Synthesis of Nanostructured Tin Oxide by Sol–Gel and Sonochemical Approaches in an Ionic Liquid

The present paper shows a comparative study on the synthesis of nanostructured tin oxide in the ionic liquid 1-ethyl-3-methylimidazolium trifluoromethylsulfonate ([EMIm]TfO) by sol–gel and sonochemical methods. The XRD results of the synthesized materials revealed the formation of single tetragonal phase of SnO2by sol–gel method whereas a mixture of tetragonal SnO and orthorhombic SnO2phases was obtained by the sonochemical method. The sonochemical approach led to the formation of finer nanoparticales with a higher specific surface area than that of the sol–gel synthesized oxide. The average sizes of tin oxide nanoparticles were found to be about 30 nm and 15 nm for the particles obtained by sol–gel and sonochemical methods, respectively. The surface area of SnO2nanopowder obtained by the sol–gel method (calcined at 500 °C) was estimated to be 11.6 m2g−1, and the mean pore diameter was found to be 6.33 nm. Whereas the mixed SnO/SnO2sample (calcined at 500 °C) obtained by the sonochemical method exhibited a higher surface area of 43.11 m2g−1and an average pore diameter of 1.90 nm. The band gap of the synthesized tin oxides was estimated from the UV-vis. results to be 4.01 and 4.25 eV for the sol–gel and sonochemically synthesized samples, respectively.