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Abstract: A series of MoO3–ZrO2 nanocomposite oxides with MoO3 content in the range of 2–20mol% were prepared by solution combustion method. Three different fuels namely urea, glycine and hexamethylenetetramine (HMTA) were used for the preparation of MoO3–ZrO2 oxides. For the sake of comparison, the MoO3–ZrO2 composite oxides were also prepared by impregnation of zirconia with molybdenum salt precursor and subsequent heat treatment. The synthesized nanomaterials were characterized by XRD, SEM, TEM and UV–vis spectroscopic technique. XRD study indicated selective stabilization of the tetragonal phase of zirconia in the presence of MoO3. The method of preparation was found to be crucial for the phase composition of zirconia in the composite oxide. The crystallite size and rms stain were calculated from the Fourier line shape analysis of the broadened X-ray diffraction profiles. With increase in the MoO3 content, the crystallite size of the tetragonal zirconia phase was found to be decreased. TEM study indicated the presence of small nanoparticles with size in the 5–10nm range. UV–vis study of the composite oxide materials revealed well dispersion of the molybdenum oxide component in the form of monomer, dimers and nanoclusters in the zirconia matrix. The nature of fuel was found to be crucial in determining the morphology and shape of the particles. [Copyright &y& Elsevier]

Abstract: Ultra-fine Al2O3 fibers were synthesized via electrospinning technique using PVP/ethanol polymer solution and aluminium acetate sol followed by calcinations at higher temperature. The formation, crystalline phase, surface morphology, fibers diameter and surface area of alumina ultra-fine fibers were characterized using FT-IR, TGA/DTA, XRD, SEM, TEM and BET analytical techniques. The results show that pure and crystalline α-Al2O3 ultra-fine fibers were formed with fiber diameter in the range of 100–500nm and BET surface area of the fibers were found to be 40m2/g. [Copyright &y& Elsevier]