Abstract: Dehydration-nitridation method is employed to prepare nitrogen-incorporated HY zeolites. High crystallinity and specific surface area of parent HY are well preserved in nitrogen-incorporated HY zeolites. The base strength of HY framework is enhanced due to the replacement of oxygen by nitrogen with lower electronegativity. The acidity and basicity of nitrogen-incorporated HY zeolite are characterized by IR spectra using NH3 and CO2 as probe molecules and temperature-programmed desorption of CO2. The amounts of L-acid sites decrease, while the amount of L-acid sites and base sites increase after nitridation. Moreover, new base sites with moderate strength are created after nitridation. Compared to parent HY zeolite, the nitridized sample exhibits improved basic catalytic performance in Knoevenagel condensation reaction.

Key words: HY, Dehydration, Nitridation, Acidity, Basicity