Molecular dynamics investigation of structural properties of a zeolite ZSM-5 based amorphous material

Abstract

Results of molecular dynamics simulations on structural properties of zeolite ZSM-5 based amorphous solids are presented. The topology of the network is analyzed by pair-distribution functions, bond angle distributions, and coordination number distribution. The effects of the extent of amorphization, measured by an energetic criterion, on properties like the distribution of coordination numbers, internal surface area, ring statistics, and effective pore size are studied. Analysis of the amorphized systems further reveals that due to the partial collapse of the zeolite framework, the porosity and internal surface area for large and small substrates are reduced and increased, respectively, possibly allowing a design of material with specific desired catalytic properties. Ring statistics indicates that upon amorphization not only rings with larger size break down to give rings with smaller size, but that for intermediate degree of amorphization also larger rings are generated.