A Colombian bentonite was modified by intercalation with polyhydroxocationic solutions of Al3+ containing Fe3+ and Ce3+. Addition of these solutions led to the formation of pillared clays with important catalytic properties in three environmental impact reactions: phenol oxidation in diluted aqueous medium, oxidation of CO and 2-propanol oxidation in gas phase. The catalytic tests revealed the activity of the introduced iron species and the promoter effect of the cerium on the catalytic activity of these species. X-ray diffraction and the transmission electron microscopy results indicated, respectively, the formation of oxide nanoparticles inside and outside of the interlayer spaces of the clay mineral structure. Mossbauer spectroscopy analysis revealed the presence of iron oxides with oxidation state +3 and hematite structure on the solids. (c) 2006 Elsevier B.V. All rights reserved.