Filtern
Erscheinungsjahr
Dokumenttyp
- Zeitschriftenartikel (52)
- Vortrag (2)
- Sonstiges (1)
- Posterpräsentation (1)
Sprache
- Englisch (51)
- Deutsch (4)
- Mehrsprachig (1)
Schlagworte
- Mechanochemistry (5)
- Nanoparticles (5)
- XRD (5)
- Catalysis (3)
- Alkaline earth metal coordination polymers (2)
- Aluminium (2)
- Brown-rot fungi (2)
- Coordination polymers (2)
- Doped systems (2)
- Fluorides (2)
- Heterogeneous catalysis (2)
- Lewis acid (2)
- Metal fluoride (2)
- Metal fluorides (2)
- Optical properties (2)
- Oxide (2)
- Pyridine (2)
- Quadrupolar nuclei (2)
- Quantitative NMR (2)
- Sol-gel (2)
- Sol-gel process (2)
- Solid state NMR (2)
- Termites (2)
- Wood protection (2)
- XPS (2)
- (NH4)3InF6 (1)
- 1,4-Dimethylpiperazinium chloroferrate(II,III) (1)
- 115In and 19F solid state NMR (1)
- 15N (1)
- 15N NMR (1)
- 27 Al MAS solid state NMR (1)
- 27Al NMR (1)
- 78.20.-e (1)
- 78.66.Li (1)
- 78.68.+m (1)
- 81.20.Fw (1)
- Ab initio structure determination (1)
- Acid site concentration (1)
- Acid surfaces (1)
- Acidity (1)
- Adsorption of pyridine (1)
- Aggregation (1)
- Alkaline earth metal fluorides (1)
- Aluminium fluoride (1)
- Aluminium fluorine (1)
- Aluminium-27 (1)
- Amorphous materials (1)
- Antiferromagnetic coupling (1)
- Au 4f referenced XPS data (1)
- Basidiomycetes (1)
- Bifunctional MgF2 (1)
- Brønsted (1)
- Building-blocks (1)
- Calciumfluorid (1)
- Carbohydrates (1)
- Carbon-fluorine bonds (1)
- Catalysts (1)
- Catalytic activity (1)
- Chemical exchange (1)
- Chemical shift trend analysis (1)
- Chrom (1)
- Colloidal particles (1)
- Coniophora puteana (1)
- Coprecipation (1)
- Core-shell nanoparticles (1)
- Cr2O3 powder (1)
- Crystal Structure (1)
- Crystalline aluminium fluorides (1)
- Crystalline aluminium hydroxy fluorides (1)
- Crystalline aluminium isopropoxide fluoride (1)
- Dispersion (1)
- ESR fine structure (1)
- EXAFS (1)
- Etal-complexes (1)
- Eu (1)
- Europium (1)
- Exchange-coupled units (1)
- FT IR (1)
- FTIR (1)
- Fluoride (1)
- Fluoride catalyst (1)
- Fluoride nanoparticles (1)
- Fluoride xerogels (1)
- Fluorine coordination (1)
- Fluorine coordination polymers (1)
- Fluorolysis (1)
- Fluorolytic sol-gel synthesis (1)
- Fluorolytic sol–gel synthesis (1)
- Fluorolytic sol−gel (1)
- Fluorosulfonic acid (1)
- Functionalization (1)
- Furan derivatives (1)
- Furfural (1)
- Gel synthesis (1)
- Germylium ions (1)
- Gold nanoparticles (1)
- HF (1)
- Halogenometallate (1)
- High field solid state NMR (1)
- High-resolution XPS (1)
- Holzschutzmittel (1)
- Hydrodefluorination (1)
- Hydrofluorination (1)
- Hydroxylated MgF2 (1)
- In situ (1)
- Infrared spectroscopy (1)
- Intramolecular reduction (1)
- Iron coordination (1)
- Kalzienieren (1)
- Katalyse (1)
- Kurvenglättung (1)
- Lanthanides doped coordination polymers (1)
- Lewis (1)
- Lewis-acids (1)
- Lewis/Bronsted (1)
- Lewis/Brønsted acid sites (1)
- Lithium-ion battery (1)
- Luminescence (1)
- Luminescence materials (1)
- Lumineszenz (1)
- MAS NMR (1)
- MAS NMR spectroscopy (1)
- MOF (1)
- MOFs (1)
- MQMAS (1)
- Magnesium (1)
- Magnesium fluoride (1)
- Magnetic susceptibility (1)
- Mechanochemical synthesis (1)
- MgF2 (1)
- Milling (1)
- Mixed valence chloroferrate (1)
- Molar extinction coefficient determination (1)
- Multiplet splitting (1)
- Mössbauer, Raman spectroscopy (1)
- N2-stripping (1)
- NAP-XPS (1)
- NH3-TPD (1)
- NMR (1)
- Nano Particles (1)
- Nano-MgF2 (1)
- Nanopartikel (1)
- Oberflächenanalytik (1)
- Optical layer stacks (1)
- Organic-inorganic hybrid composites (1)
- Oxygen mobility (1)
- Phosphine-ligands (1)
- Photoelektronenspektroskopie (1)
- Polyelectrolytes (1)
- Progressive catalyst poisoning (1)
- Propan oxidation (1)
- Qudrupolar nuclei (1)
- REDOR (1)
- Rhodonia placenta (1)
- Room-temperature (1)
- SEM wood characterization (1)
- Small-angle scattering (1)
- Sol-Gel-Synthese (1)
- Sol-gel synthesis (1)
- Sol-gel-method (1)
- Solid acids (1)
- Solid solutions (1)
- Spektroskopische Charakterisierung (1)
- Spin coating (1)
- Spin-coating (1)
- SrF2 (1)
- Strontium (1)
- Surface analysis (1)
- Surface modification (1)
- Suspensions (1)
- Synchrotron radiation (1)
- TOF (1)
- Terbium (1)
- Thermal decomposition (1)
- TiO2 (1)
- Titanium oxide (1)
- Trigonal-bipyramidal pentachloroferrate(II) (1)
- Ultra high-field MAS NMR (21.1T) (1)
- Vanadium-doped metal oxides (1)
- Vapor-phase hydrofluorination (1)
- Vinyl fluoride (1)
- Water stability (1)
- White-rot fungi (1)
- Wood Protection (1)
- X-ray photoelectron spectroscopy (1)
- XANES-Spektrum (1)
- Xylose (1)
Organisationseinheit der BAM
- 6 Materialchemie (10)
- 6.3 Strukturanalytik (9)
- 4 Material und Umwelt (4)
- 4.1 Biologische Materialschädigung und Referenzorganismen (4)
- 8 Zerstörungsfreie Prüfung (2)
- 8.1 Sensorik, mess- und prüftechnische Verfahren (2)
- 1 Analytische Chemie; Referenzmaterialien (1)
- 1.9 Chemische und optische Sensorik (1)
- 4.3 Schadstofftransfer und Umwelttechnologien (1)
- 5 Werkstofftechnik (1)
Eingeladener Vortrag
- nein (2)
Conventional simultaneous thermal analysis, capillary-coupled TGMS, in situ and ex situ Raman and Mössbauer spectroscopy, as well as chemical analysis have been used for the investigation of the first decomposition step of the mixed valence chloroferrate (dmpipzH2)6[Fe(II)Cl4]2[Fe(III)Cl4]2[Fe(II)Cl5][Fe(III)Cl6]. Under argon at ca. 200°C, an almost complete reduction proceeds in a solid state reaction forming Fe(II). It is accompanied by the release of HCl and, to a minor degree, carbon containing species. A multi-phase product with at least two chloroferrate species, coke, and C,H,N-containing polymers is formed. Binuclear iron complexes, such as (dmpipzH)2[Fe(II)2Cl6], and small amounts of (dmpipzH)[Fe(III)Cl4] have been proposed to be the major and minor component of the product mixture, respectively.
Powder x-ray diffraction (XRD) defined -Al2O3 has been investigated by x-ray photoelectron spectroscopy (XPS) and x-ray excited Auger electron spectroscopy (XAES). The Au 4f7/2 orbital is used for static charge referencing. This feature originates from well-defined and chemically inert 20 nm highly dispersed gold particles deposited on the sample surface. The particles, with a narrow particle size distribution, were obtained from a highly purified colloidal solution (sodium concentration below 1 mg/l). This procedure allows a determination of gold-referenced XPS and XAES data sets. ©2001 American Vacuum Society.
A model regarding the generation of acidity in binary metal fluorides has been proposed and its validity has been examined for several binary fluoride systems with the general compositions MF3/M'F3 and MF2/M'F3. In accordance with this hypothesis, the binary systems (CrF3/AlF3, CrF3/FeF3 and AlF3/VF3) do not show acidities larger than the sum of the acidities of the component fluorides. The hypothesis predicts the generation of Lewis acidity when MF2 is the major component (host) and generation of Brønsted acidity when MF3 acts as the host for the MF2/M'F3. The experimental results (surface acidity and catalytic activity) confirmed the predictions made from this hypothesis for binary combinations MgF2/ M'F3 (M'=Cr, Al, Fe, V). The application of this model is discussed in terms of other parameters: ionic radii and the fluoride affinity of the metal fluorides involved.
The dismutation of CHClF2 to CHF3 and CHCl3 was used to probe the effect of γ-Al2O3 fluorination on fluorine-against-chlorine (Cl/F) exchange reactions. X-ray photoelectron spectroscopy (XPS), X-ray excited Auger electron spectroscopy (XAES) and X-ray absorption near edge structure (XANES) spectroscopy were employed to probe the modifications at the surface of γ-Al2O3 accompanying the initial stages of fluorination. The results suggest that fluorine uptake by γ-Al2O3 starts initially at the surface of the oxide particles, with the formation of a fluorine species that is characterised by a single bond and a high effective charge q. Catalytic Cl/F-exchange is only observed after accumulation of higher fluorine concentrations, for which insertion of fluorine into the sub-surface region of the oxide crystallites has commenced. Quantitative XPS shows that the fluorination level must exceed approximately 10 atom% of the anions to achieve catalytic activity. The spectroscopic evidence suggests that the formation of aluminium oxofluorides is sufficient to provide catalytic activity. The presence of an AlF3 phase is not a condition for the observation of catalytic activity, even though defect-rich AlF3 is ultimately the endpoint of the fluorination process and is itself a Cl/F exchange catalyst.
The 57Fe-Moessbauer spectrum of (dmpipzH2)2[FeIII(H2O)2Cl4][FeIII Cl4]Cl2 (1) consists of two doublets caused by a strongly distorted octahedral and a non-distorted tetrahedral component. Both (dmpipzH2)[FeIIIBr4]2 (2) and (trienH2)[FeIIIBr4]Br (3) show only one doublet indicating a more strongly distorted iron(III) species for 2 and a less-distorted one in the case of 3. For all compounds investigated, the ESR spectra reveal the existence of ground states with predominant antiferromagnetic coupling. The Néel temperatures amount to <4.2 K for 1, 4 K for 3 and 48 K for 2. In the case of 2, both the Moessbauer and the ESR spectra reveal the formation of exchange-coupled {FeBr4} units which has been attributed to a significant cation influence. The fine structure of residual paramagnetic [FeBr4]- subunits remaining in the crystalline matrix could be directly determined. Temperature dependent AC and DC susceptibility measurements of 2 and 3 confirmed the results.
Static TOF-SIMS results strongly underpin earlier conclusions from ESCA, XANES, and tracer studies that the accumulation of fluorine and chlorine at the surface of chromia by a heterogeneous reaction with a chlorofluorocarbon compound results in the formation of mixed chromium oxide halide species and not in the nucleation of CrCl3 and/or CrF3 phases.