Electrochemical Studies on Protective Thin Co3 O 4 and NiCo2 O 4 Films Prepared on Titanium by Spray Pyrolysis for Oxygen Evolution

Electrochemical studies were done on thin and films on Ti by cyclic voltammetric and potentiostatic polarization techniques. The films were quite conductive and prevented the underlying surface from playing a harmful role during measurements. The results indicated the formation of a surface quasi‐reversible redox couple, Co IV /Co III , in solution. The reaction order with respect to OH − ion concentration was found to be nearly 2. The Tafel slopes decreased with increasing concentrations. was observed to evolve oxygen gas at a lower overpotential as compared to that of . Electrode kinetic parameters suggest similar mechanisms for the oxygen evolution for both the oxides.