Mesoporous silicates are attractive materials for catalysis since they can host a variety of metals, and their adjustable pore size allows to control selectivity. Catalytic activity is enhanced by acidity around the metal centers, and the choice of metal influences the degree of acidity. However, understanding the correlation between metal and acidity is difficult due to the complexity of the amorphous structure of these materials. We use multiscale quantum mechanical simulations to investigate structure-property relations in mesoporous silicates doped with various metals. We study the geometrical structure of metals incorporated into the silicate, and the corresponding electron density, which is related to the degree of acidity. We explore various substitution patterns of the metals on amorphous silicate slabs to mimic experimental conditions. We use both a finite cluster approach, and an infinite surface approach through periodic boundary conditions. We consider various metals: e.g., W, Nb, and Zr, for which experimental data on acidity is available. Our results may help improve the experimental design to increase the catalytic activity and lifetime of these materials.

Computational investigation of Lewis acidity in metal-doped mesoporous silicates

251st National Meeting (2016)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.