| 초록 |
High siliceous small pore zeolite, chabazite, containing copper has been drawn much attention due to high thermal stability at 1023 K and exceptional catalytic performance in selective catalytic reduction of NO using ammonia. However, the catalytic activity is significantly deteriorated when the catalyst is subject to hydrothermal aging at 1173 K or more under 10% water. Therefore, there have been numerous efforts to improve the thermal stability. In this work, in order to investigate the controlling factor for thermal stability, high siliceous chabazite of which the Si/Al2 ratio was 24 has been prepared using various organic structure directing agents through direct hydrothermal conversion of ultrastable Y zeolite. The hydrothermal stability of the catalyst was found to be controllable with the Si/Al ratio, the counter cation presented in the zeolite and zeolite crystal size, which was also resulted in the dramatic change of catalytic performance in NH3-SCR reaction. |
