Synthesis, a structural and thermoanalytical study of Ca1-xSrxMoO4 ceramic

For the first time, nano- and micro-sized double-mixed Ca1-xSrxMoO4 (x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 and 1.0) ceramics have been successfully synthesized by an aqueous sol-gel synthesis method in the sol-gel process using tartaric acid as a ligand. An additional novelty of this work was to show the pathways of chemical reactions that occurred under the heat-treatment of the as-prepared Ca–Sr–Mo–O tartrate gel precursors. The structural, morphological, textural and chemical properties of both the tartrate gel precursors and alkaline earth metal molybdates were obtained by thermal analysis (TG/DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy (FT-IR), and RAMAN spectroscopy (RS). The mechanism of thermal decomposition of both the tartaric acid and metal tartrates between all multicomponent Ca1-xSrxMoO4 samples was established and qualitatively compared. Moreover, in support of data from the TGA/DSC curves the quantitative distribution of intermediate products in the gel precursors during the heat-treatment was also estimated. In addition, theoretically determined data of the carbon residues were compared with the corresponding mass change from the TGA curve as a match by suggested reaction mechanism. By combining thermoanalytical investigation with the X-ray diffraction of samples heat-treated at a different temperature the relation of a final composition and its crystallite size with the thermal decomposition process of volatile components was estimated. Scanning electron microscopy was used for both the characterization of surface morphology and estimation of the particle size in the ceramic. FT-IR spectroscopy was applied in order to estimate the possible differences between multicomponent Ca1-xSrxMoO4 systems taking into account the size of crystallites and the nature of surface morphology. Finally, the Raman spectroscopic technique confirmed the initial composition of the elements in the synthesized ceramic and clearly showed that the distribution of both calcium and strontium atoms corresponds to the product, which is composed of a single-phase crystalline compound. [Display omitted] •Sol-gel synthesis of nano- and micro-sized Ca1–xSrxMoO4 ceramics in the sol-gel process using tartaric acid as a ligand.•Thermal decomposition mechanism of Ca–Sr–Mo–O tartrate gel precursors.•Rietveld refinement of the Ca1–xSrxMoO4 system.•SEM analysis of surface morphology of the samples for the Ca1–xSrxMoO4 cer