A Bio-inspired Nitrogen Doped NiO as Bifunctional Catalysts for Urea-water Electrolysis

Urea assisted water electrolysis has been proposed to produce hydrogen owing to lower theoretical oxidation potential of urea oxidation reaction (UOR) than the sluggish oxygen evolution reaction (OER) at the anode. However, the UOR with six-electron transfer process is also slow and complex, which needs catalysts to reduce its overvoltage. In this paper, inspired by the structure of urease in organisms a N-doped NiO heterogeneous biomimetic catalytic electrode was designed for UOR. The N-NiO biomimetic catalytic electrode was prepared by a two-step method. By equipping N-NiO as both anode and cathode, the electrode potential was only 1.55 V at current density of 10 mA cm-2 in urea assisted water electrolysis which is much lower that in water electrolysis., indicating its potential for the application.