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- ItemPentacene in 1,3,5-Tri(1-naphtyl)benzene: A Novel Standard for Transient EPR Spectroscopy at Room Temperature(Wien [u.a.] : Springer, 2021) Schröder, Mirjam; Rauber, Daniel; Matt, Clemens; Kay, Christopher W. M.Testing and calibrating an experimental setup with standard samples is an essential aspect of scientific research. Single crystals of pentacene in p-terphenyl are widely used for this purpose in transient electron paramagnetic resonance (EPR) spectroscopy. However, this sample is not without downsides: the crystals need to be grown and the EPR transitions only appear at particular orientations of the crystal with respect to the external magnetic field. An alternative host for pentacene is the glass-forming 1,3,5-tri(1-naphtyl)benzene (TNB). Due to the high glass transition point of TNB, an amorphous glass containing randomly oriented pentacene molecules is obtained at room temperature. Here we demonstrate that pentacene dissolved in TNB gives a typical “powder-like” transient EPR spectrum of the triplet state following pulsed laser excitation. From the two-dimensional data set, it is straightforward to obtain the zero-field splitting parameters and relative populations by spectral simulation as well as the B1 field in the microwave resonator. Due to the simplicity of preparation, handling and stability, this system is ideal for adjusting the laser beam with respect to the microwave resonator and for introducing students to transient EPR spectroscopy. © 2021, The Author(s).
- ItemPinning of the Fermi Level in CuFeO2 by Polaron Formation Limiting the Photovoltage for Photochemical Water Splitting(Weinheim : Wiley-VCH Verlag, 2020) Hermans Y.; Klein A.; Sarker H.P.; Huda M.N.; Junge H.; Toupance T.; Jaegermann W.CuFeO2 is recognized as a potential photocathode for photo(electro)chemical water splitting. However, photocurrents with CuFeO2-based systems are rather low so far. In order to optimize charge carrier separation and water reduction kinetics, defined CuFeO2/Pt, CuFeO2/Ag, and CuFeO2/NiOx(OH)y heterostructures are made in this work through a photodeposition procedure based on a 2H CuFeO2 hexagonal nanoplatelet shaped powder. However, water splitting performance tests in a closed batch photoreactor show that these heterostructured powders exhibit limited water reduction efficiencies. To test whether Fermi level pinning intrinsically limits the water reduction capacity of CuFeO2, the Fermi level tunability in CuFeO2 is evaluated by creating CuFeO2/ITO and CuFeO2/H2O interfaces and analyzing the electronic and chemical properties of the interfaces through photoelectron spectroscopy. The results indicate that Fermi level pinning at the Fe3+/Fe2+ electron polaron formation level may intrinsically prohibit CuFeO2 from acquiring enough photovoltage to reach the water reduction potential. This result is complemented with density functional theory calculations as well. © 2020 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
- ItemSchlussbericht zum Antrag des LIKAT auf Gewährung einer Zuwendung zur Erweiterung der EPR- Spektrometertechnik für den Wissenschaftscluster „Light2Hydrogen“ im Rahmen des BMBF-Programms „Spitzenforschung und Innovation in den Neuen Ländern“(Hannover : Technische Informationsbibliothek (TIB), 2013) Brückner, Angelika[no abstract available]
- ItemVerbundvorhaben NAWAROs: Energetisch-stoffliche Verwertung von Kulturpflanzen - Ligninabtrennung, Fermentation und partielle Oxidation, Teilvorhaben: Oxidation von Methan und Methan/Kohlendioxid-Gemischen zu Oxygenaten : Abschlussbericht ; Laufzeit des Vorhabens: 01.06.2010 - 31.05.2013 (kostenneutrale Verlängerung bis 31.12.2013)(Hannover : Technische Informationsbibliothek (TIB), 2014) Martin, Andreas; Wohlrab, Sebastian[no abstract available]
- ItemPalladium-catalyzed synthesis of aldehydes from aryl iodides and formic acid with propylphosphonic anhydride as the activator(London : Nature Publishing Group, 2018) Wu, Xiao-FengAn interesting palladium-catalyzed carbonylative procedure for the synthesis of aromatic aldehydes from aryl iodides has been developed. By using propylphosphonic anhydride as the activator for formic acid, moderate to good yields of the corresponding aldehydes were produced with formic acid as the carbonyl and hydrogen donors. Interestingly, neither additional phosphine ligand nor inert gas protection is needed here.
- ItemSynthesegasproduktion durch katalytische Partialoxidation von Methan in Membranreaktoren (SynMem) : Abschlussbericht(Hannover : Technische Informationsbibliothek (TIB), 2010) Al Daroukh, Mahmoud; Noack, M.; Kölsch, P.; Wohlrab, S.; Dittmar, A.[no abstract available]
- ItemHochtemperatur-PEM-Brennstoffzellen mit Methanolreformer für portable Anwendungen - Micro-Power : Abschlussbericht ; Teilprojekt: Katalysatoren für die Methanolreformierung(Hannover : Technische Informationsbibliothek (TIB), 2010) Jähnisch, Klaus; Ehrich, Heike[no abstract available]
- ItemAbschlussbericht zum Verbundvorhaben "Neuartige Polymere auf Basis von Triglyceriden" : Darstellung der erzielten Ergebnisse für die Teilvorhaben mit den Partnern ; Teilvorhaben 1: Entwicklung von Katalysatoren und Herstellung neuer Monomere, Leibniz-Institut für Katalyse e.V. an der Universität Rostock (LITKAT) ; Teilvorhaben 2: Herstellung der Polyamide und Polyurethane, Fraunhofer-Institut für Chemische Technologie (ICT) ; Teilvorhaben 3: Entwicklung von Verfahren zur Herstellung von Monomeren für Kunststoffe aus plfanzlichen Ölsäuren, Evonik Oxeno GmbH (Oxeno) ; Teilvorhaben 4: Herstellung der Polyamide sowie Bewertung, Evonik Degussa GmbH (High Performance Polymers [HPP]) ; Teilvorhaben 5: Herstellung der Polyurethane sowie Bewertung und Dokumentation, Rampf Ecosystems GmbH & Co KG ; Laufzeit des Vorhabens/Berichtszeitraum: 01.10.2008 bis 31.12.2011(Hannover : Technische Informationsbibliothek (TIB), 2012) Kugler, Michael; Baumann, Franz-Erich; Fehrenbacher, Ulrich; Fridag, Dirk; Köckritz, Angela; Petrat, Frank-Martin; Tübke, Beatrice; Walter, Guido[no abstract available]
- ItemHigh-resolution imaging with SEM/T-SEM, EDX and SAM as a combined methodical approach for morphological and elemental analyses of single engineered nanoparticles(London [u.a.] : Royal Society of Chemistry, 2014) Rades, S.; Hodoroaba, V.-D.; Salge, T.; Wirth, T.; Lobera, M.P.; Labrador, R.H.; Natte, K.; Behnke, T.; Gross, T.; Unger, W.E.S.The combination of complementary characterization techniques such as SEM (Scanning Electron Microscopy), T-SEM (Scanning Electron Microscopy in Transmission Mode), EDX (Energy Dispersive X-ray Spectroscopy) and SAM (Scanning Auger Microscopy) has been proven to be a powerful and relatively quick characterization strategy for comprehensive morphological and chemical characterization of individual silica and titania nanoparticles. The selected "real life" test materials, silica and titania, are listed in the OECD guidance manual as representative examples because they are often used as commercial nanomaterials. Imaging by high resolution SEM and in the transmission mode by T-SEM allows almost simultaneous surface and in-depth inspection of the same particle using the same instrument. EDX and SAM enable the chemical characterization of bulk and surface of individual nanoparticles. The core-shell properties of silica based materials are addressed as well. Titania nominally coated by silane purchased from an industrial source has been found to be inhomogeneous in terms of chemical composition.