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 nitra te aqueous solution over conducting glass. Addition of ammonium nitrat e to the sprayed solution increases the crystallization. We report her ein the preparation and characterization of such films using X-ray dif fraction, FTIR reflectance and transmission spectroscopy, W-vis spectr oscopy, scanning electron microscopy, X-ray photoelectron spectroscopy , oxidation power, magnetic and conductimetric measurements. The coppe r ions are distributed over the A and B sites of the inverted spinel l attice and the cobalt ions are postulated to be in the low spin state. Oxide electrochemical stability has been determined by cyclic voltamm etry. Copper cobalt oxide is oxidized and reduced prior to oxygen evol ution through a reaction involving Co3O4 formation on the surface of c obaltite. (C) 1997 Elsevier Science S.A.