Structure elucidation of alkaline earth impregnated MCM-41 type mesoporous materials obtained by direct synthesis: An experimental and theoretical study

• Alkaline earth atoms were embedded into the molecular sieve framework.
• The metal incorporation has promoted the formation of a structure with a center of inversion, active in the Raman.
• The electronic density of oxygen atoms neighbor to the alkaline earth atom has decreased.

In this work, MCM-41 were synthesized hydrothermally and functionalized with calcium and strontium salts by direct method, using the Si/M = 50 molar ratio, in order to elucidate the way as the alkaline earth is incorporated on MCM-41 molecular sieve. The materials were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, nitrogen adsorption–desorption and theoretical calculations by DFT method. Experimental results and computer simulations showed that the alkaline earths were incorporated on MCM-41 through a complex structure, which negatively influences on basic sites formation.

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