| Summary: | 博士 === 國立臺灣大學 === 化學工程學研究所 === 99 === Photocatalytic reduction of nitric oxide (NO) was studied over bi-metal loaded TiO2 in a monolith reactor at various temperatures (25, 70 and 120℃). The bi-metal oxide-loaded PdOPtOy/TiO2 photocatalyst, prepared by the thermal hydrolysis method, were used in a continuous system using C3H8 as the reductant. A monolith photoreactor was adopted to provide better light illumination on photocatalyst by using optical fibers, thus the efficiency of photoreaction was improved. The effects such as reductant molar ratio, retention time, light intensity and temperature on the activity of photocatalyst in NO reduction were investigated. Under the optimal reaction condition, C3H8 was able to reduce 89.5% of NO with N2 selectivity 99%. In the presence of O2 and water vapor, 67% and 87% NO conversion can be reached respectively if higher temperature or higher light intensity was used, indicating the adverse effects of O2 and water vapor on NO reduction over PdOPtOy /TiO2 photocatalyst. The intermediates of NO/C3H8 photoreaction were studied with respect to the behavior of adsorbed species on the surface of PdOPtOy/TiO2 using in-situ FTIR. The results indicated that acetone, acetaldehyde, formate and CO species were the intermediates formed during the photoreaction. Neither NCO nor CN was observed during the reaction period. Reaction paths were proposed. The role of NO was to supply oxygen atom for C3H8 oxidation, resulting in the reduction of NO to N2.
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