Acidity Generation of Binary Metal Oxide Catalysts

Abstract

Publisher Summary From a practical and theoretical point of view concerning binary metal oxides, it is important to find oxide combinations that have well-defined acid or basic properties. On a catalytic oxide surface, the acidic or basic sites can be either too strong, causing some irreversible adsorption of the species, or too weak to activate the reactants. Therefore, the possibility to regulate the acid–base strength of oxide surfaces appears as a necessary tool in catalytic purposes. The acid–base strength can be enhanced or decreased by the addition of a secondary component that modifies the electronic and geometric characteristics of the active sites. The study given in the chapter determines the acid–base properties of simple oxides by adsorption calorimetry of acid and basic probe molecules, such as ammonia and sulfur dioxide. The chapter also extends this study to the characterization of binary oxides with various acidic and basic additive ions to rationalize the mechanism of acidity generation in binary oxide compositions.