Exploring two green synthesis techniques for nanostructured SnO2 and analyzing material properties for CO and C3H8 gas sensors
摘要
A comparative study on the properties of SnO2 nanoparticles prepared by two sustainable techniques, vigorous agitation (VA) and sonochemical (SCh), was discussed here. The crystallographic planes observed from the XRD patterns are related to the tetragonal crystal structure of SnO2 nanoparticles. The Raman shifts found at 562 and 760 cm−1 are also well-matched with rutile phases of SnO2 (tetragonal crystal structure). The FTIR characteristic peaks at 633 and 533 cm−1 are associated with Sn-O anti-symmetric vibration, confirming the identification of the Sn-O-Sn bond, while other peaks are linked with organic compounds. From SEM and TEM micrographs, SnO2 samples prepared by both techniques contain spherical grains with sizes less than 100 nm, verifying the synthesis of nanoparticles. The diffraction patterns and interplanar distances presented by TEM results are compatible with XRD results. EDS results proved the presence of tin and oxygen elements and their homogenous distribution in the samples. The calculated bandgaps using the Kubelka-Munk plots for SnO2 nanoparticles were 3.70 and 3.74 eV, respectively, using VA and SCh techniques. By analyzing the textural properties, mesoporous materials are noticed where the BET area and pore volume are comparatively higher for SnO2 samples synthesized by the SCh technique than the VA technique. When these synthesized SnO2 nanoparticles were reviewed for sensing CO and C3H8 gases, both VA- and SCh-SnO2 samples contained significant variation of surface electrical resistances operated at temperatures greater than 100