Semiconducting SnO2-TiO2 (S-T) composites for detection of SO2 gas

Abstract

SnO 2 -TiO 2 (S-T) composites with different molar ratios were prepared by mechanical mixing followed by sintering at 700°C for 4 h in air. The structural and microstructural properties of the composites were investigated using powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM). S-T composites were investigated by introducing SO 2 to test their chemical stability using PXRD and SEM coupled with energy dispersive X-ray (EDX) analysis. The sensing performance was measured at different temperatures using various SO 2 concentrations (10-100 ppm). A composite comprising 25 mol% of SnO 2 and 75 mol% TiO 2 (S25-T75) exhibited the highest sensitivity comparing to other S-T composites studied under the presently investigated conditions. t 90 (90 % of response time) was found to be ∼5 min for thick pellet (~2 mm in thickness). SO 2 sensing mechanism has been explained through the band structure model.

Using a Photoacoustic Cell for Spectroscopy of Toxic Air Pollutants including CO2, SO2 and NO Gases

“…The typical concentration of SO 2 in industrial exhaust is at the ppm level (particle per molecule). However, SO 2 has considerable impacts on environmental pollution (e.g., acid rain) [8].…”