The interlayer space of K0.8Fe0.8Ti1.2O4 was expanded by SiO2-pillaring. The length of the interlayer spacing and surface area were increased by pillaring from 0.78 to 1.98 nm and from 0.4 to 154 m(2) . g(-1), respectively. N-2 adsorption on the SiO2-pillared K0.8Fe0.8Ti1.2O4 was studied by infrared (IR) spectroscopy. Two types of adsorbed N-2 were observed at 2330 and 2350 cm(-1). The former showed ordinary adsorption on oxides (Delta H-a = ca. 1 kcal/mol) and the latter indicated activated adsorption (Delta H-a = ca. 6 kcal/mol), where migration into the pillared interlayers is considered to be the rate-determining step.