منابع مشابه
Acidity of two-dimensional zeolites.
Hybrid quantum mechanics:molecular mechanics (QM/MM) calculations of absolute deprotonation energies are performed with periodic boundary conditions for Brønsted sites of aluminosilicate bilayers with various Al/Si ratios (two-dimensional zeolite). The supercell method is applied and density functional theory is used. Much lower values are obtained (1042, 1069 and 1091 kJ mol(-1) for Al/Si = 1/...
متن کاملScaling Relations for Acidity and Reactivity of Zeolites
Zeolites are widely applied as solid acid catalysts in various technological processes. In this work we have computationally investigated how catalytic reactivity scales with acidity for a range of zeolites with different topologies and chemical compositions. We found that straightforward correlations are limited to zeolites with the same topology. The adsorption energies of bases such as carbo...
متن کاملBrønsted activity of two-dimensional zeolites compared to bulk materials.
Different reactivity parameters yield different results for the relative acidity of zeolitic Brønsted sites in thin films and in bulk materials. Whereas the adsorption energies of ammonia and pyridine are about the same, the energy of deprotonation is much lower for two-dimensional systems than for three-dimensional systems. It is shown that this is due to the smaller effective dielectric const...
متن کاملModeling zeolites with metal-supported two-dimensional aluminosilicate films.
Zeolites are one of the most widely used materials in heterogeneous catalysis. However, the current understanding of the relation between structure and reactivity of these complex and highly porous materials mostly comes from studies employing bulk-sensitive techniques and from theoretical calculations based on educated assumptions about the inner surface within the pores present in the framewo...
متن کاملInfrared studies of the surface acidity of oxides and zeolites using adsorbed probe molecules
The use of infrared spectroscopy to probe the surface acidity of oxides and molecular sieves is reviewed. The experimental requirements and the type and nature of probe molecules available are also discussed. Special emphasis is given to the criteria that have to be met to arrive at a characterization of the solid that is useful for its catalytic application.
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ژورنال
عنوان ژورنال: Physical Chemistry Chemical Physics
سال: 2015
ISSN: 1463-9076,1463-9084
DOI: 10.1039/c5cp05088j