| Three-Way-Catalysts(TWC) is an effective way to abate CO, HC and NOx in the traffic flue gas simultaneously. However,this type of catalysts is only effective in the narrow range of air to fuel ratio (adjacent to l4.7). Combustion of fuel in the presence of excess oxygen is not only an effective way to improve the fuel utilizing efficiency, but also can decrease the emission of pollutants. However, TWC catalysts exhibit low activity for NOx reduction in these conditions. Metal supported zeolites are considered as one of the promising candidate in this field. Zeolite catalysts must be loaded onto carriers in order to reduce vehicle exhaust resistance. Especially, cordierite (2MgO·2Al2O3·5SiO2) are widely used due to the superior hydrothermal stability, cheap price, plasticity, good washcoat adherence and compatibility with washcoat. In situ hydrothermal synthesis technology is a very simple and workable method in the process of catalyst preparation. The study of in situ synthesis indicates that ZSM-5 can be loaded on the cordierite surface to increase the specific surface area. In spite of meaningful results being obtained, there are some problems to be overcome. For example, the combining properties of molecular sieve layer and carrier, uniformity of the distribution of molecular sieve, the amount of molecular sieve on supports, which are crucial for the application of the monolithic catalysts.In the present thesis, focusing on real applications, zeolites were tightly supported onto ceramic honeycombs by in-situ synthesis and pre-coating sol synthesis. The performance of Cu-ZSM-5/cordierite monolithic catalysts in the abatement of NO in simulated diesel-engine exhaust conditions was explored.Both the weight percentage of monoliths coated and adhesion degree of ZSM-5 onto cordierite were tested. When crystallization time is extended to 60h from 24h and after the monoliths are treated 60 minutes with ultrosonic, the results indicate that the weight of blank cordierite without employing any structuring templates is increased from 2.51% to 13.89% in situ synthesized ZSM-5/cordierite. For the ZSM-5/cordierite made by pre-coating sol synthesis, the weight of blank cordierite is increased from 4.32% to 17.02% with crystallization time of 24h to 60h after the monoliths are treated 60 minutes with ultrosonic.On the basis of the above synthesis, Cu-ZSM-5/cordierite monolithic catalyst is prepared by ion-exchange and impregnation method and applied for the selective catalytic reduction (SCR) of NOx using a simulated diesel exhaust. For the NH3-SCR process, Cu-ZSM-5/cordierite catalyst obtained by ion-exchange methods shows a wide temperature window of maximum activity than those of catalyst prepared only by impregnation method. The conversion rate is closed 100% in the temperature range of 550～750 K. The NO conversion rate will be down with the increase of the GHSV and the oxygen concentration in ambient gases. For the C3H8-SCR process, when the temperature is in the range of 725~895K, the C3H8 conversion rate is almost 100%. But the conversion rate of NO is low, and the highest conversion rate is 50%. The addition of water vapor in the reaction gases has unobvious effect on the conversion of C3H8, but greatly reduces the conversion of NO and the highest conversion rate is less than 40%.
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