Nature of hydrous zirconia and sulfated hydrous zirconia

Abstract The structure of crystalline hydrous zirconias and their methods of formation are described. A mechanism for the hydrolytic polymerization of Zr IV to obtain the several forms of hydrous oxide is presented. The method by which sulfate ion binds to the surface of zirconia particles is explored. It is concluded that the superacidity of sulfated zirconia arises from the presence of isolated bisulfate groups acting in conjunction with strong adjacent Lewis acid sites. Thus, both Bronsted and Lewis acid sites are present in sulfated oxides.