Effect of Content of Cerium Ion on Brönsted-Acid-Catalyzed Reaction of Thiophene over CeY Zeolite Studied by In Situ FTIR Spectroscopy

Abstract

With NaY zeolite as the raw material, CeY zeolites with different content of Ce ions were prepared by liquid phase ion exchange (LPIE) method. Their chemical compositions were measured by X-ray fluorescence spectrometry (XRF) and in situ Fourier transform infrared spectroscopy (FTIR) techniques. Temperature-programmed desorption of ammonia (NH3-TPD) and FTIR spectra of pyridine (Py-FTIR) techniques were used to characterize acidity of CeY zeolites. With thiophene (TP, C4H4S) as probe molecule, adsorption and reaction of TP over CeY zeolites were researched by using in situ FTIR spectroscopy. Finally, it can be found that activity of Brönsted(B)-acid-catalyzed reaction of TP firstly increases and then has little change with the increase of concentration of Ce(NO3)3 solution (c), while increases with the increase of the exchange times by a combination of adsorption and reaction of TP over CeY zeolite with acidity of CeY zeolite and with location of Ce ion in CeY zeolite. Especially, the sulfur-metal (S−M) interaction between TP and Ce ion located in the supercage exhibits more influence than B-acid-catalyzed reaction of TP on adsorption desulfurization of CeY zeolite.