Effect of Si/Al ratio on tetralin adsorption on Y zeolite: a DFT study

Probing the adsorption of tetralin on zeolite is of prime scientific and industrial importance with the aim to upgrade the industrial process of tetralin cracking. In this work, the effect of Si/Al ratio ranging from 12 to 39 on tetralin adsorption property on Y zeolite is studied by DFT calculations. Tetralin adsorption on Y zeolite corresponds to a -stacking adsorption mechanism between double bonds of aromatic ring and BrOnsted acid sites. Therefore, the number of BrOnsted acid sites influences the adsorption properties. Lower Si/Al ratio with more BrOnsted acid sites interacting with the aromatic ring of tetralin leads to a higher adsorption energy. Furthermore, the charge and frontier molecular orbital analysis are also performed to understand the influence of Si/Al ratio on adsorption performance. Y zeolite with lower Si/Al ratio shows larger charge difference values and lower HOMO-LUMO gap, which directly manifests the stronger adsorption ability of tetralin and indicates bigger possibility of reacting.