Comparative Study of Vanadium Supported on MCM-36 and MCM-22 and Their Catalytic Perfomance in C₃-ODH

Abstract

In this work, we report successful preparation of hierarchical V-MCM-36 zeolitic catalyst. Vanadium was introduced onto the zeolite support by impregnation, using vanadyl acetylacetonate as a metal precursor and its subsequent solid state ion exchange during calcination. A conventional three-dimensional V-MCM-22 zeolite was prepared by the same way. Both zeolitic catalysts were characterized by nitrogen adsorption isotherms, X-ray fluorescence, temperature-programmed reduction by hydrogen (H2 -TPR), EPR, FT-IR, diffuse reflectance UV–vis, and Raman spectroscopy. The effect of pillaring and the presence of a combination of micro- and mesopores on catalytic behavior were tested in the oxidative dehydrogenation of propane (C3–ODH) at 540 °C. Obtained results clearly showed that activity of vanadium in zeolitic support is very similar to activity of vanadium in mesoporous silica catalysts. It was also found that hierarchical catalyst is slightly more selective toward propene and exhibits more stable activity than three-dimensional V-MCM-22 catalyst due to a lower rate of carbon deposit formation.

Total Oxidation of Toluene and Propane over Supported Co3O4 Catalysts: Effect of Structure/Acidity of MWW Zeolite and Cobalt Loading

“…MCM-22 is sourced from the ordered layered precursor, MCM-22­(P), and characterized by a unique structure containing two independent pore systems (intralayer two-dimensional 10-member ring (MR) sinusoidal channels and interlayer 10 MR channels accessible to large supercages) . As a solid acid catalyst, MCM-22 has been widely used in various catalytic reactions including cracking, aromatization, and alkylation. , When it is used as a support of catalytically active phases, it showed excellent performance, for example, in the selective catalytic reduction of NO by NH 3 , Fischer–Tropsch synthesis, and propane oxidative dehydrogenation . Recently, Kaminski et al modified MCM-22 with Cu and Au, and the obtained bimetallic catalyst exhibited outstanding performance in the total oxidation of methanol and CO .…”

“…22,23 When it is used as a support of catalytically active phases, it showed excellent performance, for example, in the selective catalytic reduction of NO by NH 3 , 24 Fischer− Tropsch synthesis, 25 and propane oxidative dehydrogenation. 26 Recently, Kaminski et al modified MCM-22 with Cu and Au, and the obtained bimetallic catalyst exhibited outstanding performance in the total oxidation of methanol and CO. 22 Chen et al proved that Y-modified MCM-22 was a good support for PdO x catalysts in toluene oxidation. 27 Importantly, the external surface area of MWW support could be increased by swelling followed by pillaring of MCM-22(P) with amorphous silica, producing MCM-36, which possesses an interlayer mesoporous system and high pore volume.…”

Catalytic Applications of Vanadium: A Mechanistic Perspective

“…Vanadium’s key role in this chemistry is primarily due to its three available oxidation states (+3, +4, and +5). ODH catalysis with vanadium oxide has been investigated over a number of different supports including SiO 2 , , Al 2 O 3 , TiO 2 , ZrO 2 , CeO 2 , NbO 5 , MgO, and zeolites. , While the manner in which vanadia is incorporated onto the support can affect the overall activity and selectivity of the catalyst, in most cases the vanadia has been deposited on the catalyst surface via IWI using a soluble salt (e.g., ammonium metavanadate) as the precursor at or near the pore volume of the support. IWI normally results in a distribution of vanadia sites over the support, including isolated vanadyl species and large V 2 O 5 nanoparticles.…”

Effect of the grafting agent on the structure and catalytic performance of Ti-MCM-22

“…1b) due to condensation of silanol groups and Si-O-Si formation between layers. 44,45 All the grafted samples exhibit the characteristic patterns of calc. MCM-22 with relatively high diffraction intensity, and no TiO 2 phases were detected by XRD (Fig.…”