Single crystalline SnO2 nanorods functionalized with TiO2 nanospheres and their electrochemical properties

Abstract

Single crystalline SnO2 nanorods coated with TiO2 nanoparticles was synthesised using a two step solvothermal method. The structural and morphological characterizations were done using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The SEM micrographs show that the nanorods are uniformly coated with TiO2 nanoparticles. The elemental composition is determined from the EDAX spectrum. The TEM micrographs reveals that the SnO2 nanorods are single crystalline and formed along (110) direction and breadth wise along (101) direction. The electrochemical properties of both pure SnO2 and SnO2-TiO2 nanocomposite were investigated using cyclic voltammetry and electrochemical impedance spectroscopy, indicating that the chemical changes occurring at the electrode surface is a coupled reaction involving electron transfer followed by a reversible chemical reaction. The high reversibility and hence pseudocapacitive behaviour is confirmed as there is no significant shift in the anodic and cathodic peak currents with increasing scan rate. The slope of the plot of log i versus log v is varying from 0.9 to 1 further confirming excellent pseudocapacitance. A significant increase in the specific capacitance is observed for SnO2-TiO2 nanocomposite compared to pure SnO2.