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 SnO2 by sol-gel method whereas a mixture of tetragonal SnO and orthorhombic SnO2 phases 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 SnO2 nanopowder obtained by the sol-gel method (calcined at 500 degrees C) was estimated to be 11.6 m(2) g(-1), and the mean pore diameter was found to be 6.33 nm. Whereas the mixed SnO/SnO2 sample (calcined at 500 degrees C) obtained by the sonochemical method exhibited a higher surface area of 43.11 m(2) g(-1) and 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.