(99g) Synthesis of Cu-Impregnated MFI Zeolite As Hydrocarbon Adsorbents; The Effective Roles of Cation

In cold start period, hydrocarbon traps adsorb unburned HCs and desorb them in high temperature that three-way catalyst can active. To increase performance of HC trap, we impregnated Cu in MFI zeolite. In Cu-impregnated zeolite, there is Cu⁺ ions inside a MFI zeolite for HC adsorption and CuO particles on the surface for HC oxidation. To study the role of zeolite support, Na-form and H-form zeolite were used as supports. We found the size of CuO particles is different with support. In Cu impregnated Na-form zeolite, large CuO particles were formed on the surface and small CuO particles were formed in Cu impregnated H-form zeolite. Furthermore, Cu-impregnated H-form MFI zeolite have better performance than Cu-impregnated Na-form MFI zeolite. In order to simulate different degrees of long-term driving, the zeolites were hydrothermally treated under various conditions. In addition, we correlate between CST performances of zeolites and the physicochemical properties well. Finally, we also showed the small CuO particles in Cu-impregnated H-form MFI zeolite improve oxidation ability.