| Summary: | 碩士 === 臺灣大學 === 環境工程學研究所 === 95 === Motorcycles constitute important parts of air pollution emission in Taiwan. However, only limited studies were focused on the deactivation mechanisms of three-way catalyst converters used in motorcycles.
Furthermore, the performance of deactivated catalyst converters on motorcycles has not been extensively studied. In this study, thermal aging of the catalyst is simulated in laboratory scale. Based on results of
several surface characterization techniques, the effects of aging test exhaust, temperature, and time were examined.
Thermal deactivation mechanism is a combination of several aging phenomena, including sintering of active phase, the collapse in surface area and the thermal deactivation of solid phase. According to the measurement results of specific surface area, XRPD, SEM-EDS, the main mechanism of thermal deactivation is deduced as the collapse in surface area. For all thermal aging operating modes studied, the temperature increase reduced the specific surface area and increased the pore size.
For all thermal aging operating modes studied, light-off curves of aged catalysts were different. The activity test results of 5 hours aged catalysts were differ from others. The results of activity test of during stochiometric and oxidative aging were similar, and the activity indicator,
T75 of during reductive aging catalysts, was lower than the others. The aging temperature and composition of test exhaust are more effective than aging time. The constructed model has good performance on predictions within the thermal aging operating range studied.
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