The effect of SO2 on the adsorption and desorption properties of NO was studied over TiO2-ZrO2, and gamma-Al2O3. The microporous binary oxide, TiO2-ZrO2, exhibited a larae amount of sorptive NOx uptake (ca. 1 mmol g(-1)) at 25 degrees C in the presence and of O-2 SO2. The irreversible chemisorption as nitrate (NO3) is a main cause for the large NO uptake. Desorption of NO, from TiO2-ZrO2 occurred at lower temperature of ca.450 degrees C, compared to >= 500 degrees C required for that from gamma-Al2O3. A similar trend was observed for the SOx desorption, because SO2 adsorbed on gamma-Al2O3 is a stable sulfate-type (SO4), whereas less stable sulfte (SO3) is dominant species on the surface of TiO2-ZrO2. The SOx desorption could further be facilitated in the presence of reducing agents like CO. The thermal swing adsorption/desorption cycle experiment demonstrated that TiO2-ZrO2 can be used as an NOx adsorbent having improved tolerance to SO2. The SO2 tolerance can be explained by the weak basicity of TiO2- ZrO2 and the low activity to oxidize SO2 to form Sulfate species on the surface. (c) 2007 Elsevier B.V. All rights reserved.