Solid Acidity on Zeolites and Metal Oxide Monolayers Measured by the Temperature Programmed Desorption of Ammonia

Abstract

Recent progress of solid acidity investigation using temperature programmed desorption (TPD) of ammonia is described with an emphasis of application to the catalytic science and technology. In order to analyze the solid acidity exactly, a water vapor treatment method and theoretical analysis have been developed. Principles on generation of the acidity on zeolites were clarified; one aluminum atom substituting the framework position generates one acid site, and the strength is determined by the crystal structure. The findings on the acidities of metallosilicates and zeolites with extra-framework aluminum species are also introduced. The ammonia TPD was applied to mesoporous solid acids and acidic oxide overlayers covering the surfaces of basic metal oxides in order to clarify the origin of catalytic activity.