Characterization of thin CuCo2O4 films prepared by chemical spray pyrolysis. Study of their electrochemical stability by ex situ spectroscopic analysis

Pure copper cobalt oxide with spinel structure can be prepared as thin films at 340 degrees C by chemical spray pyrolysis of the metal nitrate aqueous solution over conducting glass. Addition of ammonium nitrate to the sprayed solution increases the crystallization. We report herein the preparation and characterization of such films using X-ray diffraction, FTIR reflectance and transmission spectroscopy, W-vis spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, oxidation power, magnetic and conductimetric measurements. The copper ions are distributed over the A and B sites of the inverted spinel lattice and the cobalt ions are postulated to be in the low spin state. Oxide electrochemical stability has been determined by cyclic voltammetry. Copper cobalt oxide is oxidized and reduced prior to oxygen evolution through a reaction involving Co3O4 formation on the surface of cobaltite. (C) 1997 Elsevier Science S.A.