THIN-FILMS OF CO3O4 AND NICO2O4 OBTAINED BY THE METHOD OF CHEMICAL SPRAY PYROLYSIS FOR ELECTROCATALYSIS .3. THE ELECTROCATALYSIS OF OXYGEN EVOLUTION

The electrocatalytic properties of thin Co3O4 and NiCo2O4 films prepared on CdO-nonconductive glass by the method of chemical spray pyrolysis were investigated for oxygen evolution in varying KOH concentrations. The Tafel slopes were close to (2.3 RT/F) V per decade for both oxides. The reaction order with respect to [OH-] was found to be approximately 1.3. It was observed that Co3O4 is more active than NiCo2O4 towards oxygen evolution. A mechanism for oxygen evolution involving the electrochemical adsorption of OH- as a fast step and the electrochemical desorption of OH forming an intermediate H2O2 as the rate-determining step has been suggested. © 1990 Chapman and Hall Ltd.