversion. In situ Raman and infrared spectroscopies reveal that NiCoOOH triggers the formation of hydroxyl oxide species at potentials as low as 1.32 V vs. RHE while simultaneously promoting urea adsorption. The markedly attenuated *CO 2 vibrational signal indicates suppression of the N 2 ‐evolution and supports a reaction pathway in which OH − preferentially attacks the C─N bond. Consequently, NiCoOOH achieves a Faradaic efficiency of 84.7% for liquid nitrogen oxides (NO x − ), representing a 21.5% improvement over Ni(OH) 2 , and requires only 1.48 V to deliver 500 mA cm −2 with stable operation for 100 h. Leveraging these advantages, the catalyst enables a 380 mV voltage saving in urea‐assisted water splitting. Furthermore, a flow‐type DUFC affords a peak power density of 18.98 mW cm −2 , and a pouch‐type DUFC successfully powers an LED and an electronic timer, confirming the practical viability of this urea‐to‐nitrite strategy in energy devices.