Position Control of Catalytic Elements in Zeolites

Abstract

Zeolites have been widely used and industrially applied to various catalytic processes for a long time. The catalytic property of the zeolites strongly depends on various factors including framework type, particle size, and the amount of active site. It has been well-recognized that the heteroatoms isomorphously substituted with Si atoms in siliceous frameworks such as Al, Ga, Fe, Ti, Sn, etc., exhibit unique properties and work as catalytically active sites. Therefore, the location of active sites has to be considered an important factor for catalytic properties, and the control of the crystallographic position, so-called T-sites, of the heteroatoms has extensively been challenged by many research groups. Besides, various types of metal species, cations, clusters, and bulks, have been immobilized in the zeolite. Such metal-containing zeolites have also attracted much attention because they have functioned as solid catalysts for oxidation/reduction processes. Thus, the controls of the chemical states and size of the metal species in zeolite have highly been desired. This chapter introduces our recent research with respect to the “position control of catalytic elements in zeolites” along with their unique catalytic activity owing to the well-controlled position of the catalytic elements.