Facile Synthesis of KFI-type Zeolite and Its Application to Selective Catalytic Reduction of NO x with NH 3

The small-pore KFI-type zeolite was synthesized via the hydrothermal conversion of zeolite Y with Na + and K + ions without using an organic structure-directing agent (OSDA). The effects of alkali-metal ions and hydroxide ion on the crystallization of KFI were individually investigated by introducing both hydroxide and nitrate salts into synthesis media. The zeolite KFI synthesized under the optimized conditions was copper ion exchanged and then applied for selective catalytic reduction of NO x with an NH 3 (NH 3 -SCR) reaction. Cu-KFI was found to exclusively contain isolated copper ions up to very high loading (Cu/Al 2 = 75%) on the basis of the Cu K-edge extended X-ray absorption fine structure (EXAFS), X-ray absorption near-edge structure (XANES), ultraviolet visible near-infrared spectroscopy (UV–vis–NIR), and temperature-programmed reduction by H 2 (H 2 -TPR) analyses. Interestingl…