Research Highlights 2010

The results of a combined HRTEM and HAADF-STEM study of the complex perovskites NaNb_1-xTa_xO₃ (0.4 ≤ x ≤ 0.6) revealed the formation of extended crystal areas with niobium and tantalum order and allowed us to develop a structural model explaining the experimental findings.

Transmission Electron Microscopy Evidence of Spontaneous B-Cation Layered Distribution in NaNb_1-xTa_xO₃
A. Torres-Pardo, F. Krumeich, J. M. González-Calbet, and E. García-González
J. Am. Chem Soc. 132 (2010) 9843-9849 DOI

Leaching of ZSM-5 Zeolithes

The treatment of ZSM-5 crystals with NaOH leads to an inhomogeneous dissolution with the inner core disappearing more rapidly than the crystal rim (image) indicating an inhomogeneous Al-Si distribution. It could indeed be shown by EDXS mapping that Al is enriched at the rim.

Where are the Active Sites in Zeolites? Origin of Aluminum Zoning in ZSM-5
N. Danilina, F. Krumeich, S. A. Castelanelli, and J. A. van Bokhoven
J. Phys. Chem. C 114 (2010) 6640-6645 DOI

Cytotoxicity of Nanoparticles

The effect of metallic nanoparticles on cells was probed by treating two cell lines with C-coated Cu nanoparticles. The up-take of these nanoparticles was shown by HAADF-STEM that reveal them as bright patches inside the cells (s. image).

Nanoparticle Cytotoxicity Depends on Intracellular Solubility: Comparison of Stabilized Copper Metal and Degradable Copper Oxide Nanoparticles
A. M. Studer, L. K. Limbach, L. Van Duc, F. Krumeich, E. K. Athanassiou, L. C. Gerber, H. Moch, and W. J. Stark
Toxicology Lett. 197 (2010) 169-174 DOI

Structure Determination of Bi₆S₂O₁₅

The reciprocal lattice of a new bismuth oxysulfate was determined by tilting experiments on single crystalline fibers (a=1.221, b=1.961, c=0.584 nm; SG Ccc2). The analogy to Bi₆Cr₂O₁₅ was used to derive a structural model. Simulations calculated with the corresponding parameters and the experimental images match well (see figure; [100] left, [110] right).

Hydrothermal Synthesis of Bi₆S₂O₁₅ Nanowires: Structural, in situ EXAFS, and Humidity-Sensing Studies
Y. Zhou, J.-D. Grunwaldt, F. Krumeich, K. Zheng, G. Chen, J. Stoetzel, R. Frahm, and G. R. Patzke
Small 6 (2010) 1173-117 DOI

Recent Research Hightlights