| 초록 |
Small pore zeolites have attracted a lot of attention due to improved hydrothermal stability for the selective catalytic reduction of NO with NH3 (NH3-SCR). Especially, high silica zeolite with low aluminum contents of their frameworks is more stable even hydrothermal treatment up to 800 oC. In this work, copper ion exchanged UZM-12 (ERI) with different Si/Al ratios was synthesized through hydrothermal reaction from various gel composition by using the hexamethonium and tetraethylammonium ions as organic structure-directing agents (OSDAs). Their NH3-SCR reaction activities were investigated after hydrothermal treatment at 750 oC which is similar to exhaust gases containing water. NH3-TPD, NO-TPD, H2-TPR analysis results revealed a change of their acidic properties and reactant adsorption abilities. In-situ ESR and in-situ XAFS measurement also provided the change of Cu2+ ion during the NH3-SCR reaction on Cu-UZM-12. |
