Characterization of mixed metal oxides (SrTiO3 and BaTiO3) synthesized by a modified aerogel procedure

Nanosized mixed-metal-oxide particles of strontium and barium titanate (SrTiO3 and BaTiO3) were synthesized by a modified aerogel procedure (MAP). The effects on the structural properties of altering the solvent used, calcination temperatures, and calcination parameters were investigated. The aerogels were obtained by supercritical drying of the wet gels from different solvent combinations (mixtures of alcohols and toluene). Depending on the kind of alcohol, the specific surface area and crystallite size of SrTiO3 and BaTiO3 aerogels can be varied. The structural and surface properties were investigated by nitrogen BET analysis, transmission electron microscopy, and powder X-ray diffraction. Comparisons with commercial samples were also made. A mixture of ethanol and toluene was found to be the best binary solvent for supercritical drying, which produced a SrTiO3 sample with a surface area of 159 +/- 9 m(2)g(-1) and an average crystallite size of 8 +/- 2 nm, and a BaTiO3 sample with a surface area of 175 +/- 15 m(2)g(-1) and an average crystallite size of 6 +/- 2 nm. (C) 2004 Elsevier B.V. All rights reserved.