Synthesis and characterization of microspheres composed of SnO2 nanoparticles processed via a chemical route

Abstract SnO 2 microspheres were synthesized by a chemical route, heating the mixed Sn 2+ and sulfuric acid solution in the presence of pressurized oxygen at 900 °C in a designed calorimetric pump. Phase analysis was carried out by X-ray diffraction (XRD) and the results confirmed the SnO 2 microspheres as a single-phase tetragonal structure. Scanning electron microscopy (SEM) images indicated that these microspheres with average diameters of 0.9 μm were composed of SnO 2 nanoparticles with a diameter of about 4.7 nm and a crystallite size of 3.7 nm, as observed by transmission electron microscope (TEM) and calculated by Scherrer's equation from diffractograms, respectively. The formation mechanism of microspheres composed of SnO 2 nanoparticles and the influence of changes in processing are proposed and explained.