Regensburg 2010 – wissenschaftliches Programm

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KR: Fachverband Kristallographie

KR 3: Poster: Crystallography in Nanoscience

KR 3.3: Poster

Mittwoch, 24. März 2010, 15:00–17:30, Poster A

Detailed Analysis of the Small Angle X-Ray Scattering of ordered mesoporous titania compounds calcined at different temperatures — •Lars Robben¹ and Adel A. Ismail² — ¹Institut für Mineralogie und ZfM, Leibniz Universität Hannover — ²Institut für Technische Chemie und ZfM, Leibniz Universität Hannover

Small Angle X-Ray Scattering (SAXS) is a powerfull method for the characterization of ordered mesoporous materials (OMMs). OMMs are principially two-phases systems: A material, for example SiO₂ or TiO₂, contains pores with a diameter between 2-50 nm with a regular ordering. The ordering scheme as well as the size and shape of the pores can be controlled by the synthesis conditions. In SAXS experiments the electron density difference between the pores and the material generates Bragg-Reflections which can be used to elucidate the type of crystallographic lattice of the ordering scheme of the pores and to calculate the lattice parameter. An important point with respect to the technical application of TiO₂-OMMs is the crystallinity of the material because a higher crystallinity ensures a better photoactivity for catalytic purposes. Here we present SAXS investigations of TiO₂-OMM calcined at different temperatures and review the assignment of the symmetry group. Furthermore we clarify the main processes which determine the development of the OMM during calcination. Most important in this respect is the interdependency between the crystallinity of the material and the quality (that is the pore shape and the regularity of the lattice) of the mesoporous system.