Isomorphic substitution and postsynthesis incorporation of zirconium into MCM-48 mesoporous silica

Article Abstract:

The isomorphic substitution and postsynthesis introduction of zirconium metal centers into the cubic phase of mesoporous silica are described. The process involves hydrothermal Si/Zr coprecipitation and postsynthesis functionalization of surface silanols with zirconium propoxide. Results from nitrogen sorption and X-ray powder diffraction experiments show that the structure, high surface area and narrow pore size distribution are maintained. Grafting with zirconium propoxide yields the most isolated metal species.

Silica, Metallic oxides, Metal oxides, Substitution reactions, Silicon dioxide, Isomorphism (Crystallography)

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Analysis of the dissociation of H2O in water using first-principles molecular dynamics

Article Abstract:

The electronic, structural and dynamic properties along the reaction path of the dissociation of an H2O molecule in bulk water was analyzed. The dissociation process is composed of four steps, with the last step being effected by a separation of hydromium and hydroxyl ions by two solvation shells. The question of why this species is most often 4-fold coordinated was addressed by the analysis of the electron localization function around the oxygen in the hydroxyl ion.

Analysis, Water, Molecular dynamics, Dissociation, Dissociation reactions, Water analysis

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A density functional theory study of a silica-supported zirconium monohydride catalyst for depolymerization of polyethylene

Article Abstract:

Issues concerning the energetics of a depolymerization reaction on a silica-supported zirconium monohydride are considered. The formation of a three-fold coordinated zirconium monohydrided was found to be more favourable on the (100) surface than on the (111) surface.

Metal catalysts

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