Influence of KIT-6’s pore structure on its surface properties evaluated by inverse gas chromatography

The pore structure of mesoporous silica KIT-6 has been systematically tuned via the variation of calcination temperature (773–1223 K), with the mesopore size ranging from 4.8 to 7.5 nm and micropore volume from 0.000 to 0.078 cm3/g, respectively. Four n-alkanes (C6–C9), cyclohexane, benzene, toluene, trichloroethylene, and tetrachloroethylene were employed as probe molecules in the evaluation of the pore structure effect on KIT-6 surface property using inverse gas chromatography (463.2–493.2 K). High free energy of adsorption and enthalpy of adsorption were observed on the KIT-6 with the micropore volumes. The dispersive interaction parameter γSD, and specific interaction parameter ISP, were found to decrease with the increment of the mesopore size of the samples. These results indicate that the occurrence of micropore contributes the adsorption, while the narrow mesopore of KIT-6 promotes the dispersive and specific interaction.

► Pore structure effect on KIT-6 surface property was studied by IGC.
► High adsorption free energy and adsorption enthalpy were observed on KIT-6 with microspores.
► Strong dispersive and specific interaction were found on the samples with the relative narrow mesopores.
► The test molecules were believed to partly penetrate into the minor present micropores.