Comparative study of Zr, Nb, Mo containing SBA-15 grafted with amino-organosilanes

• All MSBA-15 exhibit acidic properties, but only ZrSBA-15 contains BAS.
• Number of LAS is changed in the following order: ZrS ≫ NbS > MoS.
• Acidity of MSBA-15 and electronic state of metals are important in anchoring of APTMS.
• The binding of amine to metal cations determines the APTMS stability.
• Efficiency of APTMS incorporation increases in the order: ZrS < NbS < MoS.

Transition metals of group IV (Zr), group V (Nb), and group VI (Mo) were introduced into SBA-15 materials during the synthesis towards the production of metallosilicates, MSBA-15, to be used as supports for 3-aminopropyl-trimethoxysilane (APTMS), and 3-[2-(2-aminoethylamino)ethylamino]propyl-trimethoxysilane (3APTMS). The materials obtained were characterized by N2 adsorption/desorption, XRD, TEM, ICP, XPS, UV–Vis, FT-IR and pyridine adsorption. The results indicated that the metals were loaded in the cationic state: Zr4+, Nb5+ and Mo6+ and preferentially located on the SBA-15 surface. The highest efficiency of metal loading in SBA-15 under the conditions used in this work was reached for molybdenum, whereas the highest metal content on the surface was observed for ZrS. The number of Lewis acid sites (LAS) changed in the following order: ZrS ≫ NbS > MoS, whereas their strength as follows: ZrS > NbS ⩾ MoS(HP). Zirconium containing material exhibited additionally BrØnsted acidity. The efficiency of propyl-amine incorporation changed according to the electron state of metals: Zr < Nb < Mo. The binding of propyl-amine to metal cations determined the amine stability.

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