BULK AND SURFACE-PROPERTIES OF COPPER-CONTAINING OXIDES OF THE GENERAL FORMULA LAZR1-XCUXO3

Compounds of nominal composition LaZr1-xCuxO3 (0 ≤ X ≤ 1) have been prepared by thermal decomposition in air of precursors prepared by the amorphous citrate method. X-ray diffraction has been used to determine the phases present in the material following calcination at 973 K and following calcination and reduction at 973 K. X-ray photoelectron spectroscopy (XPS) was used to obtain information regarding electronic state and concentration of elements in the surface layers, while thermal gravimetric (TG) studies in hydrogen indicate the relative stability of copper species towards reduction. For all values of X except 1, the pyrochlore phase, La2Zr2O7 was obtained. CuO was detected for all values of X greater than 0, whereas LaCnO3 and La2CuO4 were only detected for values of X < 0.3. These phases containing copper were reduced within the temperature range 350-800 K, leading to formation of metallic copper and La(OH)3 and La2O3. © 1994 Academic Press, Inc.