Physicochemical Investigations of the Basicity of the Cation Exchanged ETS-10 Molecular Sieves

Abstract

Alkali-metal exchanged M-ETS-10 (M= Li, Na, K, Rb, Cs, and Ba) molecular sieves have been investigated by different techniques such as X-ray diffraction, FTIR, TPD, and XPS. It is found that the overall Lewis basicity in M-ETS-10 increases as the cation is changed from Li to Cs in the alkali cation series. FTIR spectra and TPD of adsorbed CO 2 indicate the presence of different types of adsorbed CO 2 species. XPS studies reveal an increase in the extent of destabilization of O 2p valence levels from Li-ETS-10 to Cs-ETS-10 systems. A strong overlap is observed between Cs 5p and O 2p valence bands. Catalytic activity of Pt supported on M-ETS-10 for n -hexane conversion to benzene increases with the basicity of the support and the same is correlated with the FTIR, TPD, and XPS results.