Anchoring Polydopamine on ZnCo₂O₄ Nanowire To Facilitate Urea Water Electrolysis

Abstract

Dealing with overcoming the sluggishness of the oxygen evolution reaction (OER), the urea oxidation reaction (UOR) existed. ZnCo2O4, an excellent OER electrocatalyst, its application towards UOR is studied with surface‐grown polydopamine (PDA). ZnCo2O4@PDA is produced over the surface of nickel foam by hydrothermal method followed by self‐polymerization of dopamine hydrochloride. Dopamine hydrochloride was varied in solution mixture to study the optimal growth of PDA necessary to enhance electrochemical activity. Hence, prepared ZnCo2O4@PDA is characterized by X‐ray diffraction, electronic structural, and morphology/microstructure studies for confirmation. With successful confirmation, the developed electrode material is applied towards UOR and ZnCo2O4@ PDA‐1.5, delivering an excellent low overpotential of 80 mV @ 20 mA/cm2 in the electrolyte mixture of 1 M potassium hydroxide + 0.33 M urea. Also, to support excellent UOR activity, other electrochemical properties such as tafel slope, electrochemical surface active sites, and electrochemical impedance spectroscopy are studied. Further, a schematic illustration explaining the UOR mechanism is shown to clearly understand the obtained electrochemical activity. Finally, urea water electrolysis is carried out in a two‐electrode symmetrical cell and compared with water electrolysis. This clearly shows the potential of the developed material for efficient electrochemical hydrogen production.