Zeolite-supported metal catalysts are widely employed in a number of chemical processes, and the stability catalytically active species is one most critical factors determining reaction performance. A good example Pd/zeolite catalyst, which provides high activity for methane oxidation but deactivates rapidly under conditions due to palladium nanoparticle sintering. Although coating metals with ...

A unidirectional ensemble of hemicyanine molecules was prepared by inserting the molecules into the vertical channels of a uniformly oriented zeolite (silicalite-1) film grown on a glass substrate. Fluorescence from this sample excited with light polarized along the vertical channel was 50 times larger than that excited with light polarized orthogonal to the vertical channel direction. These ve...

We have investigated various silica zeolites using density functional theory with periodic supercells, plane waves, and pseudopotentials. These zeolitic phases include silica sodalite, chabazite, mordenite, silica LTA, and silicalite. Atom-level geometries, elastic properties, and cohesive energies are presented. Although the zeolites exhibit a wide range of Si-O-Si angles and densities, the co...

We present an efficient Monte Carlo algorithm for simulating diffusion in tight-fitting host–guest systems, based on using zeolite normal modes. Computational efficiency is gained by sampling framework distortions using normal-mode coordinates, and by exploiting the fact that zeolite distortion energies are well approximated by harmonic estimates. Additional savings are obtained by performing l...

Implementation of a computer program package for automated collection and processing of rotation electron diffraction (RED) data is described. The software package contains two computer programs: RED data collection and RED data processing. The RED data collection program controls the transmission electron microscope and the camera. Electron beam tilts at a fine step (0.05-0.20°) are combined w...

Adsorption of benzene and p-xylene on silicalite at infinite dilution at 20 "C has been investigated via direct integration and Monte Carlo techniques. A small uncertainty in crystal structure causes a very large difference in the values of the Henry constants, while the internal energy of adsorption is less sensitive to this uncertainty. The sensitivity of the Henry constant to structural deta...