Effect of temperature on morphological, optical and electrochemical properties of SnO2 nanoparticles

Pure nanocrystalline SnO2 powders calcined at three different temperatures of 400, 600 and 800°C have been successfully synthesized by chemical co-precipitation method with the starting material SnCl2·2H2O and 2-propanol as a precursor. The crystallite sizes of 10, 12 and 15 nm were obtained for three different temperatures, respectively, and the rutile tetragonal structure was confirmed by XRD pattern. SEM micrographs of all the samples were found to be particulate agglomerated and further crystallite size increases as the temperature increases. The peaks of EDAX reveal that the prepared sample constitutes purely tin and oxide atoms. UV–visible spectra show that the bandgap energy values were 3.05, 3.36 and 3.20 eV. Photoluminescence studies exhibit relative intensity of 422 nm, a small broad peak and somewhat intense peak at 440 nm for the samples annealed at 400, 600 and 800°C. The specific capacitance values of the prepared samples were found to be 380, 335, 548 F g–1 for the samples annealed at 400, 600 and 800°C from cyclic voltammetric studies. Galvanostatic charge–discharge analysis predicts the faradic redox reaction from its symmetric curves.