Controllable synthesis of urea-assisted Co3O4 nanostructures as an effective catalyst for urea electrooxidation

Abstract

Nonprecious urea-assisted Co3O4 nanostructures with different urea concentrations were synthesized using a hydrothermal method. The structural variations of four different electrocatalysts of Co3O4 were investigated using X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy analyses. The change in morphology of all Co3O4 samples can be ascribed to urea-assisted controlled synthesis procedures. Linear sweep voltammetry, chronoamperometry, and electrochemical impedance spectroscopy studies were conducted using a three-electrode system to examine the electrocatalytic behavior of the samples for the urea oxidation reaction (UOR) in an alkaline medium. Co3O4 synthesized with a high urea concentration exhibited good electrocatalytic activity for the UOR. At an oxidation potential of 0.65 V, the self-assembled electrocatalysts delivered the highest current density of 98.6 mA g−1. This sample showed a higher electrochemical active surface area (ECSA-242.5 mF cm−2) and BET surface area (22.27 m2 g−1) than others. The enhanced electrocatalytic activity of this sample can be attributed to adding a higher urea concentration during the synthesis steps and its structural morphology, which enhanced the reaction kinetics.