Controlled Electrodeposited of Cobalt Oxide Nanoparticles on Graphenized Pencil Lead Electrode as Efficient Electrocatalyst for Oxygen Evolution Reaction in Alkaline Medium

In this study cobalt oxide nanoparticles were electrodeposited on the surface of graphenized pencil lead electrode (GPLE) as a low cost and efficient electrocatalyst for the OER in alkaline media. The prepared cobalt oxide modified GPLE (CoOx/GPLE) was carefully characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, electrochemical impedance spectroscopy and cyclic voltammetry techniques. The developed electrocatalyst represents remarkably low OER overpotential of 1.41V (vs. RHE) at the current density of 10 mA cm-2 and Tafel slope of 149 mV dec-1 in 0.1 M KOH solution. The CoOx/GPLE was highly stable and capable for maintaining catalytic activity for at least 5 h. Due to distinctive electrical conductivity, high mass transfer, and adequate active sites of GPLE, the electrocatalytic activity of the cobalt oxide nanoparticles were incredibly improved in CoOx/GPLE.