@article{41280, author = {{Bauer, Matthias and Bertagnolli, Helmut}}, issn = {{1520-6106}}, journal = {{The Journal of Physical Chemistry B}}, keywords = {{Materials Chemistry, Surfaces, Coatings and Films, Physical and Theoretical Chemistry}}, number = {{49}}, pages = {{13756--13764}}, publisher = {{American Chemical Society (ACS)}}, title = {{{The Amplitude Reduction Factor and the Cumulant Expansion Method:  Crucial Factors in the Structural Analysis of Alkoxide Precursors in Solution}}}, doi = {{10.1021/jp076386i}}, volume = {{111}}, year = {{2007}}, } @article{25987, abstract = {{Mesoporous CeO2 was synthesised by using CMK-3 carbon as a structure matrix. Nitrogen physisorption, powder X-ray diffraction, transmission electron microscopy (TEM), selected-area electron diffraction (SAED), energy-dispersive X-ray (EDX), X-ray absorption near-edge structure (XANES), and thermal (TG/MS) analysis were used for their characterisation. Methanol decomposition to hydrogen, CO, and methane was used as a catalytic test reaction. The obtained products exhibit uniform pores with a diameter of ca. 5 nm in a two-dimensional hexagonal periodic arrangement, as well as interparticle porosity, broadly distributed around ca. 35 nm; the specific surface area is 148 m2 g−1. The pore walls are polycrystalline. The polycrystalline nature and high surface-to-volume ratio of the products is reflected in an increased signal intensity in X-ray absorption spectroscopy. The synthesis of CeO2 from Ce(NO3)3 within the pores of the carbon matrix and the subsequent thermal combustion of the carbon is monitored by thermal analysis. Catalytic tests reveal that the activity of the mesoporous products in methanol decomposition are substantially higher than for a non-porous sample.}}, author = {{Roggenbuck, Jan and Schäfer, Hanno and Tsoncheva, Tanya and Minchev, Christo and Hanss, Jan and Tiemann, Michael}}, issn = {{1387-1811}}, journal = {{Microporous and Mesoporous Materials}}, pages = {{335--341}}, title = {{{Mesoporous CeO2: Synthesis by nanocasting, characterisation and catalytic properties}}}, doi = {{10.1016/j.micromeso.2006.11.029}}, year = {{2007}}, } @article{25986, abstract = {{The authors report the synthesis of nanoporous ZnO, which exhibits a periodically ordered, uniform pore system with crystalline pore walls. The crystalline structure is investigated by x-ray diffraction, transmission electron microscopy, and selected area electron diffraction. The large specific surface area and the uniformity of the pore system are confirmed by nitrogen physisorption. Raman spectroscopy along with low-temperature photoluminescence measurements confirms the high degree of crystallinity and gives insight into defects participating in the radiative recombination processes. The authors thank Günter Koch for recording the TEM images and Marie-Luise Wolff for valuable help in the laboratory one of the authors (M.T.) thanks Michael Fröba for the continuous support.}}, author = {{Waitz, T. and Tiemann, Michael and Klar, P. J. and Sann, J. and Stehr, J. and Meyer, B. K.}}, issn = {{0003-6951}}, journal = {{Applied Physics Letters}}, title = {{{Crystalline ZnO with an enhanced surface area obtained by nanocasting}}}, doi = {{10.1063/1.2713872}}, year = {{2007}}, } @inbook{25990, abstract = {{In-situ X-ray diffraction study on the formation of a periodic mesoporous organosilica material...}}, author = {{Tiemann, Michael and Teixeira, Cilâine V. and Cornelius, Maximilian and Morell, Jürgen and Amenitsch, Heinz and Lindén, Mika and Fröba, Michael}}, booktitle = {{Recent Progress in Mesostructured Materials - Proceedings of the 5th International Mesostructured Materials Symposium (IMMS2006), Shanghai, P.R. China, August 5-7, 2006}}, issn = {{0167-2991}}, title = {{{In-situ X-ray diffraction study on the formation of a periodic mesoporous organosilica material}}}, doi = {{10.1016/s0167-2991(07)80253-9}}, year = {{2007}}, } @article{25988, abstract = {{We report on the synthesis and the gas-sensing properties (CO and NO2 detection) of mesoporous zinc oxide. A two-step structure replication method for the synthesis is employed. In the first step mesoporous SBA-15 silica is prepared by the utilization of self-organization of amphiphilic organic agents. This mesoporous silica is used as the structure matrix for synthesizing mesoporous carbon CMK-3, which, in turn, is employed for yet another replication step, using zinc nitrate as the precursor. The resulting material is characterized by X-ray diffraction and nitrogen physisorption and its gas-sensing properties are compared with a non-porous ZnO sample.}}, author = {{Wagner, T. and Waitz, T. and Roggenbuck, J. and Fröba, M. and Kohl, C.-D. and Tiemann, Michael}}, issn = {{0040-6090}}, journal = {{Thin Solid Films}}, pages = {{8360--8363}}, title = {{{Ordered mesoporous ZnO for gas sensing}}}, doi = {{10.1016/j.tsf.2007.03.021}}, year = {{2007}}, } @article{25985, abstract = {{Semiconducting metal oxides are frequently used as gas-sensing materials. Apart from large surface-to-volume ratios, well-defined and uniform pore structures are particularly desired for improved sensing performance. This article addresses the role of some key structural aspects in porous gas sensors, such as grain size and agglomeration, pore size or crack-free film morphology. New synthesis concepts, for example, the utilisation of rigid matrices for structure replication, allow to control these parameters independently, providing the opportunity to create self-diagnostic sensors with enhanced sensitivity and reproducible selectivity.}}, author = {{Tiemann, Michael}}, issn = {{0947-6539}}, journal = {{Chemistry - A European Journal}}, pages = {{8376--8388}}, title = {{{Porous Metal Oxides as Gas Sensors}}}, doi = {{10.1002/chem.200700927}}, year = {{2007}}, } @inbook{25989, abstract = {{Gas-sensing properties of ordered mesoporous Co3O4 synthesized by replication of SBA-15 silica...}}, author = {{Wagner, Thorsten and Roggenbuck, Jan and Kohl, Claus-Dieter and Fröba, Michael and Tiemann, Michael}}, booktitle = {{Recent Progress in Mesostructured Materials - Proceedings of the 5th International Mesostructured Materials Symposium (IMMS2006), Shanghai, P.R. China, August 5-7, 2006}}, issn = {{0167-2991}}, title = {{{Gas-sensing properties of ordered mesoporous Co3O4 synthesized by replication of SBA-15 silica}}}, doi = {{10.1016/s0167-2991(07)80332-6}}, year = {{2007}}, } @article{41286, author = {{Bauer, Matthias and Gastl, Christoph and Köppl, Christoph and Kickelbick, Guido and Bertagnolli, Helmut}}, issn = {{0026-9247}}, journal = {{Monatshefte für Chemie - Chemical Monthly}}, keywords = {{General Chemistry}}, number = {{5}}, pages = {{567--581}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{EXAFS Spectroscopy of the Alkoxide Precursor Zr(OnBu)4 and its Modification in Solution}}}, doi = {{10.1007/s00706-006-0450-z}}, volume = {{137}}, year = {{2006}}, } @article{41285, author = {{Supplit, R. and Hüsing, N. and Bertagnolli, H. and Bauer, Matthias and Kessler, V. and Seisenbaeva, G. A. and Bernstorff, S. and Gross, S.}}, issn = {{0959-9428}}, journal = {{J. Mater. Chem.}}, keywords = {{Materials Chemistry, General Chemistry}}, number = {{45}}, pages = {{4443--4453}}, publisher = {{Royal Society of Chemistry (RSC)}}, title = {{{Synthesis and characterization of orthorhombic, 2d-centered rectangular and lamellar iron oxide doped silica films}}}, doi = {{10.1039/b606386a}}, volume = {{16}}, year = {{2006}}, } @article{41284, author = {{Liu, Xiong and Bauer, Matthias and Bertagnolli, Helmut and Roduner, Emil and van Slageren, Joris and Phillipp, Fritz}}, issn = {{0031-9007}}, journal = {{Physical Review Letters}}, keywords = {{General Physics and Astronomy}}, number = {{25}}, publisher = {{American Physical Society (APS)}}, title = {{{Structure and Magnetization of Small Monodisperse Platinum Clusters}}}, doi = {{10.1103/physrevlett.97.253401}}, volume = {{97}}, year = {{2006}}, } @article{25993, abstract = {{The growth of ZnS nanoparticles by precipitation from supersaturated aqueous solution is studied by stopped-flow UV absorption spectroscopy. The average size, size distribution, and concentration of the particles are monitored within the sub-second time regime with a resolution of 1.28 ms. Particle growth at these early stages is governed by pronounced ripening. The UV absorption data strongly suggest that growth occurs by preferential adsorption of HS- anions relative to Zn2+ or ZnOH+ cations. Correspondingly, the initial sulfide concentration has a much more pronounced influence on the growth kinetics than the initial zinc concentration. These findings are verified by ζ-potential measurements which confirm that the particle surfaces are negatively charged under near-neutral pH conditions.}}, author = {{Tiemann, Michael and Marlow, Frank and Brieler, Felix and Lindén, Mika}}, issn = {{1520-6106}}, journal = {{The Journal of Physical Chemistry B}}, pages = {{23142--23147}}, title = {{{Early Stages of ZnS Growth Studied by Stopped-Flow UV Absorption Spectroscopy:  Effects of Educt Concentrations on the Nanoparticle Formation}}}, doi = {{10.1021/jp0638383}}, year = {{2006}}, } @article{25992, abstract = {{We report on the synthesis and CO gas-sensing properties of mesoporous tin(IV) oxides (SnO2). For the synthesis cetyltrimethylammonium bromide (CTABr) was used as a structure-directing agent; the resulting SnO2 powders were applied as films to commercially available sensor substrates by drop coating. Nitrogen physisorption shows specific surface areas up to 160 m2·g-1 and mean pore diameters of about 4 nm, as verified by TEM. The film conductance was measured in dependence on the CO concentration in humid synthetic air at a constant temperature of 300 °C. The sensors show a high sensitivity at low CO concentrations and turn out to be largely insensitive towards changes in the relative humidity. We compare the materials with commercially available SnO2-based sensors.}}, author = {{Wagner, Thorsten and Kohl, Claus-Dieter and Fröba, Michael and Tiemann, Michael}}, issn = {{1424-8220}}, journal = {{Sensors}}, pages = {{318--323}}, title = {{{Gas Sensing Properties of Ordered Mesoporous SnO2}}}, doi = {{10.3390/s6040318}}, year = {{2006}}, } @article{25991, abstract = {{Periodically ordered mesoporous magnesium oxide was synthesized in a double replication procedure. Mesoporous SBA-15 silica and CMK-3 carbon were successively used as hard structure matrixes. The carbon pore system was infiltrated with Mg(NO3)2, which was then converted to MgO at 573 K; the carbon matrix was finally removed by thermal combustion. The structure of the mesoporous MgO corresponds to that of the original SBA-15 silica. The products consist of hexagonally arranged cylindrical mesopores and crystalline pore walls. The efficiency of the replication series was studied by variation of the infiltration method and comprehensive pore size analysis of all involved mesoporous materials. The in situ formation of MgO inside the CMK-3 carbon pore system was monitored by thermal analysis. Postsynthetic treatment of the products at 823 K in a vacuum prior to removal of the carbon matrix was found to improve the crystallinity but to diminish the periodic order of the pore system.}}, author = {{Roggenbuck, Jan and Koch, Günter and Tiemann, Michael}}, issn = {{0897-4756}}, journal = {{Chemistry of Materials}}, pages = {{4151--4156}}, title = {{{Synthesis of Mesoporous Magnesium Oxide by CMK-3 Carbon Structure Replication}}}, doi = {{10.1021/cm060740s}}, year = {{2006}}, } @article{41289, author = {{Feth, Martin P. and Bauer, Matthias and Kickelbick, Guido and Metelkina, Olga and Schubert, Ulrich and Bertagnolli, Helmut}}, issn = {{0022-3093}}, journal = {{Journal of Non-Crystalline Solids}}, keywords = {{Materials Chemistry, Condensed Matter Physics, Ceramics and Composites, Electronic, Optical and Magnetic Materials}}, number = {{5}}, pages = {{432--443}}, publisher = {{Elsevier BV}}, title = {{{Influence of additives and post-synthesis treatment on the structural properties of sol–gel prepared alumina-doped zirconia studied by EXAFS-spectroscopy and X-ray diffraction}}}, doi = {{10.1016/j.jnoncrysol.2004.12.012}}, volume = {{351}}, year = {{2005}}, } @article{41287, author = {{Bauer, Matthias and Kauf, Thomas and Christoffers, Jens and Bertagnolli, Helmut}}, issn = {{1463-9076}}, journal = {{Physical Chemistry Chemical Physics}}, keywords = {{Physical and Theoretical Chemistry, General Physics and Astronomy}}, number = {{13}}, publisher = {{Royal Society of Chemistry (RSC)}}, title = {{{Investigations into the metal species of the homogeneous iron(iii) catalyzed Michael addition reactions}}}, doi = {{10.1039/b501204j}}, volume = {{7}}, year = {{2005}}, } @article{25995, abstract = {{The early stages of ZnS nanoparticle growth from supersaturated solution are investigated in situ by stopped-flow UV absorption spectroscopy with a time resolution of 1.28 ms. A model for data analysis is suggested which makes it possible to study both the average particle radius and the concentration. The average radii lie in the sub-nanometer range. During the first 40 ms, growth is predominantly governed by ripening.}}, author = {{Tiemann, Michael and Weiß, Özlem and Hartikainen, Juha and Marlow, Frank and Lindén, Mika}}, issn = {{1439-4235}}, journal = {{ChemPhysChem}}, pages = {{2113--2119}}, title = {{{Early Stages of ZnS Nanoparticle Growth Studied by In-Situ Stopped-Flow UV Absorption Spectroscopy}}}, doi = {{10.1002/cphc.200500163}}, year = {{2005}}, } @article{25994, abstract = {{Periodically ordered mesoporous magnesium oxides were synthesized by utilization of mesoporous CMK-3 carbon as exotemplate. The products exhibit high thermal stability and basic properties, which makes them promising for application in heterogeneous basic catalysis.}}, author = {{Roggenbuck, Jan and Tiemann, Michael}}, issn = {{0002-7863}}, journal = {{Journal of the American Chemical Society}}, pages = {{1096--1097}}, title = {{{Ordered Mesoporous Magnesium Oxide with High Thermal Stability Synthesized by Exotemplating Using CMK-3 Carbon}}}, doi = {{10.1021/ja043605u}}, year = {{2005}}, } @article{41290, author = {{Asthalter, T. and Bauer, Matthias and van Bürck, U. and Sergueev, I. and Franz, H. and Chumakov, A.I.}}, issn = {{1292-8941}}, journal = {{The European Physical Journal E}}, keywords = {{Surfaces and Interfaces, General Materials Science, General Chemistry, Biophysics, Biotechnology}}, number = {{S1}}, pages = {{9--12}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Confined phonons in glasses - A study by nuclear inelastic absorption and Raman scattering}}}, doi = {{10.1140/epjed/e2003-01-003-7}}, volume = {{12}}, year = {{2004}}, } @article{25996, abstract = {{In situ Synchrotron SAXS/XRD Study on the Formation of Ordered Mesoscopic Hybrid Materials with Crystal-Like Walls...}}, author = {{Morell, Jürgen and Teixeira, Cilaine V. and Cornelius, Maximilian and Rebbin, Vivian and Tiemann, Michael and Amenitsch, Heinz and Fröba, Michael and Lindén, Mika}}, issn = {{0897-4756}}, journal = {{Chemistry of Materials}}, pages = {{5564--5566}}, title = {{{In situ Synchrotron SAXS/XRD Study on the Formation of Ordered Mesoscopic Hybrid Materials with Crystal-Like Walls}}}, doi = {{10.1021/cm048453g}}, year = {{2004}}, } @article{41300, author = {{Feth, Martin P. and Bolm, Carsten and Hildebrand, Jens P. and Köhler, Manuela and Beckmann, Oliver and Bauer, Matthias and Ramamonjisoa, Rivo and Bertagnolli, Helmut}}, issn = {{0947-6539}}, journal = {{Chemistry - A European Journal}}, keywords = {{General Chemistry, Catalysis, Organic Chemistry}}, number = {{6}}, pages = {{1348--1359}}, publisher = {{Wiley}}, title = {{{Structural Investigation of High-Valent Manganese–Salen Complexes by UV/Vis, Raman, XANES, and EXAFS Spectroscopy}}}, doi = {{10.1002/chem.200390154}}, volume = {{9}}, year = {{2003}}, }