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  1. Article ; Online: Electrochemical CO

    Gawel, Alina / Jaster, Theresa / Siegmund, Daniel / Holzmann, Johannes / Lohmann, Heiko / Klemm, Elias / Apfel, Ulf-Peter

    iScience

    2022  Volume 25, Issue 4, Page(s) 104011

    Abstract: For the efficient electrochemical conversion of ... ...

    Abstract For the efficient electrochemical conversion of CO
    Language English
    Publishing date 2022-03-04
    Publishing country United States
    Document type Journal Article ; Review
    ISSN 2589-0042
    ISSN (online) 2589-0042
    DOI 10.1016/j.isci.2022.104011
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Influence of the ZnCrAl Oxide Composition on the Formation of Hydrocarbons from Syngas.

    Kull, Tobias / Wiesmann, Thomas / Wilmsen, Andrea / Purcel, Maximilian / Muhler, Martin / Lohmann, Heiko / Zeidler-Fandrich, Barbara / Apfel, Ulf-Peter

    ACS omega

    2022  Volume 7, Issue 47, Page(s) 42994–43005

    Abstract: The conversion of syngas into value-added hydrocarbons gains increasing attention due to its potential to produce sustainable platform chemicals from simple starting materials. Along this line, the "OX-ZEO" process that combines a methanol synthesis ... ...

    Abstract The conversion of syngas into value-added hydrocarbons gains increasing attention due to its potential to produce sustainable platform chemicals from simple starting materials. Along this line, the "OX-ZEO" process that combines a methanol synthesis catalyst with a zeolite, capable of catalyzing the methanol-to-hydrocarbon reaction, was found to be a suitable alternative to the classical Fischer-Tropsch synthesis. Hitherto, understanding the mechanism of the OX-ZEO process and simultaneously optimizing the CO conversion and the selectivity toward a specific hydrocarbon remains challenging. Herein, we present a comparison of a variety of ZnCrAl oxides with different metal ratios combined with a H-ZSM-5 zeolite for the conversion of syngas to hydrocarbons. The effect of aluminum on the catalytic activity was investigated for ZnCrAl oxides with a Zn/Cr ratio of 4:1, 1:1, and 1:2. The product distribution and CO conversion were found to be strongly influenced by the Zn/Cr/Al ratio. Although a ratio of Zn/Cr of 1:2 was best to produce lower olefins and aromatics, with aromatic selectivities of up to 37%, catalysts with a 4:1 ratio revealed high paraffin selectivity up to 52%. Notably, a distinct effect of aluminum in the oxide lattice on the catalytic activity and product selectivity was observed, as a higher Al content leads to a lower CO conversion and a changed product spectrum. We provide additional understanding of the influence of different compositions of ZnCrAl oxides on their surface properties and the catalytic activity in the OX-ZEO process. Furthermore, the variation of the zeolite component supports the important role of the channel topology of the porous support material for the hydrocarbon production. In addition, variation of the gas hourly space velocity showed a correlation of contact time, CO conversion, and hydrocarbon selectivity. At a gas hourly space velocity of 4200 mL/g
    Language English
    Publishing date 2022-11-16
    Publishing country United States
    Document type Journal Article
    ISSN 2470-1343
    ISSN (online) 2470-1343
    DOI 10.1021/acsomega.2c05225
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Electrochemical CO

    Jaster, Theresa / Gawel, Alina / Siegmund, Daniel / Holzmann, Johannes / Lohmann, Heiko / Klemm, Elias / Apfel, Ulf-Peter

    iScience

    2022  Volume 25, Issue 4, Page(s) 104010

    Abstract: Tackling climate change is one of the undoubtedly most important challenges at the present time. This review deals mainly with the chemical aspects of the current status for converting the greenhouse gas ... ...

    Abstract Tackling climate change is one of the undoubtedly most important challenges at the present time. This review deals mainly with the chemical aspects of the current status for converting the greenhouse gas CO
    Language English
    Publishing date 2022-03-03
    Publishing country United States
    Document type Journal Article ; Review
    ISSN 2589-0042
    ISSN (online) 2589-0042
    DOI 10.1016/j.isci.2022.104010
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    Kategorien

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  4. Article ; Online: Enhancement of CO2RR product formation on Cu-ZnO-based electrodes by varying ink formulation and post treatment methods

    Jaster, Theresa / Albers, Simon / Leonhard, Armin / Kräenbring, Mena-Alexander / Lohmann, Heiko / Zeidler-Fandrich, Barbara / Özcan, Fatih / Segets, Doris / Apfel, Ulf-Peter

    2023  

    Abstract: Numerous catalysts have been reported with enhanced performance, e.g. longer lifetime and improved selectivity, for the electrochemical CO2 reduction reaction (CO2RR). Respectively little is, however, known about the influence of the electrode ... ...

    Abstract Numerous catalysts have been reported with enhanced performance, e.g. longer lifetime and improved selectivity, for the electrochemical CO2 reduction reaction (CO2RR). Respectively little is, however, known about the influence of the electrode structuring and pre-treatment on this reaction for catalytic layers. Thus, we herein report on the modification of the catalyst environment of a Cu-ZnO-carbon black catalyst by variation of the ink composition and subsequent electrode treatment before performing CO2RR. We furthermore provide insight into the impact of solvents used for the ink preparation, ionomer and additives like pore forming agents as well as post treatment steps in terms of pressing and sintering of electrodes on the CO2RR performance. Although using the same catalyst for all electrodes, remarkable differences in hydrophobicity, surface morphology and electrochemical performance with respect to stability and product distribution are observed. Our study reveals the critical role of the catalytic layer assembly aside using proper catalysts. We furthermore show that the parasitic hydrogen formation and flooding behavior can be lowered and C2+ product formation enhanced when operated in optimized gas diffusion electrodes (GDE).

    Online First
    Subject code 660
    Language English
    Publishing country de
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  5. Article ; Online: Application of Design of Experiments for Catalytic Oxygen Removal over Pt/γ-Al2O3 Catalyst

    Suh, Sung Youn / Geitner, Christian / Hänel, Marvin / Wiesmann, Thomas / Watermann, Clara / Lohmann, Heiko / Apfel, Ulf-Peter / Zeidler-Fandrich, Barbara

    2022  

    Abstract: 1509 ... 1515 ... The following orientational study uses a factorial experimental design (DoE) strategy to determine the influence of different process parameters on the catalytic removal of oxygen traces (4500-9000 ppmv O2) from coke oven gas by commercial ... ...

    Abstract 1509

    1515

    The following orientational study uses a factorial experimental design (DoE) strategy to determine the influence of different process parameters on the catalytic removal of oxygen traces (4500-9000 ppmv O2) from coke oven gas by commercial Pt/γ-Al2O3. Along this line, various experiments have been performed from 1 up to 11 bar and 150-250 °C with a gas hourly space velocity between 20 000 and 25 000 h-1. The statistical analysis demonstrates that the applied temperature and pressure have a significant impact on the oxygen removal process. Experiments using gas mixtures with additional 350 ppmv H2S indicate a deactivation of the catalyst with a 66 % oxygen conversion at 250 °C and 6 bar. The close agreement between predicted and experimental data highlights the efficient approach for optimizing the oxygen removal from coke oven gas utilizing DoE strategies.

    94

    10
    Keywords Carbon2Chem ; Catalytic oxygen removal ; Coke oven gas ; Design of experiments ; Pt/g-Al2O3
    Subject code 660
    Language English
    Publishing country de
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    Full text online

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    Inter-library loan at ZB MED

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  6. Article ; Online: Influence of the ZnCrAl Oxide Composition on the Formation of Hydrocarbons from Syngas

    Kull, Tobias / Wiesmann, Thomas / Wilmsen, Andrea Paula / Purcel, Maximilian / Muhler, Martin / Lohmann, Heiko / Zeidler-Fandrich, Barbara / Apfel, Ulf-Peter

    2022  

    Abstract: 42994 ... 43005 ... The conversion of syngas into value-added hydrocarbons gains increasing attention due to its potential to produce sustainable platform chemicals from simple starting materials. Along this line, the "OX-ZEO" process that combines a ... ...

    Abstract 42994

    43005

    The conversion of syngas into value-added hydrocarbons gains increasing attention due to its potential to produce sustainable platform chemicals from simple starting materials. Along this line, the "OX-ZEO" process that combines a methanol synthesis catalyst with a zeolite, capable of catalyzing the methanol-to-hydrocarbon reaction, was found to be a suitable alternative to the classical Fischer-Tropsch synthesis. Hitherto, understanding the mechanism of the OX-ZEO process and simultaneously optimizing the CO conversion and the selectivity toward a specific hydrocarbon remains challenging. Herein, we present a comparison of a variety of ZnCrAl oxides with different metal ratios combined with a H-ZSM-5 zeolite for the conversion of syngas to hydrocarbons. The effect of aluminum on the catalytic activity was investigated for ZnCrAl oxides with a Zn/Cr ratio of 4:1, 1:1, and 1:2. The product distribution and CO conversion were found to be strongly influenced by the Zn/Cr/Al ratio. Although a ratio of Zn/Cr of 1:2 was best to produce lower olefins and aromatics, with aromatic selectivities of up to 37%, catalysts with a 4:1 ratio revealed high paraffin selectivity up to 52%. Notably, a distinct effect of aluminum in the oxide lattice on the catalytic activity and product selectivity was observed, as a higher Al content leads to a lower CO conversion and a changed product spectrum. We provide additional understanding of the influence of different compositions of ZnCrAl oxides on their surface properties and the catalytic activity in the OX-ZEO process. Furthermore, the variation of the zeolite component supports the important role of the channel topology of the porous support material for the hydrocarbon production. In addition, variation of the gas hourly space velocity showed a correlation of contact time, CO conversion, and hydrocarbon selectivity. At a gas hourly space velocity of 4200 mL/gcat h, CO conversion as high as 44% along with a CO2 selectivity of 42% and a lower paraffin (C2 0-C4 0) ...
    Keywords Syngas ; Hydrocarbon
    Subject code 660
    Language English
    Publishing country de
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  7. Book ; Online: Electrochemical CO2 Reduction - The Macroscopic World of Electrode Design, Reactor Concepts & Economic Aspects

    Gawel, Alina / Jaster, Theresa / Siegmund, Daniel / Holzmann, Johannes / Lohmann, Heiko / Klemm, Elias / Apfel, Ulf-Peter

    2022  

    Abstract: Art. 104011, 36 S. ... For the efficient electrochemical conversion of CO2 into valuable chemical feedstocks, a well-coordinated interaction of all electrolyzer compartments is required. In addition to the catalyst, whose role is described in detail in the ...

    Abstract Art. 104011, 36 S.

    For the efficient electrochemical conversion of CO2 into valuable chemical feedstocks, a well-coordinated interaction of all electrolyzer compartments is required. In addition to the catalyst, whose role is described in detail in the part ""Electrochemical CO2 Reduction towards Multicarbon Alcohols - The Microscopic World of Catalysts & Process Conditions"" of this divided review, the general cell setups, design, and manufacture of the electrodes, membranes used, and process parameters must be optimally matched. The authors' goal is to provide a comprehensive review of the current literature on how these aspects affect the overall performance of CO2 electrolysis. To be economically competitive as an overall process, the framework conditions, i.e., CO2 supply and reaction product treatment, must also be considered. If the key indicators for current density, selectivity, cell voltage, and lifetime of a CO2 electrolyzer mentioned in the techno-economic consideration of this review are met, electrochemical CO2 reduction can make a valuable contribution to the creation of closed carbon cycles and to a sustainable energy economy.

    25

    Nr.4
    Keywords membrane ; CO2 reduction ; process
    Subject code 660
    Language English
    Publishing country de
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  8. Book: The German path to natural gas liberalisation

    Lohmann, Heiko

    is it a special case?

    (Oxford Institute for Energy Studies : NG ; 14)

    2006  

    Institution Oxford Institute for Energy Studies
    Author's details Heiko Lohmann
    Series title Oxford Institute for Energy Studies : NG ; 14
    Keywords Marktentwicklung ; Erdgasmarkt ; Marktstruktur ; Deregulierung ; Liberalisierung ; Wettbewerb ; Erdgaspolitik ; Deutschland
    Language English
    Size XV, 183 S., Ill., graph. Darst., 22cm
    Document type Book
    Note Includes bibliographical references
    ISBN 1901795470 ; 9781901795479
    Database ECONomics Information System

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  9. Conference proceedings ; Online: Comparative tests of catalysts for reforming of tars and methane in biomass-derived synthesis gas from fuidized bed gasification ; Comparative tests of catalysts for tar reforming

    Hamel, Chrisitan / Lohmann, Heiko / Schulzke, Tim / Unger, Christoph

    2012  

    Abstract: Several different commercially-available and recently-developed catalysts were tested for the reforming of model tar compounds and methane in a simulated producer gas from allothermal biomass gasification in a laboratory scale test rig at Fraunhofer ... ...

    Abstract Several different commercially-available and recently-developed catalysts were tested for the reforming of model tar compounds and methane in a simulated producer gas from allothermal biomass gasification in a laboratory scale test rig at Fraunhofer UMSICHT. Monolith and bulk catalysts were compared with respect to their conversion performance in a synthetic syngas in a first project step without typical poisoning substances like e.g. sulfur. Precious-metal catalysts were able to almost completely remove aromatic compounds even at 800 °C and very short residence times over 5 hours of test time. If similar conversion rates can be reached for the upcoming tests in the presence of sulfur as well, the catalysts would be applicable for allothermal gasification systems. The best of the nickel ca talysts also showed high conversion levels for both methane and aromatics, but could not totally convert all tar components. One catalyst doped with a promoting compound specifically converted the tar components without showing high activity towards methane. Some first results of the influence of added H2S as the major sulfur component in the gas are also reported here as part of detailed investigations for the most promising catalysts.
    Keywords tar ; catalyst ; gasification ; fluidised bed gasification ; 620
    Subject code 660
    Language English
    Publishing country de
    Document type Conference proceedings ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    Full text online

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  10. Conference proceedings ; Online: Comparative tests of catalysts for reforming of tars and methane in biomass-derived synthesis gas from fuidized bed gasification

    Hamel, Chrisitan / Lohmann, Heiko / Schulzke, Tim / Unger, Christoph

    Fraunhofer UMSICHT Oh

    Presentation held at 20th European Biomass Conference, Milan, Italy, June 18th-22nd, 2012

    2012  

    Abstract: Several different commercially-available and recently-developed catalysts were tested for the reforming of model tar compounds and methane in a simulated producer gas from allothermal biomass gasification in a laboratory scale test rig at Fraunhofer ... ...

    Abstract Several different commercially-available and recently-developed catalysts were tested for the reforming of model tar compounds and methane in a simulated producer gas from allothermal biomass gasification in a laboratory scale test rig at Fraunhofer UMSICHT. Monolith and bulk catalysts were compared with respect to their conversion performance in a synthetic syngas in a first project step without typical poisoning substances like e.g. sulfur. Precious-metal catalysts were able to almost completely remove aromatic compounds even at 800 °C and very short residence times over 5 hours of test time. If similar conversion rates can be reached for the upcoming tests in the presence of sulfur as well, the catalysts would be applicable for allothermal gasification systems. The best of the nickel ca talysts also showed high conversion levels for both methane and aromatics, but could not totally convert all tar components. One catalyst doped with a promoting compound specifically converted the tar components without showing high activity towards methane. Some first results of the influence of added H2S as the major sulfur component in the gas are also reported here as part of detailed investigations for the most promising catalysts.
    Keywords tar ; catalyst ; gasification ; fluidised bed gasification
    Subject code 660
    Language English
    Publishing country de
    Document type Conference proceedings ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    Full text online

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    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.

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