Preparation, characterization and performance of tio2 based catalytic pellet for detection of volatile organic compound under UV light

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dc.contributor.authorJuhari, Jusliha
dc.date.accessioned2014-11-03T02:11:44Z
dc.date.available2014-11-03T02:11:44Z
dc.date.issued2009
dc.descriptionMasteren_US
dc.description.abstractNowadays, environmental regulations on volatile organic compounds (VOCs) have been tightened all over the world, as their rapid evaporation and toxic or carcinogenic nature at high concentrations in the air make them dangerous to human beings. Accordingly, in order to detect dangerous and toxic VOCs, high performance gas sensors made up from low cost materials and simplicity in fabrication are required to measure various kinds and quantities of VOCs. In the present study, a sensing material (La-modified TiO2/ Sn-modified TiO2) was developed by incorporating lanthanum (La) or tin (Sn) onto TiO2-based material by sol-gel method in different orders with additive loadings range between 0.0 at.% and 10.0 at.% and calcination temperatures range between 500 °C and 900 °C, respectively. Then, the sensing material was pressed into a catalytic pellet with a diameter of 20 mm and a thickness of 2 mm. The sensing materials (powders and catalytic pellets) were characterized using thermal gravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscopy (TEM), surface analysis (N2 adsorption-desorption), scanning electron microscope (SEM) and energy dispersive X-ray (EDX) spectroscopy. The detection activity was performed in a measurement chamber with heating facilities operated at temperatures between 50 °C and 400 °C. The performance of selected catalytic pellet under various operating conditions was further studied with different concentrations of VOC vapor (ethanol, methanol and acetone) between 1000 ppm and 3000 ppm under the influence of UV light irradiation. Based on the detection performance and characterization study, the best result was obtained when TiO2 was modified with Sn additive while the optimum loading of Sn and calcined temperature was 2.5 at.% and 600 °C, respectively. The performance of selected catalytic pellet (2.5-Sn-TiO2-600) under various operating conditions was at the optimum when operating temperature was at 250 C with the highest sensitivity of ~ 38.12 for 3000 ppm of ethanol vapor detection. The sensitivity of the catalytic pellet was greatly enhanced by the UV light irradiation to sensitivity values of ~ 73.57, while reducing the optimum operating temperature to 200 C. The gas-sensing mechanism of the catalytic pellet was found to be a surface-controlled type and the electrical resistance-temperature characteristic indicated an n-type semiconductor. In conclusion, the 2.5-Sn-TiO2-600 catalytic pellet was a suitable pellet sensor for the VOC detection under UV light irradiation due to the low cost materials used and eases of fabrication with high VOC sensitivity even at lower operating temperature.en_US
dc.identifier.urihttp://hdl.handle.net/123456789/226
dc.language.isoenen_US
dc.subjectChemical scienceen_US
dc.subjectCatalytic pelleten_US
dc.subjectVolatile organic compounden_US
dc.subjectUV lighten_US
dc.titlePreparation, characterization and performance of tio2 based catalytic pellet for detection of volatile organic compound under UV lighten_US
dc.typeThesisen_US
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