Characterization of nanoporous materials

Correlation between textural and transport properties

The Enke group is engaged in the preparation – synthesis and shaping – of (nano)porous inorganic materials since the beginning of the professorship. For the evaluation of textural properties (specific pore volume, specific surface area, pore width, pore width distribution) classical methods like nitrogen- and argon sorption as well as mercury intrusion porosimetry are used. Permeability investigations allow statements about the mass transport through these monoliths which can then be correlated to the textural data.
Furthermore, these porous materials can be investigated in catalytic test reactions. Therefore, it is useful to have insight into the chemical properties of the materials’ surface. These information can be acquired by inverse gas chromatography and chemisorption.
Also less familiar methods like positron annihilation lifetime spectroscopy (PALS) and 3D-microtomography are used in cooperation with our partners and help to determine open/closed porosity and the pore connectivity.

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Application of nanoporous monoliths

Sensors, host materials, heat insulation, energy storage, catalyst support for environmental catalysis

Beyond fundamental science, especially technical applications for the prepared porous are being ascertained. Particular requirements in sensoric aplications can be satisfied by the monoliths developed in the Enke group, with or without post-synthetic surface modification.
The possibility to tune the materials for the specific application is one of the core competencies.
The particular material systems as well as customized post-synthetic steps open the way to large sized materials for heat insulation and energy storage as well as catalysts and catalyst carriers.
Big efforts are being made especially in the field of environmental and consumer protection.

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Hierarchically structured porous materials

For solving challenges in the field of mass transport limitations, fundamental investigations on the feasibility of introduction of hierarchy into porous materials are being conducted. Such materials are mainly based on SiO2, Al2O3, TiO2, V2O5, CeO2, ZrO2 and their combinations. Hierarchy can be introduced either in „one-pot“-syntheses (using the sol-gel-method) or by targeted subsequent shaping. Thus, hierarchically structured porous monoliths with variable shape can be produced and tailored for particular applications like sensors, catalysts or heat insulators. The transfer into industrially relevant processes is one major field of activity, which starts with development of model systems on the side of material preparation and the testing on the lab scale. This bidirectional feedback allows the optimization of the hierarchical structures in the distinct material systems. These studies serve as a base for the identification of interactions in complex chemical reactions and can lead to economic and ecologic advantages for the industrial applications.

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last modified: 27.05.2015