Synthesis, structure parameter and reaction pathway for spinel-type Co2SnO4

Co2SnO4 powders with the spinel structure were successfully obtained by the sol-gel method using Co(NO3)(2)center dot 6H(2)O and SnCl4 center dot 5H(2)O as raw materials, followed by calcining at 900 and 1500 degrees C for 1 h. Characterization by XRD and SEM showed that at 900 degrees C, crystalline spinel accompanied by Co3O4 and SnO2 is obtained, while at 1500 degrees C homogeneous single-phase spinel powders are synthesized. Analysis by X-ray diffraction (XRD) aided by the refinement method of Rietveld allowed phase quantification and determination of the spine! lattice parameter (8.464 +/- 0.005 A). A reaction pathway is put forward based on a thermal analysis using simultaneous thermogravimetric analysis and differential scanning calorimetry (TGA/DSC). The proposed mechanism suggests that spinel is formed by the reaction between SnO2 (formed from SnCl4) and CoO which in its turn is produced during the decomposition reaction of Co3O4 into CoO and O-2. Co3O4 on the other hand, is formed previously from Co(NO3)(2). (C) 2012 Elsevier B.V. All rights reserved.