Structural, electronic and bonding properties of zeolite Sn-Beta: A periodic density functional theory study

TL;DR

This study uses periodic density functional theory to analyze how tin substitution affects the structure, electronic properties, and bonding in Sn-BEA zeolite, identifying the most favorable T-site for Sn incorporation.

Contribution

It provides a detailed computational analysis of Sn substitution in BEA zeolite, highlighting the most energetically favorable sites and the impact on electronic properties.

Findings

Sn substitution is endothermic and limited by energetics.

T2 site is most favorable for Sn incorporation.

LUMO energies correlate with Lewis acidity.

Abstract

The structural, electronic and the bonding properties of the Sn-BEA are investigated by using the periodic density functional theory. Each of the 9 different T-sites in the BEA were substituted by the Sn atom and all the 9 geometries were completely optimized using the plane wave basis set in conjunction with the ultra-soft pseudopotential. On the basis of the structural and the electronic properties, it has been demonstrated that the substitution of the Sn atom in the BEA framework is an endothermic process and hence the incorporation of the Sn in the BEA is limited. The lowest unoccupied molecular orbitals (LUMO) energies have been used to characterize the Lewis acidity of each T-site. On the basis of the relative cohesive energy and the LUMO energy, T2 site is shown to be the most favorable site for the substitution of Sn atom in the BEA framework.