LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Back to previous search Search history
Advanced search

Your last searches

  1. AU="Steiger Patrick"
  2. AU="Dashti, Kobra"
  3. AU="Henrik Szőke"

Search results

Result 1 - 8 of total 8

Search options

  1. Article ; Online: Fluorescence-detected quick-scanning X-ray absorption spectroscopy.

    Clark, Adam H / Steiger, Patrick / Bornmann, Benjamin / Hitz, Stephan / Frahm, Ronald / Ferri, Davide / Nachtegaal, Maarten

    Journal of synchrotron radiation

    2020  Volume 27, Issue Pt 3, Page(s) 681–688

    Abstract: Time-resolved X-ray absorption spectroscopy (XAS) offers the possibility to monitor the state of materials during chemical reactions. While this technique has been established for transmission measurements for a number of years, XAS measurements in ... ...

    Abstract Time-resolved X-ray absorption spectroscopy (XAS) offers the possibility to monitor the state of materials during chemical reactions. While this technique has been established for transmission measurements for a number of years, XAS measurements in fluorescence mode are challenging because of limitations in signal collection as well as detectors. Nevertheless, measurements in fluorescence mode are often the only option to study complex materials containing heavy matrices or in samples where the element of interest is in low concentration. Here, it has been demonstrated that high-quality quick-scanning full extended X-ray absorption fine-structure data can be readily obtained with sub-second time resolution in fluorescence mode, even for highly diluted samples. It has also been demonstrated that in challenging samples, where transmission measurements are not feasible, quick fluorescence can yield significant insight in reaction kinetics. By studying the fast high-temperature oxidation of a reduced LaFe
    Language English
    Publishing date 2020-04-06
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2021413-3
    ISSN 1600-5775 ; 0909-0495
    ISSN (online) 1600-5775
    ISSN 0909-0495
    DOI 10.1107/S1600577520002350
    Database MEDical Literature Analysis and Retrieval System OnLINE

    Full text online

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  2. Article: Smart material concept: reversible microstructural self-regeneration for catalytic applications

    Burnat, Dariusz / Kontic, Roman / Holzer, Lorenz / Steiger, Patrick / Ferri, Davide / Heel, Andre

    Journal of materials chemistry A. 2016 July 26, v. 4, no. 30

    2016  

    Abstract: This paper presents a proof-of-concept study and demonstrates the next generation of a “smart” catalyst material, applicable to high temperature catalysis and electro-catalysis such as gas processing and as a catalyst for solid oxide cells. A modified ... ...

    Abstract This paper presents a proof-of-concept study and demonstrates the next generation of a “smart” catalyst material, applicable to high temperature catalysis and electro-catalysis such as gas processing and as a catalyst for solid oxide cells. A modified citrate-gel technique was developed for the synthesis of LaxSr1−1.5xTi1−yNiyO3−δ. This method allowed the synthesis of single phase materials with a high specific surface area, after the first calcination step at temperatures as low as 650 °C. Up to 5 at% of nickel could be incorporated into the perovskite structure at this low calcination temperature. X-ray powder diffraction and microscopy techniques have proven the exsolution of nickel nanoclusters under low oxygen partial pressure. The amount of exsoluted nickel nanoparticles was sensitive to surface finishing, whereby much more exsoluted nanoparticles were observed on pre-treated and polished surfaces as compared to original ones. Increasing A-site deficiency leads to a larger number of nickel particles on the surface, indicating a destabilizing influence of the A-site vacancies on the B-site metal cations. Repetitive redox cycles prove that the nickel exsolution and re-integration is a fully reversible process. These materials working in a cyclic and repetitive way may overcome the drawbacks of currently used conventional catalysts used for high temperature systems and overcome major degradation issues related to catalyst poisoning and coarsening-induced aging.
    Keywords X-ray diffraction ; catalysts ; catalytic activity ; metal ions ; microscopy ; nanoparticles ; nickel ; oxygen ; surface area ; temperature
    Language English
    Dates of publication 2016-0726
    Size p. 11939-11948.
    Publishing place The Royal Society of Chemistry
    Document type Article
    ZDB-ID 2702232-8
    ISSN 2050-7496 ; 2050-7488
    ISSN (online) 2050-7496
    ISSN 2050-7488
    DOI 10.1039/c6ta03417a
    Database NAL-Catalogue (AGRICOLA)

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  3. Article: Low-Temperature CO Oxidation over Combustion Made Fe- and Cr-Doped Co3O4 Catalysts: Role of Dopant’s Nature toward Achieving Superior Catalytic Activity and Stability

    Baidya, Tinku / Bera Parthasarathi / Biswas Krishanu / Haruta Masatake / Katiyar Nirmal Kumar / Murayama Toru / Safonova Olga V / Steiger Patrick

    The Journal of Physical Chemistry C. 2017 July 20, v. 121, no. 28

    2017  

    Abstract: Co3O4 with a spinel structure shows unique activity for CO oxidation at low temperature under dry conditions; however the active surface is not very stable. In this study, two series of Fe- and Cr-doped Co3O4 catalysts were prepared by a single-step ... ...

    Abstract Co3O4 with a spinel structure shows unique activity for CO oxidation at low temperature under dry conditions; however the active surface is not very stable. In this study, two series of Fe- and Cr-doped Co3O4 catalysts were prepared by a single-step solution combustion technique. Fe was chosen because of its redox activity corresponding to the Fe2+/Fe3+ redox couple and compared to Cr, which is mainly stable in the Cr3+ state. The catalytic activity of new materials for low-temperature CO oxidation was correlated to the nature of the dopant. As a function of dopant concentration, the temperature corresponding to the 50% CO conversion (T50) demonstrated significant differences. The maximal activity was achieved for 15% Fe-doped Co3O4 with T50 of −85 °C and remained almost constant up to 25% Fe. In the case of Cr, the activity was observed to be maximum for 7% of Cr with T50 of −42 °C and significantly decreased for higher Cr loadings. Similarly, there was a contrasting behavior in catalyst stability too. 100% CO conversion was achieved below −60 °C for 15% Fe/Co3O4 catalyst and remained unchanged even after calcination at 600 °C. In contrast, Co3O4 or 15% Cr/Co3O4 catalysts strongly deactivated after the same treatment. These differences were correlated to the oxidation states, coordination numbers, the nature of surface planes, and the redox properties. We observed that both Cr and Fe were typically present in the +3 oxidation state, occupying octahedral sites in the spinel structure. The catalysts were mainly exposed to (111) and (220) planes on the surface. H2-TPR indicated clear differences in the redox activity of materials due to Fe and Cr substitutions. The reducibility of surface Co3+ species remained similar in all Fe-doped Co3O4 catalysts in contrast to nonreducible Cr-doped analogs, which shifted the reduction temperature to the higher values. As the Fe3+/Fe2+ redox couple partly substituted the Co3+/Co2+ redox couple in the spinel structure, similar bond strength of Fe–O keep redox activity of Co3+ species almost unchanged leading to higher activity and stability of Fe/Co3O4 catalysts for low-temperature CO oxidation. In contrast, nonreducible Cr3+ species characterized by strong Cr–O bond substituting active Co3+ sites can make the Cr/Co3O4 surface less active for CO oxidation.
    Keywords carbon monoxide ; catalysts ; catalytic activity ; chemical bonding ; chromium ; cobalt oxide ; combustion ; iron ; temperature
    Language English
    Dates of publication 2017-0720
    Size p. 15256-15265.
    Publishing place American Chemical Society
    Document type Article
    ISSN 1932-7455
    DOI 10.1021%2Facs.jpcc.7b04348
    Database NAL-Catalogue (AGRICOLA)

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  4. Book ; Thesis: Computer-based support for comprehensive personal risk management

    Steiger, Patrick

    (IVW-Schriftenreihe ; 38)

    2000  

    Author's details Patrick Steiger
    Series title IVW-Schriftenreihe ; 38
    Keywords Risikomanagement ; Individuum ; Computerunterstützung ; Privater Haushalt ; Theorie ; Soziale Beziehungen
    Language English
    Size XV, 219 S, Ill., graph. Darst, 23 cm
    Document type Book ; Thesis
    Thesis / German Habilitation thesis Zugl.: Zürich, Diss., Univ., 2000
    Accompanying material CD-ROM
    ISBN 3952149349 ; 9783952149348
    Database ECONomics Information System

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  5. Article ; Online: Structural Reversibility and Nickel Particle stability in Lanthanum Iron Nickel Perovskite-Type Catalysts.

    Steiger, Patrick / Delmelle, Renaud / Foppiano, Debora / Holzer, Lorenz / Heel, Andre / Nachtegaal, Maarten / Kröcher, Oliver / Ferri, Davide

    ChemSusChem

    2017  Volume 10, Issue 11, Page(s) 2505–2517

    Abstract: Perovskite-type oxides have shown the ability to reversibly segregate precious metals from their structure. This reversible segregation behavior was explored for a commonly used catalyst metal, Ni, to prevent Ni sintering, which is observed on most ... ...

    Abstract Perovskite-type oxides have shown the ability to reversibly segregate precious metals from their structure. This reversible segregation behavior was explored for a commonly used catalyst metal, Ni, to prevent Ni sintering, which is observed on most catalyst support materials. Temperature-programmed reduction, X-ray diffraction, X-ray absorption spectroscopy, electron microscopy, and catalytic activity tests were used to follow the extent of reversible Ni segregation. LaFe
    MeSH term(s) Calcium Compounds ; Catalysis ; Hydrogenation ; Iron/chemistry ; Lanthanum/chemistry ; Nickel/chemistry ; Oxidation-Reduction ; Oxides/chemistry ; Titanium
    Chemical Substances Calcium Compounds ; Oxides ; perovskite (12194-71-7) ; Lanthanum (6I3K30563S) ; Nickel (7OV03QG267) ; Titanium (D1JT611TNE) ; Iron (E1UOL152H7)
    Language English
    Publishing date 2017-06-09
    Publishing country Germany
    Document type Journal Article
    ISSN 1864-564X
    ISSN (online) 1864-564X
    DOI 10.1002/cssc.201700358
    Database MEDical Literature Analysis and Retrieval System OnLINE

    Full text online

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  6. Article ; Online: Degradation performance of biodegradable Fe-Mn-C(-Pd) alloys.

    Schinhammer, Michael / Steiger, Patrick / Moszner, Frank / Löffler, Jörg F / Uggowitzer, Peter J

    Materials science & engineering. C, Materials for biological applications

    2013  Volume 33, Issue 4, Page(s) 1882–1893

    Abstract: Biodegradable metals offer great potential in circumventing the long-term risks and side effects of medical implants. Austenitic Fe-Mn-C-Pd alloys feature a well-balanced combination of high strength and considerable ductility which make them attractive ... ...

    Abstract Biodegradable metals offer great potential in circumventing the long-term risks and side effects of medical implants. Austenitic Fe-Mn-C-Pd alloys feature a well-balanced combination of high strength and considerable ductility which make them attractive for use as degradable implant material. The focus of this study is the evaluation of the degradation performance of these alloys by means of immersion testing and electrochemical impedance spectroscopy in simulated body fluid. The Fe-Mn-C-Pd alloys are characterized by an increased degradation rate compared to pure Fe, as revealed by both techniques. Electrochemical measurements turned out to be a sensitive tool for investigating the degradation behavior. They not only show that the polarization resistance is a measure of corrosion tendency, but also provide information on the evolution of the degradation product layers. The mass loss data from immersion tests indicate a decreasing degradation rate for longer times due to the formation of degradation products on the sample surfaces. The results are discussed in detail in terms of the degradation mechanism of Fe-based alloys in physiological media.
    MeSH term(s) Alloys/chemistry ; Biocompatible Materials/chemistry ; Biodegradation, Environmental ; Body Fluids/chemistry ; Dielectric Spectroscopy ; Electrochemical Techniques ; Electrolytes/chemistry ; Hydrogen/analysis ; Materials Testing ; Microscopy, Electron, Scanning ; Sulfuric Acids/chemistry
    Chemical Substances Alloys ; Biocompatible Materials ; Electrolytes ; Sulfuric Acids ; Hydrogen (7YNJ3PO35Z) ; sulfuric acid (O40UQP6WCF)
    Language English
    Publishing date 2013-05-01
    Publishing country Netherlands
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2012160-X
    ISSN 1873-0191 ; 0928-4931
    ISSN (online) 1873-0191
    ISSN 0928-4931
    DOI 10.1016/j.msec.2012.10.013
    Database MEDical Literature Analysis and Retrieval System OnLINE

    Full text online

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  7. Article: Ultra-Low-Temperature CO Oxidation Activity of Octahedral Site Cobalt Species in Co3O4 Based Catalysts: Unravelling the Origin of the Unique Catalytic Property

    Baidya, Tinku / Bera, Parthasarathi / Biswas, Krishanu / Haruta, Masatake / Katiyar, Nirmal Kumar / Kundu, Samapti / Lin, Mingyue / Lingaiah, Nakka / Malviya, Kirtiman Deo / Murayama, Toru / Nellaiappan, Subramanian / Pradhan, Swapan Kumar / Priolkar, Kaustubh R / Safonova, Olga / Sharma, Sudhanshu / Srinivasa Rao, Bolla / Steiger, Patrick

    Journal of physical chemistry. 2019 July 18, v. 123, no. 32

    2019  

    Abstract: Co3O4 with spinel structure shows CO oxidation activity at very low temperature under dry conditions. This study aims at finding the origin of the unique catalytic activity of Co species in Co3O4 based oxides. Although, octahedral site Co3+ species have ... ...

    Abstract Co3O4 with spinel structure shows CO oxidation activity at very low temperature under dry conditions. This study aims at finding the origin of the unique catalytic activity of Co species in Co3O4 based oxides. Although, octahedral site Co3+ species have been reported to be active in Co3O4 based catalysts, there is no solid explanation as to why Co is so special as compared with other metals like Fe having similar redox states. In this study, mainly, three model spinel catalysts including MnCo2O4, MnFe2O4, and CoCr2O4 have been chosen. A detailed analysis of bulk and crystal surface structure, surface properties of the catalysts, and redox properties of the active metals has been performed to understand the unusual catalytic activity. Low-temperature CO oxidation activity decreases in the following order: MnCo2O4 ≫ MnFe2O4 > CoCr2O4. It indicates that the Co2+ species in a tetrahedral site (in CoCr2O4) remains inactive for low-temperature catalytic activity, while Co3+ in an octahedral site (in MnCo2O4) is active in Co3O4 based catalysts. This result is corroborated with CoFe2O4 which shows a higher activity than CoCr2O4, as it has partial occupation of the octahedral site. Fe, being a weak redox metal, does not show low-temperature activity, although crystallite facets of MnCo2O4 and MnFe2O4 catalysts are predominantly exposed in the (100) and (110) lattice planes, which contain quite similar concentrations of Co3+ and Fe3+ species in both. The intensity of the redox peak for CO oxidation involving a Co3+/Co2+ couple in MnCo2O4 indicates a highly favorable reaction, while a nonresponsive behavior of Co species is observed in CoCr2O4. As expected, MnFe2O4 is proven to be weak, giving a much lower intensity of electrochemical CO oxidation. Both CO- and H2-TPR indicate a much higher reducibility of Co species in MnCo2O4 as compared with Co species in CoCr2O4 or Fe in MnFe2O4.
    Keywords carbon monoxide ; catalysts ; catalytic activity ; cobalt ; cobalt oxide ; crystallites ; electrochemistry ; iron ; models ; oxidation ; physical chemistry ; temperature
    Language English
    Dates of publication 2019-0718
    Size p. 19557-19571.
    Publishing place American Chemical Society
    Document type Article
    ISSN 1932-7455
    DOI 10.1021/acs.jpcc.9b04136
    Database NAL-Catalogue (AGRICOLA)

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  8. Book: Making electronic commerce easier to use with novel user interfaces

    Abad-Peiro, José L / Steiger, Patrick

    (Computer science/mathematics ; Research Report / IBM Zurich Research Lab. : RZ ; 3035 = 93081)

    1998  

    Author's details José L. Abad-Peiro and Patrick Steiger
    Series title Computer science/mathematics
    Research Report / IBM Zurich Research Lab. : RZ ; 3035 = 93081
    Language English
    Size 8 S
    Publisher IBM
    Publishing place Rüschlikon
    Document type Book
    Database Former special subject collection: coastal and deep sea fishing

    More links

    Kategorien

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

To top