An insight of photoelectrochemical driven urea oxidation from nickel manganese oxide nanostructures

Abstract

Nickel manganese spinel oxide finds tremendous application in electronic and electrochemical devices because of its high redox activity and better durability. Here, we have stabilized nickel rich, nickel manganese oxide Ni6MnO8 through chemical route and studied their application in electrochemical urea oxidation. The as-prepared Ni6MnO8 affords a two-fold high performance toward urea oxidation reaction as photoanode with a maximum peak current density of 44.58 mAcm−2 and exhibited low overpotential of 1.39 V at 10 mAcm−2. Smaller Tafel slope value (16 mV/decade) and 12 h chronoamperometry stability show faster rate kinetics and better durability as photoanode electrocatalyst for urea electrocatalysis. The robust photoelectrochemical urea oxidation is due to Ni2+/Ni3+ redox active species. The present work is sunlight-driven and sustainable approach for hydrogen production and remediation for urea-rich wastewater. It is the first time Ni6MnO8 used as promising photoanode for urea electrocatalysis.