Trimethylamine sensing properties of thorium-incorporated tin oxide

We report the trimethylamine (TMA) sensing properties of thoria-incorporated tin oxide. The tin oxide pellet having 3 wt.% of thoria exhibits a high sensitivity of 1500 towards 800 ppm of TMA compared to only 18 of pure tin oxide at a lower operating temperature of 225 °C. The incorporation of thorium in tin oxide enhances the sensitivity towards TMA with improved selectivity. The effect of surface coverage, morphology and oxidation state on the sensitivity has been studied using techniques like scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The correlation between thoria incorporation in the tin oxide at different sintering temperatures and the improvement in the selectivity and sensitivity towards TMA is discussed.