A Mechanistic Study of Oxygen Evolution on NiCo2 O 4 : II . Electrochemical Kinetics

Oxygen evolution studies were carried out on pre‐anodized, Teflon‐bonded electrodes in electrolytes of eight different concentrations ranging from 0.1 to 5.0 mol dm −3 . Oxygen evolution was found to be governed by two Tafel regions, 0.04V per decade at lower overpotentials and 0.12V per decade at higher overpotentials, in electrolytes of concentration of 1.2 mol dm −3 and greater. In electrolytes of concentration less than 1.2 mol dm −3 , the Tafel slope of 0.04V per decade was not observed. The two Tafel regions have been discussed in relation to the activity of divalent and trivalent sites of toward oxygen evolution.