| 초록 |
The small-pore KFI-type zeolite was prepared by the hydrothermal conversion of zeolite Y without using organic structure-directing agent (OSDA). The effects of Na+, K+ and hydroxide ion on the formation of KFI were investigated by introducing both hydroxide and nitrate salts into synthesis media. The zeolite KFI synthesized at the optimized condition was copper ion-exchanged, and then applied for selective catalytic reduction of NOx with NH3 (NH3-SCR) reaction. It was found that Cu-KFI catalysts exclusively contain isolated copper ions up to very high loading (~6 wt%) based on the various characterization techniques. Interestingly, Cu-SSZ-13 and Cu-KFI have almost identical activation energy for NH3-SCR reaction, which indicates the presence of similar active sites on both catalysts. After severe hydrothermal aging at 800 °C for 16 h, Cu-KFI substantially maintained structural integrity, which is remarkably stable compared with Cu-Chabazite synthesized from organic-free media. The NH3-SCR activity of Cu-KFI catalyst was comparable to that of Cu-SSZ-13 even after hydrothermal aging. |
