| Summary: | 碩士 === 國立中興大學 === 環境工程學系 === 93 === The object of this research was to investigate the effects of different preparation methods on activity performances of palladium (Pd) catalysts. The Pd catalysts were prepared by sol-gel and impregnation methods, respectively. In the former process, support and Pd active site were synthesized in one step during the sol-gel method; in the latter process, support was synthesized by sol-gel method firstly, and then the coating with Pd active site on its surface with impregnation method. The physical texture and chemical character of Pd catalysts were characterized with BET surface area, X-ray powder diffraction (XRPD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and energy dispersive spectrometer (EDS). The activity performances of Pd catalysts were evaluated by CO oxidation which tested with quartz reactor continuously. Furthermore, the possibility of removing CO and NO simultaneously by Pd catalysts were also investigated.
The results indicated that the catalyst prepared by impregnation method has larger specific surface area than that prepared with sol-gel ones and the crystalline species were little different. However, the particle size of Pd catalysts which prepared by sol-gel method is much smaller than that prepared by impregnation method. Furthermore, the results also exhibited that the Pd catalysts prepared by sol-gel method had higher activity and showed lower activation energy than that prepared by impregnation method. The results might deduce that the Pd catalyst prepared by sol-gel method can improve the dispersion of Pd catalyst and then resulted in high activity.
For removal of CO and NO simultaneously, the results showed that the removal efficiency of NO could be improved by adding CO agent at stoichiometry (CO/NO) equal to 2.5, but this may result in excess of CO.
|
|---|
