ENHANCEMENT OF SURFACE-AREAS OF CO3O4 AND NICO2O4 ELECTROCATALYSTS PREPARED BY SPRAY-PYROLYSIS

Nickel and cobalt cobaltites have been prepared as thin films by spray pyrolysis of solutions containing cobalt and nickel nitrates. An alka li nitrate has been added to the sprayed solution which remained undec omposed during the formation of the oxide film. Then, this alkali nitr ate dissolved leading to an enhancement of the roughness of the films which can be controlled, We report herein the preparation and characte rization of such films by X-ray diffraction, FTIR reflectance spectros copy, scanning electron microscopy and electrochemical methods, The ro ughness factors have been determined by cyclic voltammetry. An increas e of the roughness, up to ten times, has been observed, The stationary I-E curves are representative of the good correlation between the mag nitude of the currents obtained and the roughness factors. Owing to ex perimental evidence and considering the low preparation temperature, w e have rejected the possibility of incorporation of the alkali ions in the crystalline lattice.