| 1. |
- Björklund, Anna, et al.
(författare)
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Hydrogen as a transportation fuel produced from thermal gasification of municipal solid waste: an examination of two integrated technologies
- 2001
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Ingår i: International journal of hydrogen energy. - 0360-3199 .- 1879-3487. ; 26:11, s. 1209-1221
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Tidskriftsartikel (refereegranskat)abstract
- Innovative technologies are required to offset increasing consumption and declining stocks of non-renewable resources. This study examines a possible enhancement of waste management and transportation by integrating two emerging technologies: municipal solid waste (MSW) gasification and fuel cell vehicles (FCVs), by fueling FCVs with hydrogen produced from gasified MSW. Material and energy flows were modeled in four MSW management scenarios (incineration, landfill, gasification, gasification with recycling) and four transportation scenarios (hybrid gasoline-electric, methanol FCVs, hydrogen FCVs using hydrogen from natural gas or municipal solid waste). Technological performance deemed feasible within 2010–2020 was assumed. Greenhouse gas emissions and non-renewable energy use were used to assess overall system performance. Gasification with hydrogen production performs as efficiently as incineration, but is advantageous compared to landfilling. Taking into account additional environmental criteria, the model suggests that hydrogen from MSW gasification for FCVs may provide benefits over conventional MSW treatment and transportation systems.
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| 2. |
- Kiros, Yohannes, 1956-, et al.
(författare)
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Electrode R&D, stack design and performance of biomass-based alkaline fuel cell module
- 1999
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Ingår i: International journal of hydrogen energy. - : Pergamon Press. - 0360-3199 .- 1879-3487. ; 24, s. 549-564
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Tidskriftsartikel (refereegranskat)abstract
- Electrode formulations with di}erent materials and manufacturing techniques were tested electrochemically in order to assess their stability and activity in long!term operations. Cathode electrocatalysts such as CoTPP, Ca0.9La0.1MnO3 and Pt-Co alloys were incorporated in high surface area carbons and operated at a constant load of 100 mA cm-2 80C and an electrolyte concentration of 6M KOH. Similarly, anode catalysts with Pt-Pd bimetallic combinations were also tested and ascertained in half!cell measurements. Surface area measurements and Transmission Electron Microscopy (TEM) analyses were carried out both before and after the electrochemical test procedures. The electrodes were incorporated into a seven and two cell module design of the external and internal manifolding types and the experiences gained from these design principles are described, respectively. Furthermore, a biomass fed AFC module with all the system descriptions, steps, and a demonstration layout of producer gas to alkaline fuel cell are examined and discussed. Wood charcoal and agro-residues were used as feedstock and as a primary fuel. Power output of the different feedstock in a producer gas fed alkaline fuel cell has the shown potentiality and effciency to be applied as a stand alone power generator.
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| 3. |
- Lindström, B., et al.
(författare)
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Hydrogen generation by steam reforming of methanol over copper-based catalysts for fuel cell applications
- 2001
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Ingår i: International journal of hydrogen energy. - 0360-3199 .- 1879-3487. ; 26:9, s. 923-933
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents an investigation concerning the reforming of methanol over various base-metal oxide catalysts. Copper-based catalysts were effective for the steam reforming of methanol. The selectivity and conversion was studied in a flow reactor in the temperature interval 180-320 degreesC. The active materials were impregnated on gamma -alumina pellets using the wet impregnation method. The promoters used in the investigation were chromium (Cr), zinc (Zn) and zirconia (Zr). The copper content and promoter used played an important role in the catalyst's ability to selectively convert methanol at low temperatures. Catalysts with high copper contents generally gave higher conversions and selectivities for the steam reforming reaction. The use of ternary components generally increased the catalyst selectivity towards carbon dioxide. Zirconia had a positive influence on the catalytic performance at low temperatures. The possibilities for the use of reforming systems with copper-based catalysts in fuel cell applications are promising.
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| 4. |
- Nielsen, A.T., et al.
(författare)
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Hydrogen production from organic waste
- 2001
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Ingår i: International journal of hydrogen energy. - 0360-3199 .- 1879-3487. ; 26:6, s. 547-550
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Tidskriftsartikel (refereegranskat)abstract
- The extraction of pure hydrogen from the fermentation of household waste by a mixed anaerobic bacterial flora is demonstrated. Simulated household waste (600 g) was fermented in a bioreactor, which was continuously sparged with nitrogen (30 ml/min) fed in from the bottom. The gas stream from the biorector passes through a sulphide trap (ZnO) and then through a heated palladium-silver membrane reactor to separate hydrogen from the gas stream. In this way, waste remediation and biological hydrogen production is combined in a process where a large proportion of the hydrogen produced can be collected, free of other gaseous species from the fermentation. © 2001 International Association for Hydrogen Energy.
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| 5. |
- Pettersson, Lars J., et al.
(författare)
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State of the art of multi-fuel reformers for fuel cell vehicles : problem identification and research needs
- 2001
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Ingår i: International journal of hydrogen energy. - 0360-3199 .- 1879-3487. ; 26:3, s. 243-264
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Forskningsöversikt (refereegranskat)abstract
- This review is focused on discussions about multi-fuel reformer technology for fuel cell vehicles where techniques for onboard hydrogen generation and gas clean-up processes, as well as full considerations and emissions are included. Our conclusion is that the potential for developing a highly efficient, durable and reliable reformer system fur automotive applications is considerably higher if dedicated fuel reformers are used instead of applications where all types of fuels ranging from natural gas to heavy diesel fuels can be used. The authors propose that petroleum-derived fuels should be designed for potential use in mobile fuel cell applications. The present literature review together with site visit discussions has led to the conclusion that there are relatively low emissions from fuel cell engines compared to internal combustion engines. However, the major research work on reformers-fuel cells have been performed during steady-state operation. Emissions during start-up, shutdown and transient operation are basically unknown and must be investigated in more detail.
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| 6. |
- Abbas, Ghazanfar, et al.
(författare)
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Synthesize and characterization of nanocomposite anodes for low temperature solid oxide fuel cell
- 2015
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Ingår i: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 40:1, s. 891-897
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Tidskriftsartikel (refereegranskat)abstract
- Solid oxide fuel cells have much capability to become an economical alternative energy conversion technology having appropriate materials that can be operated at comparatively low temperature in the range of 400-600 degrees C. The nano-scale engineering has been incorporated to improve the catalytic activity of anode materials for solid oxide fuel cells. Nanostructured Al0.10NixZn0.90-xO oxides were prepared by solid state reaction, which were then mixed with the prepared Gadolinium doped Ceria GDC electrolyte. The crystal structure and surface morphology were characterized by XRD and SEM. The particle size was evaluated by XRD data and found in the range of 20-50 nm, which was then ensured by SEM pictures. The pellets of 13 mm diameter were pressed by dry press technique and electrical conductivities (DC and AC) were determined by four probe techniques and the values have been found to be 10.84 and 4.88 S/cm, respectively at hydrogen atmosphere in the temperature range of 300-600 degrees C. The Electrochemical Impedance Spectroscopy (EIS) analysis exhibits the pure electronic behavior at hydrogen atmosphere. The maximum power density of ANZ-GDC composite anode based solid oxide fuel cell has been achieved 705 mW/cm(2) at 550 degrees C.
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| 7. |
- Abutalib, M. M., et al.
(författare)
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Preparation of rGO/FeMoO4 as high-performance photocatalyst for degradation of malachite green, phenol and H2 evolution under natural sunlight
- 2022
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Ingår i: International journal of hydrogen energy. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0360-3199 .- 1879-3487. ; 47:77, s. 32955-32968
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Tidskriftsartikel (refereegranskat)abstract
- FeMoO4 and rGO/FeMoO4 nanocomposites were successfully prepared by a facile hydro-thermal method. The XRD results confirmed that the FeMoO4 has a monometallic b-FeMoO4 crystalline phase while the rGO/FeMoO4 showed both monometallic a-and b-FeMoO4 phases where b-FeMoO4 is the predominant phase. The reduction of graphene oxide (GO) to reduced graphene oxide (rGO) was performed without using any chemical reductions. UV-Vis results showed that the visible light absorption and band gap energy were enhanced after the addition of rGO. The prepared samples were successfully applied for degradation of malachite green (MG) and phenol (Ph) and for H2 evolution under natural solar light irradiation. All the nanocomposites showed higher photocatalytic activities compared with pure FeMoO4 photocatalyst, and the 10%rGO/FeMoO4 gave the highest photodegradation performance for MG and Ph and for H2 evolution. The photodegradation results revealed that the rGO content played the crucial factor in the photodegradation of MG and Ph, and H2 evolution. The mineralization (TOC), photodegradation mechanism and degradation kinetics of MG and Ph were discussed.
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| 8. |
- Adit Maark, T., et al.
(författare)
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Structural, electronic and thermodynamic properties of Al- and Si-doped α-, γ-, and β-MgH2 : Density functional and hybrid density functional calculations
- 2012
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Ingår i: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 37:11, s. 9112-9122
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we present a detailed study of Al- and Si-doped α-, γ-, and β-MgH 2 phases using the gradient corrected density functional GGA-PBE and the hybrid Hartree-Fock density functionals PBE0 and HSE06 within the framework of generalized Kohn-Sham density functional theory (DFT) using a plane-wave basis set. We investigate the structural, electronic, and thermodynamical properties of these compounds with regard to their hydrogen storage effectiveness. PBE0 and HSE06 predict cell parameters and bond lengths that are in good agreement with the GGA-PBE calculations and previously known experimental results. As expected smaller band gaps (E gs) are predicted by GGA-PBE for the pure magnesium hydride phases. PBE0 overcomes the deficiencies of DFT in treating these materials better than HSE06 and yields E gs that compare even better with previous GW calculations. Both the hybrid functionals increase the E gs of the Al-doped magnesium hydrides by much less magnitudes than of the Si-doped phases. This difference is interpreted in terms of charge density distributions. Best H 2 adsorption energies (ΔH ads) are computed by HSE06 while GGA-PBE significantly overestimates them. Si-doped α- and β-MgH 2 exhibited the least negative ΔH ads in close proximity to the H 2 binding energy range of -0.21 to -0.41 eV ideal for practical H 2 storage transportation applications.
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| 9. |
- Aftab, Umair, et al.
(författare)
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Mixed CoS2@Co3O4 composite material: An efficient nonprecious electrocatalyst for hydrogen evolution reaction
- 2020
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Ingår i: International journal of hydrogen energy. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0360-3199 .- 1879-3487. ; 45:27, s. 13805-13813
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Tidskriftsartikel (refereegranskat)abstract
- Hydrogen evolution reaction (HER) has been identified as a sustainable and environment friendly technology for a wide range of energy conversion and storage applications. The big barrier in realizing this green technology requires a highly efficient, earth-abundant, and low-cost electrocatalyst for HER. Various HER catalysts have been designed and reported, still, their performance is not up to the mark of Pt. Among them, cobalt-based, especially cobalt disulfide (CoS2) has shown significant HER activity and found suitable candidature for HER due to its low cost, simple to prepare, and exhibits good stability. Herein, we synthesized various nanostructured materials including pure CoS2, Co3O4 and their composites by wet chemical methods and found them active for HER. The scanning electron microscopy (SEM) has revealed a morphology of composite as a mixture of nanowires and round shape spherical nanoparticles with several microns in dimension. The X-ray diffraction (XRD) confirmed the cubic phase of CoS2 and cubic phase of Co3O4 in the composite materials. The chemical deposition of CoS2 onto Co3O4 has tailored the HER activity of CoS2@Co3O4 composite material. Two CoS2@Co3O4 composite materials were produced with varying amounts of Co3O4 and labeled as samples 1 and 2. The Co3O4 reduced the adsorption energy for hydrogen, decreased the aggregation of CoS2 and uplifted the stability of CoS2@Co3O4 a composite material in alkaline media. Sample 1 requires an overpotential of 320 mV to reach a current density of 10 mA/cm(2) and it exhibits a Tafel slope of 42 mVdec(-1) which is the key indicator for the fast HER kinetics on sample 1. The sample 1 is highly durable for 50 h and also it has excellent stability. The electrochemical impedance spectroscopy (EIS) revealed a small charge transfer resistance of 28.81 Ohms for the sample 1 with high capacitance double-layer value of 0.81 mF. EIS has supported polarization and Tafel slope results. Based on the partial physical characterization and the electrochemical results, the as-obtained sample 1 (CoS2@Co3O4 composite material) will find potential applications in an extended range of energy conversion and storage devices owing to its low cost, high abundance, and excellent efficiency. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
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| 10. |
- Aftab, Umair, et al.
(författare)
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Two step synthesis of TiO2–Co3O4 composite for efficient oxygen evolution reaction
- 2021
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Ingår i: International journal of hydrogen energy. - : Elsevier. - 0360-3199 .- 1879-3487. ; 46:13, s. 9110-9122
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Tidskriftsartikel (refereegranskat)abstract
- For an active hydrogen gas generation through water dissociation, the sluggish oxygen evolution reaction (OER) kinetics due to large overpotential is a main hindrance. Herein, a simple approach is used to produce composite material based on TiO2/Co3O4 for efficient OER and overpotential is linearly reduced with increasing amount of TiO2. The scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM) investigations reveal the wire like morphology of composite materials, formed by the self-assembly of nanoparticles. The titania nanoparticles were homogenously distributed on the larger Co3O4 nanoparticles. The powder x-ray diffraction revealed a tetragonal phase of TiO2 and the cubic phase of Co3O4 in the composite materials. Composite samples with increasing TiO2 content were obtained (18%, 33%, 41% and 65% wt.). Among the composites, cobalt oxide-titanium oxide with the highest TiO2 content (CT-20) possesses the lowest overpotential for OER with a Tafel slope of 60 mV dec−1 and an exchange current density of 2.98 × 10−3A/cm2. The CT-20 is highly durable for 45 h at different current densities of 10, 20 and 30 mA/cm2. Electrochemical impedance spectroscopy (EIS) confirmed the fast charge transport for the CT-20 sample, which potentially accelerated the OER kinetics. These results based on a two-step methodology for the synthesis of TiO2/Co3O4 material can be useful and interesting for various energy storage and energy conversion systems.
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