Pyrrole as a Probe Molecule for Characterization of Alkali-Metal-Exchanged ZSM-5: A Combination of a Theoretical and Experimental Study

Abstrakt

The pyrrole interaction with alkali metal ions in ZSM-5 was investigated by IR spectroscopy. The interpretation of the IR spectra at low pyrrole coverages is offered based on the theoretical investigation of this system by the QM-pot method. Two peaks corresponding to N-H stretching vibrations observed experimentally (~90 and ~200 cm^-1, red-shifted compared with gaseous pyrrole) are due to the formation of H-bonds between the pyrrole N-H and framework oxygen atoms of Si-O-Si and Si-O-Al sequences. A very good agreement between experimental and theoretical results was achieved.