Density Functional Theory Study on Catalytic Properties of Metal Oxide Systems: Applications to Acidities of Sulfated Zirconia
Date Issued
2006
Date
2006
Author(s)
Wang, Sheng-Ru
DOI
en-US
Abstract
Density functional theory (DFT) calculations have been performed to investigate chem-
ical and physical properties of mixed metal oxide systems including acidities with sev-
eral models for the sulfated zirconia (SZ) system. It has been proposed that aluminum
promoted SZ have higher catalytic activity and stability on n-butane to iso-butane iso-
merization reaction. The structures and energies of pure, hydroxylated, sulfate adsorbed
and aluminum promoted zirconium oxide were examined based on tetragonal phase using
periodic plane wave and cluster model method, respectively, through di(R)erent models,
sites, functionals and basis sets. The Br?nsted acidities as well as Lewis acidities on dif-
ferent zirconium oxide surfaces were estimated from the vibrational frequencies, charge
distributions, deprotonation energies and ammonia or pyridine adsorption energies to
evaluate the e(R)ects of sulfur and aluminum species. In pyridine adsorptions, the XPS
core-level shifts of N1s were calculated from Kohn-Sham orbital energy di(R)erences. It
was found that the sulfate species plays an important role in elevating Br?nsted acidities
and the aluminum species is used to modify the acid strengths.
Subjects
密度泛函理論
硫酸化氧化鋯
酸性
催化特性
金屬氧化物
Sulfated Zirconia
Acidities
Metal Oxide Systems
Density Functional Theory
Catalytic Properties
Type
thesis