Square disks-based crossed architectures of SnO2 for ethanol gas sensing applications-An experimental and theoretical investigation

A facile synthesis and characterization of square disks-based crossed architectures of SnO2 are reported in this paper. The prepared crossed architectures of SnO2 were analyzed by different techniques to study their structural, morphological, crystalline, optical, vibrational and scattering properties. From FESEM analysis an average length of the side and width of the square disks shaped structures were similar to 4-5 mu m and 1.0 +/- 0.2 mu m, respectively. Pure tetragonal rutile phase and crystallite size of 38.26 nm were confirmed by XRD studies. A single welldefined exciton peak at 373 nm corresponding to the energy band gap of 3.33 eV was observed from UV-vis spectrum. SnO2 square disks-based crossed architecture based gas sensor showed gas responses of 70.5, 107.5 and 110.9 at operating temperatures of 350, 400 and 450 degrees C, respectively. The response time of 2 s and recovery time of 2018 s, 1081 s, and 708 s were observed for ethanol gas at 350, 400 and 450 degrees C, respectively. Herein, the interaction between ethanol and SnO2 is simulated by Density functional theory (DFT) calculations. B3LYP/LanL2dz level of theory was employed in this study. It was found that the sensitivity of SnO2 sensor to ethanol molecule may be attributed to the depositing of an oxygen atom from the media to the SnO2 surface.