CATL 34 |
| Recent research1,2 has demonstrated direct photocatalytic oxidation of “soot” by thin films of TiO2. However, little attention has been paid to exploring kinetic models of photocatalyzed soot destruction. We developed earlier3 a series/parallel kinetic model for direct soot oxidation and successfully used it to analyze the experimental CO2 generation data of Mills et al.1 and the soot mass loss data of Lee and Choi2. The model assumed two oxidation pathways: a single step yielding CO2 directly, and a serial sequence through a solid intermediate species, which is subsequently oxidized to CO2. In the present work, laboratory studies of photocatalyzed soot oxidation are conducted using a quartz crystal microbalance (QCM). Soot or a model soot compound is deposited on TiO2-coated quartz crystals. Following each interval of photocatalyzed oxidation, the measured QCM frequency shifts are related to the change in adherent soot mass using the Sauerbrey equation. We test our series/parallel reaction mechanism again to fit our data, and to determine the kinetic model agreement between our experimental work and previous literature1,2. ___________________________________________________________ 1 Mills, A.; Wang, J.; Crow, M. Chemosphere 2006, 64, 1032-1035. 2 Lee, N. C.; Choi, W. Y. J. Phys. Chem. B 2002, 106, 11818-11822. 3 Chin, P.; Roberts, G. W.; Ollis, D. F. Ind. Eng. Chem. Res. submitted, in review |
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Photocatalysis
1:30 PM-4:50 PM, Tuesday, August 21, 2007 BCEC -- 261, Oral
Catalysis & Surface Science Secretariat |