Tailoring mesoporous silica by functionalization for gases (H2, CH4, CO2) storage applications

In situ functionalized, with different organically groups, mesoporous matrices were generated, starting from silica tetra-alcoxide and functionalized tri- or di-alkoxides, (triethoxyvinylsilan, diethoxy(methyl)vinylsilane and methyltriethoxysilane) mixtures, via sol-gel synthesis. Mesoporous silica matrices have been prepared with the purpose of tailor and optimize their performances as gas storage materials. In this concern, it was designed different experiments to study how the synthesis variables influence the matrix morpho textural properties, being aware that this kind of properties play an important role in the gas adsorption–desorption processes. In order to prepare spherical particles, ammonia was used as catalyst. Eventually, in order to tailor the pore shape and size and implicitly the specific surface area, hexadecyltrimethyl ammonium bromide as directing agent was added, and the molar ratios of organically functionalized precursors/TEOS, were varied. The H2, CH4 and CO2 adsorption properties of prepared functionalized mesoporous silica with different compositions have been studied. In the used experimental conditions, data analysis permits to conclude that the methyl functionalized sample, according to its structural parameters, at 77 K and elevate pressure it showed the best performances concerning the adsorption capacity toward H2 and CO2. CH4 molecules. Toward CH4 molecules, in particular, the analysis performed at room temperature point out that the vinyl- functionalized samples have an appreciable affinity toward this gas specimen.