Effect of Ionic Liquids on the Structural Properties of SBA-15/CeO₂ Nanocomposites

Ordered mesoporous silica materials have attracted considerable attention due to their unique structural, textural, and morphological properties, alongside their versatile applications in catalysis, adsorption, and drug delivery systems. This study explores the influence of ionic liquids (ILs) on the synthesis of SBA-15 and SBA-15/CeO₂ nanocomposites. DMIBr (1-dodecyl-3-methylimidazolium bromide) and DMIBF₄(1-dodecyl-3-methylimidazolium tetrafluoroborate) were the analyzed ILs. The objective was to evaluate how these ILs modulate the structural, textural, and morphological properties of the resulting nanocomposites. SAXS analysis confirmed the formation of well-ordered mesoporous structures with hexagonal arrangements, corroborating with physisorption data and TEM images. XRD measurements confirmed the presence of CeO₂ nanoparticles within the nanocomposites, exhibiting a fluorite-type cubic crystal structure, supported by Raman spectroscopy, which identified characteristic peaks corresponding to Ce-O vibrational modes. XPS analysis provided detailed insights into the surface chemistry, revealing the presence of Ce³⁺ and Ce⁴⁺ ions, oxygen species, and their interaction with the silica matrix. The Ce³⁺ ions, associated with oxygen vacancies in the CeO₂ lattice, were identified as key active sites for adsorption and catalysis. SEM images displayed distinct morphologies of the nanocomposites, attributed to the specific used IL. These results underscore the pivotal role of ILs in tailoring the properties of SBA-15/CeO₂ nanocomposites, offering valuable knowledge for their potential applications in diverse fields.