Catalysts based on clay and iron oxide for oxidation of toluene

Two samples of heterogeneous catalysts were prepared by impregnating a raw-clay, a montmorillonite-rich material, with iron oxides, in order to be used in oxidative reactions of toluene. The starting clay-sample was collected from a pedon in the region of San Juan, Argentina. All catalysts were characterized with X-ray powder diffraction (XRD), infrared spectroscopy, temperature programmed reduction (TPR), scanning electron microscopy with energy dispersive X-ray analysis (SEM/EDS), and specific surface area measurements. After impregnating the raw clay material with iron oxides, there was a collapse of basal plane spacing and an increase in surface area, from 17 to 62 m2 g−1 of montmorillonite. The TPR, EDS, and XRD results evidenced that the dispersion of iron-containing species depended on how the impregnation was made. The catalyst with higher exposure to iron oxides on sample preparation presented a higher catalytic activity on toluene oxidation.