Application of computer modelling to the mechanisms of synthesis of microporous catalytic materials

Abstract

We present results of a study of species present during the hydrothermal synthesis of zeotype materials. We have studied the interactions of typical silica fragments, which condense to form the framework structure, with both solvent (water) and the organic molecules used as structure-directing agents. The hydrophobic nature of the fragments results in the collapse of the fragment structure on solvation, resulting in geometries far removed from their configuration in the crystalline material. The presence of the organic template provides stabilisation for the hydrated fragments, effectively shielding them from the water and allowing them to maintain their open structure. The impact of these results on possible mechanisms of crystallisation is discussed.