Acidic properties of sulfated zirconia

IR spectroscopy of adsorbed probe molecules (CO, pyridine) is used to chara cterize the acidic properties of sulfated zirconia derived from zirconium o xide acid hydroxide. Their acidic properties are found to be similar. The s trength of the Lewis and Bronsted sites measured by the frequency shift of adsorbed CO is lower than that in zeolites. It is concluded that sulfated z irconia have no superacid Bronsted and Lewis sites. Bronsted sites capable of protonating pyridine vanish when calcining the catalysts at temperature above 773 K, but the strength and concentration of the Lewis acid sites (LA S) do not change.