Synergistic Engineering of Doping and Vacancy in Ni(OH)(2) to Boost Urea Electrooxidation

Nickel hydroxide (Ni(OH)(2)) has been identified as one of the best promising electrocatalyst candidates for urea oxidation reaction (UOR) due to its flexible structures, wide compositions, and abundant 3d electrons under alkaline conditions. However, its layered structure with limited exposed edge sites severely hinders further improvement of the UOR activity. Herein, oxygen-vacancy rich and vanadium doped Ni(OH)(2) (O-vac-V-Ni(OH)(2)) catalysts are prepared and synergistically boost the urea electrooxidation. Vanadium doping contributes more exposed active sites, and simultaneously generates oxygen vacancies, switching the rate-determining step of UOR from *COOH deprotonation to the N-H bond cleavage process and lowering the thermodynamic barrier by around 1.13 eV. The novel O-vac-V-Ni(OH)(2) demonstrates good electrocatalytic performances with a working potential of 1.47 V at a high current density of 100 mA cm(-2). Synergistic engineering of doping and oxygen vacancy is a promising strategy for designing efficient UOR electrocatalysts.