Electrochemical oxygen evolution on fabricated Ni/Ni0.3Co2.7O4 in alkaline medium

The Ni0.3Co2.7O4 was prepared by the low temperature sol-gel route using span-60 as precursor for electrochemical formation of oxygen in alkaline medium. The prepared oxide was characterized by the FTIR, P-XRD and SEM techniques to ensure their formation, structure and morphology. The oxide electrode was fabricated on nickel support and tested for their electrochemical activity by the cyclic voltammetry and the Tafel polarization techniques. The cv curve of oxide electrode exhibited a couple of redox peaks, one cathodic peak (Epa = 168 mV) and another anodic peak (Epa = 550 mV). The electrocatalytic activity for OER was tested by the Tafel polarization technique. Investigation showed that Ni0.3Co2.7O4 was found to be highly electrode for OER with the Tafel slope value 128 mV dec-1 and current density (j) of 50 mA cm-2 at 379 mV oxygen over potential and the OER followed first order reaction kinetics with respect to the change in [OH−] concentration. The temperature-dependent parameters such as electrochemical activation energy (Ea) and standard entropy of reaction (Δ𝑆𝑒𝑙0≠) were also determined for the OER and their respective values are ~27 kJ mol-1and -303 J deg-1mol-1. A highly negative value of entropy of reaction suggests the involvement of adsorption phenomenon in OER.