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. Temperatureprogrammed desorption of ammonia (NH 3 -TPD) and FTIR spectra of pyridine (Py-FTIR) techniques were used to characterize acidity of CeY zeolites. With thiophene (TP, C 4 H 4 S) 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(NO 3 ) 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 sulfurmetal (SÀ 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.[a] Z.

Synthesis of highly active Cu(I)-Y(III)-Y zeolite and its selective adsorption desulfurization performance in presence of xylene isomers

“…It can be observed in Fig. 2a, for Cu(I)-Y, the peaks at 932.7 eV, and 952.6 eV can be attributed to the characteristic of Cu(I) species (Wang et al 2019;Liu et al 2014). While the small peak at 935.3 eV can be assigned to Cu(II) species, indicating that most of the Cu(II) was reduced to Cu(I).…”

“…(Gupta and Paul 2014). Brönsted acid sites were generated due to the dissociation of water in the hydrated metal ions during calcination of metal ions-exchanged zeolites (Mo et al 2019). For Cu(I)-Y, the amount of Lewis acid sites was much more than that of the Brönsted acid sites for all the desorption temperatures, showing that the Lewis acid sites were predominant for Cu(I)-Y (Song et al 2016;Wang et al 2008).…”

“…As environmental awareness grows, deep and ultra-deep removal of sulfur from fuel has become an important global issue (Wang et al 2019). Hydrodesulfurization (HDS) is currently the most common desulfurization method used in the industry (Li et al 2020).…”

Enhanced Adsorption Desulfurization Performance over CuCeY Zeolites Prepared by Low‐Temperature Calcination under H2 Atmosphere

“…[21,38,62,63] The reduction peak at about 390°C assigned to CeO 2 on the surface of CeY zeolite is absent. [21,45] Based on results of literatures, the reduction peaks at 188 and 247°C can be attributed to reduction steps of the Cu 2 + ion species located in the supercage, while at 304°C can be preliminarily attributed to reduction steps of the dehydrated Cu 2 + ion species located in the sodalite cage, respectively. [38,44,63] It is noteworthy that the one-step reduction of CuO + H 2 !…”

“…[38,42] It means that adsorptive capacity of CuCeY zeolite for sulfur compounds has the room for improvement. It may be enhanced by further optimizing preparation conditions CuCeY zeolites, such as using the NH 4 Y zeolite as the raw material and thus increasing the ion exchange degree, [43] altering the Si/Al ratio of Y zeolite, [42] adjusting the pH value [42,44] and concentration [3,38,45] of nitrate solution, changing the temperature and atmosphere of calcination, [3,21,39,46] and enlarging the pore diameter of Y zeolite. [46,47]…”