INFLUENCE OF SULFUR-DIOXIDE ADSORPTION ON THE SURFACE-PROPERTIES OF METAL-OXIDES

The effect of SO2 chemisorption at 623 K on various metal oxides (CeO2 , MgO, A1(2)O(3), ZrO2, TiO2 anatase and rutile) has been studied by I R spectroscopy and catalytic tests: cumene cracking and isopropanol de composition. IR spectroscopic studies of lutidine and pyridine adsorbe d on SO2 treated metal oxides surfaces show the increase or the creati on of Bronsted acidity. Test reactions evidence that the strength of s uch sites depends on the metal oxide, being very weak on MgO and impor tant on TiO2. Formation of hydrogensulfite species or modification of the redox character of surface properties explains the SO2 chemisorpti on effects.