Coordination state of gallium in MFI structures prepared by direct synthesis and by postsynthetic modification of boralites

The effect of Al3+ coordination structure on the propane dehydrogenation activity of Pt/Ga/Al2O3 catalysts

“…S2(A, B). There is no visible peak for 71 Ga in Ga/C-Al 2 O 3 , indicating that the Ga 3 + ions are in a very low symmetry that causes a very strong electric field gradient at the location of the nuclei [17] . The NMR peak at 0 ppm in Ga/Sg-Al 2 O 3 and Ga/Hd-Al 2 O 3 indicates that Ga 3 + is octahedral-coordinated in these two samples [18] .…”

Effects of crystal size, acidity, and synthesis procedure on the catalytic performance of gallium and aluminum MFI zeolites in glycerol dehydration

“…The first was the synthesis of MFI structures containing gallium or aluminum atoms, in order to tune the strength of the Brønsted acid sites, based on the more basic nature of Ga 3+ , relative to Al 3+ . The substitution of aluminum heteroatoms by gallium decreases the interaction of the metal with the structural oxygen and consequently increases the interaction of oxygen with the proton of the H-MFI zeolite [14,15]. The second aspect was related to differences in the size of the MFI zeolite crystals (produced using different synthesis procedures), in order to show that this parameter influenced the mechanism of glycerol dehydration and the nature of the coke generated.…”

Science and Technology of Framework Metal-Containing Zeotype Catalysts

“…The zeotype material Ga-MFI is a bifunctional material and therefore an effective catalyst for aromatization of light hydrocarbons (76,251). The gallium catalyzes the dehydrogenation of light hydrocarbons, while the acid sites catalyze the aromatization of olefinic species.…”