XPS VALENCE BAND STUDY OF ZEOLITES AND RELATED SYSTEMS .1. GENERAL-CHEMISTRY AND STRUCTURE

The first detailed, reproducible, experimental results are presented of the valence band spectra of a variety of commercially important zeolites. These were obtained using X-ray photoelectron spectroscopy (XPS or ESCA). A general chemical formulation of (SiO2)x &middot(M+p1/pAlO-2)y&middotZH2O applies to the materials examined, where, for most of the cases studied, M+p=Na+. Comparisons are made with well-known experimental and theoretical (MO and band structure) results for various silicas and aluminas. Numerous interrelationships are found involving most of the key subband features documented for the latter materials. Distinct shifts and truncations are found in the zeolite bands. These suggest that zeolites more closely depict an agglomeration than a persistent type mixture of the aforementioned precursors.