Cobalt-containing mesoporous silicas—Preparation, characterization and catalytic activity in toluene hydrogenation

摘要

The effect of post synthesis modification was studied on cobalt impregnated mesoporous materials having different textural properties. The supports were SBA-15 and MCM-41 with conventional and spherical morphology. The modified materials were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), temperature-programmed reduction (TPR), FT-IR spectroscopy of adsorbed probe molecules (pyridine and CO) and toluene hydrogenation as a catalytic test reaction. It was found that the amount of surface silanol groups of the mesoporous supports and the variation of the pretreatment procedure have a notable influence on the nature of the cobalt oxide species formed upon the precursor decomposition. Formation of Co3O4, CoO and Co~(2+) species in different ratio, depending on the mesoporous support, was established. The strength of interaction with the support determines the dispersion, reducibility and the catalytic activity in toluene hydrogenation.