Structural, Surface, and Catalytic Properties of Aluminas

The published data concerning the structural, surface, and catalytic properties of aluminas are reviewed, and these properties are related to the preparation procedures. The experimental and computational investigations of the structural characteristics of the polymorphs most useful for applications in catalysis, which are γ-, η-, δ-, and θ-Al2O3, are critically analyzed. The thermodynamics of the various polymorphs and the kinetics of the phase transitions are considered. The available information on Brønsted sites (i.e., hydroxyl groups), Lewis acid sites, and acid–base pairs on the surface of aluminas is discussed. Data regarding the application of aluminas as a catalyst and as a catalyst support are summarized. Suggestions for future research are proposed.