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End date: 2019 × Start date: 2016 × DDC: 540 × Type: article × Sponsor: Leibniz_Fonds ×

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Now showing 1 - 3 of 3
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    Nb-modified Ce/Ti oxide catalyst for the selective catalytic reduction of NO with NH3 at low temperature
    (Basel : MDPI, 2018) Mosrati, Jawaher; Atia, Hanan; Eckelt, Reinhard; Lund, Henrik; Agostini, Giovanni; Bentrup, Ursula; Rockstroh, Nils; Keller, Sonja; Armbruster, Udo; Mhamdi, Mourad
    Recently, great attention has been paid to Ceria-based materials for selective catalytic reduction (SCR) with NH3 owing to their unique redox, oxygen storage, and acid-base properties. Two series of bimetallic catalysts issued from Titania modified by Ce and Nb were prepared by the one-step sol-gel method (SG) and by the sol-gel route followed by impregnation (WI). The resulting core-shell and bulk catalysts were tested in NH3-SCR of NOx. The impregnated Nb5/Ce40/Ti100 (WI) catalyst displayed 95% NOx conversion at 200 °C (GHSV = 60,000 mL·g−1·h−1, 1000 ppm NOx, 1000 ppm NH3, 5% O2/He) without forming N2O. The catalysts were characterized by various methods including ICP-OES, N2-physisorption, XRD, Raman, NH3-TPD, DRIFTS, XPS, and H2-TPR. The results showed that the introduction of Nb decreases the surface area and strengthens the surface acidity. This behavior can be explained by the strong interaction between Ceria and Titania which generates Ce-O-Ti units, as well as a high concentration of amorphous or highly dispersed Niobia. This should be the reason for the excellent performance of the catalyst prepared by the sol-gel method followed by impregnation. Furthermore, Nb5/Ce40/Ti100 (WI) has the largest NH3 adsorption capacity, which is helpful to promote the NH3-SCR reaction. The long-term stability and the effect of H2O on the catalysts were also evaluated.
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    1,1-Bis(di­phenyl­phosphor­yl)hydrazine
    (Chester : International Union of Crystallography, 2018) Höhne, Martha; Aluri, Bhaskar R.; Spannenberg, Anke; Müller, Bernd H.; Peulecke, Normen; Rosenthal, Uwe
    The title compound, C24H22N2O2P2, contains a diphosphazane backbone, as well as a hydrazine entity. The P—N—P diphosphazane unit and the N-amine N atom are almost coplanar, and the O atoms of the Ph2P(O) units are oriented trans to each other with respect to the P...P axis. In the crystal, centrosymmetrically related mol­ecules are linked into dimers by pairs of N—H...O hydrogen bonds, forming rings of graph-set motif R22(10).
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    Silica nanoparticles for intracellular protein delivery: A novel synthesis approach using green fluorescent protein
    (London : BioMed Central, 2017) Schmidt, Sarah; Tavernaro, Isabella; Cavelius, Christian; Weber, Eva; Kümper, Alexander; Schmitz, Carmen; Fleddermann, Jana; Kraegeloh, Annette
    In this study, a novel approach for preparation of green fluorescent protein (GFP)-doped silica nanoparticles with a narrow size distribution is presented. GFP was chosen as a model protein due to its autofluorescence. Protein-doped nanoparticles have a high application potential in the field of intracellular protein delivery. In addition, fluorescently labelled particles can be used for bioimaging. The size of these protein-doped nanoparticles was adjusted from 15 to 35 nm using a multistep synthesis process, comprising the particle core synthesis followed by shell regrowth steps. GFP was selectively incorporated into the silica matrix of either the core or the shell or both by a one-pot reaction. The obtained nanoparticles were characterised by determination of particle size, hydrodynamic diameter, ζ-potential, fluorescence and quantum yield. The measurements showed that the fluorescence of GFP was maintained during particle synthesis. Cellular uptake experiments demonstrated that the GFP-doped nanoparticles can be used as stable and effective fluorescent probes. The study reveals the potential of the chosen approach for incorporation of functional biological macromolecules into silica nanoparticles, which opens novel application fields like intracellular protein delivery.