Aqueous sol–gel synthesis, thermoanalytical, structural and vibrational studies of lithium aluminium molybdate (LiAlMo2O8)

Abstract

Aqueous tartaric acid-assisted sol–gel preparation technique was successfully applied to synthesise lithium aluminium molybdate with the initial composition of LiAl(MoO4)2. From the results of the thermal analysis and Xray diffraction measurement, the effect of tartaric acid as a ligand on the formation of homogeneous gel precursor was discussed. Besides, X-ray diffraction also revealed the crystallisation of the final LiAlMo2O8 ceramic below the temperature of 400°C. It was found that the initial composition of obtained ceramic significantly affected the formation of the impurity phase defined as AlMo2O12. The Rietveld refinement of the crystalline samples showed the tendency of crystallites growing with the increase of heat-treatment temperature. Similar trends of particle growing were also observed in the images of scanning electron microscopy (SEM) for the corresponding samples heat-treated at different temperatures. Finally, the Fourier-transform infrared spectroscopy (FT-IR) revealed the effect of both the surface morphology and the crystallite size on the intensity of characteristic vibration of the corresponding chemical bonds.