Bulk and Surface Properties of Copper-Containing Oxides of the General Formula LaZr1-xCuxO3

✍ Scribed by J.A. Anderson; J.L.G. Fierro

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 418 KB
• Volume: 108
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1994.1047

✦ Synopsis

Compounds of nominal composition (\mathrm{LaZr}{1-\mathrm{x}} \mathrm{Cu}{x} \mathrm{O}{3}(0 \leq) (X \leq 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 \mathrm{~K}) and following calcination and reduction at (973 \mathrm{~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, (\mathrm{La}{2} \mathrm{Zr}{2} \mathrm{O}{7}) was obtained. (\mathrm{CuO}) was detected for all values of (X) greater than 0 , whereas (\mathrm{LaCuO}{3}) and (\mathrm{La}{2} \mathrm{CuO}{4}) were only detected for values of (X>0.3). These phases containing copper were reduced within the temperature range (350-800 \mathrm{~K}), leading to formation of metallic copper and (\mathrm{La}(\mathrm{OH}){3}) and (\mathrm{La}{2} \mathrm{O}{3} . \quad 01994) Acaderic Press, Inc.