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  • 1. Baburin, Igor A
    et al.
    Klechikov, Alexey
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Mercier, Guillaume
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Talyzin, Alexandr
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Seifert, Gotthard
    Hydrogen adsorption by perforated graphene2015In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 40, no 20, 6594-6599 p.Article in journal (Refereed)
    Abstract [en]

    We performed a combined theoretical and experimental study of hydrogen adsorption in graphene systems with defect-induced additional porosity. It is demonstrated that perforation of graphene sheets results in increase of theoretically possible surface areas beyond the limits of ideal defect-free graphene (∼2700 m2/g) with the values approaching ∼5000 m2/g. This in turn implies promising hydrogen storage capacities up to 6.5 wt% at 77 K, estimated from classical Grand canonical Monte Carlo simulations. Hydrogen sorption was studied for the samples of defected graphene with surface area of ∼2900 m2/g prepared using exfoliation of graphite oxide followed by KOH activation. The BET surface area of studied samples thus exceeded the value of single-layered graphene. Hydrogen uptake measured at 77 K and 296 K amounts to 5.5 wt% (30 bar) and to 0.89 wt% (120 bar), respectively. 

  • 2.
    Hultman, Martin
    et al.
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies.
    Yaras, Ali
    Model Energy, Cemil Topuzlu Str. Is Bankasi Blocks, F Block 12/24, Fenerbahce, Kadikoy, Istanbul, Turkey.
    The socio-technological history of hydrogen and fuel cells in Sweden1978-2005: mapping the innovation trajectory2012In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 37, no 17, 12043-12053 p.Article in journal (Refereed)
    Abstract [en]

    At the turn of the millennium high expectations were connected to fuel cells. Various energy companies, politicians as well as many initiated public–private partnerships were of the same opinion: a Hydrogen Economy would combine economic growth with environmental concerns and security of energy supply and that was crucial for the future. But this was not the first time there were high expectations on fuel cells and in this article we map the changes 1978–2005 from energy transformers over to batteries and then end up as energy sources. We take their heterogeneous character for genuine and analyse how they are part of different discourses by following the construction of them by actor-networks. The article discuss how fuel cells and hydrogen had to change to fit together with the discourse of ecomodernisation, or to put the question differently, we analyse which aspects of the heterogeneous fuel cell technology are emphasised when connected to the iscourse of ecomodernisation. This analysis and the conclusions drawn contribute to a better understanding of technological change and also show important lessons for practitioners

  • 3.
    Luzan, Serhiy
    et al.
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Jung, Heejin
    Department of Applied Chemistry, College of Science and Technology, Hanyang University, Republic of Korea.
    Chun, Hyungphil
    Department of Applied Chemistry, College of Science and Technology, Hanyang University, Republic of Korea.
    Talyzin, Alexandr
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Hydrogen storage in Co-and Zn-based metal-organic frameworks at ambient temperature2009In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 34, no 24, 9754-9759 p.Article in journal (Refereed)
    Abstract [en]

    Hydrogen adsorption properties of some Co-and Zn-based Metal-Organic Framework (MOF) materials were studied at near ambient temperatures. Maximal hydrogen storage capacity of 0.75 wt% was found for a Zn-based material at 175 Bar hydrogen pressure and T = -4 degrees C. Hydrogen adsorption correlated linearly with BET surface area and strongly depends on temperature. Relatively low structural stability of some MOF's results in framework collapse during degassing and hydrogen adsorption measurements.

  • 4. Malolepszy, A
    et al.
    Mazurkiewicz, M
    Stobinski, L
    Lesiak, B
    Kövér, L
    Tóth, J
    Mierzwa, B
    Borodzinski, A
    Nitze, Florian
    Umeå University, Faculty of Science and Technology, Department of Physics. Chalmers University of Technology, Department of Chemical and Biological Engineering – Division of Applied Surface Chemistry, Göteborg, Sweden.
    Wågberg, Thomas
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Deactivation resistant Pd-ZrO2 supported on multiwall carbon nanotubes catalyst for direct formic acid fuel cells2015In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 40, no 46, 16724-16733 p.Article in journal (Refereed)
    Abstract [en]

    One of the main problems of palladium based catalysts for a direct formic acid fuel cell (DFAFC) is their low stability during a long-term operation. In these studies, the Pd–ZrO2 catalyst supported on the multiwall carbon nanotubes (MWCNTs) was prepared and thermo-chemically treated. These catalysts were tested in a fuel cell for formic acid electrooxidation, and their chemical composition and structure were characterised by the XPS, STEM, HR-TEM and XRD techniques.

    It was found that the Pd–ZrO2/MWCNTs catalyst after synthesis causes oscillations of the cell voltage during operation resulting in significantly higher deactivation resistance than that of Pd/MWCNTs. This may be attributed to the “self-cleaning” mechanism of poisoned Pd catalyst by carbon monoxide through the electrochemical oxidation of COads (adsorbed) to CO2 (gas).

  • 5.
    Mohapatra, Anasuya
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Leul, Melakeselam
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Sandström, Gunnar
    Karolinska Institutet, Department of Laboratory Medicine, Division of Clinical Bacteriology, Karelinska University Hospital, Huddinge, Stockholm, Sweden.
    Sellstedt, Anita
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Occurrence and characterisation of the hydrogen-evolving enzyme in Frankia sp.2006In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 31, no 11, 1445-1451 p.Article in journal (Refereed)
    Abstract [en]

    An increase in hydrogen evolution from the hydrogen-evolving enzyme in the actinomycete Frankia was recorded in the presence of nickel. Immunogold localisation analysis of the intracellular distribution of hydrogenase proteins indicated that they were evenly distributed in the membranes and cytosol of both hyphae and vesicles. In addition, molecular characterisation of the hydrogen-evolving enzyme at the proteomic level, using two-dimensional gel electrophoresis combined with mass spectrometry, confirmed that the Frankia hydrogen-evolving enzyme is similar to the cyanobacterial bidirectional hydrogenase of Anabena siamensis.

  • 6. Ng, Chun Hin
    et al.
    Winther-Jensen, Orawan
    Kolodziejczyk, Bartlomiej
    Ohlin, C. Andre
    Winther-Jensen, Bjorn
    Photo-electrocatalytic H-2 evolution on poly(2,2 ‘-bithiophene) at neutral pH2014In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 39, no 32, 18230-18234 p.Article in journal (Refereed)
    Abstract [en]

    Vapour phase polymerised (VPP) polybithiophene (PBTh) on glassy carbon is revealed to be an efficient photo-electrocatalytic electrode for the hydrogen evolution reaction (HER). An onset potential of -0.03 V vs SCE for the HER is observed on illumination using visible light in 0.1 mol L-1 phosphate buffer at pH 6.9, 600 mV lower in energy than E-o. Hydrogen evolution is confirmed using gas chromatography with a calculated faradaic efficiency of 34% when holding at a potential of -0.5 V. Importantly, this process occurs without platinum and under neutral aqueous conditions thus revealing a significant but overlooked application for PBTh: a potential low-cost cathode material for the splitting of water. 

  • 7.
    Sharifi, Tiva
    et al.
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Kwong, Wai Ling
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Berends, Hans-Martin
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Larsen, Christian
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Messinger, Johannes
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Wågberg, Thomas
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Maghemite nanorods anchored on a 3D nitrogen-doped carbon nanotubes substrate as scalable direct electrode for water oxidation2016In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 41, no 1, 69-78 p.Article in journal (Refereed)
    Abstract [en]

    A hybrid catalyst 3D electrode for electrochemical water oxidation to molecular oxygen is presented. The electrode comprises needle shaped maghemite nanorods firmly anchored to nitrogen doped carbon nanotubes, which in turn are grown on a conducting carbon paper that acts as efficient current collector. In 0.1 M KOH this hybrid electrode reaches a current density of 1 mA/cm(2) (geometric surface) at an overpotential of 362 mV performing high chronoamperometric stability. The electrochemical attributes point toward efficient catalytic processes at the surface of the maghemite nanorods, and demonstrate a very high surface area of the 3D electrode, as well as a firm anchoring of each active component enabling an efficient charge transport from the surface of the maghemite rods to the carbon paper current collector. The latter property also explains the good stability of our hybrid electrode compared to transition metal oxides deposited on conducting support such as fluorine doped tin oxide. These results introduce maghemite as efficient, stable and earth abundant oxygen evolution reaction catalyst, and provide insight into key issues for obtaining practical electrodes for oxygen evolution reaction, which are compatible with large scale production processes. 

  • 8. Tokarev, A V
    et al.
    Kirilin, A V
    Murzina, E V
    Eränen, K
    Kustov, L M
    D Yu, Murzin
    Mikkola, Jyri-Pekka
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    The role of bio-ethanol in aqueous phase reforming to sustainable hydrogen2010In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 35, no 22, 12642-9 p.Article in journal (Refereed)
    Abstract [en]

    Aqueous Phase Reforming (APR) has during the recent years emerged as a potent, alternative means of processing raw materials of biological origin to component suitable as chemicals and fuel components. In contrary to e.g. steam reforming, aqueous phase reforming bares the promise of lower temperatures in processing which gives rise to potential of reduced energy consumption in the upgrading process itself.Aqueous phase reforming was studied over Pt/Al2O3 at 225 °C. Stable catalyst performance and high selectivity was observed. Upon a comparison of two ‘bio-alcohols’, bio-ethanol and Sorbitol (a sugar alcohol), the latter one is a better feedstock from overall energy utilization viewpoint but the use of it results in a broad range of products. Interestingly, in the case of sorbitol–ethanol mixtures, an improvement in the hydrogen yield was observed.

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