Papers by Keyword: Hydrogen Storage

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Authors: Gisele Ferreira De Lima, Mauricio Mhirdaui Peres, Sebastiano Garroni, Maria Dolors Barò, Santiago Surinyach, Claudio Shyinti Kiminami, Claudemiro Bolfarini, Walter José Botta Filho, Alberto Moreira Jorge
Abstract: Samples of a 2Mg-Fe (at.%) mixture were produced by high energy ball-milling (HEBM) with ball to powder ratio = 20:1, in an argon gas atmosphere, in 190 ml vials (sample-1) to produce powders and in 300 ml vials (sample-2) to produce plates. Both samples were cold-pressed into preforms. The preforms were then extruded at 300°C at a ram speed of 1mm/min., with the following extrusion ratios: sample-1 at 3/1 to ensure porosity and sample-2 at 5/1 to increase the adhesion of the plates. The resulting bulks from samples 1 and 2 were hydrogenated for 24h in a reactor under 15 bar of H2 to produce the Mg2FeH6 complex hydride, and at 11 bar of H2 to produce both the complex hydride and MgH2 hydride. In addition, sample-1 was severely temperature-hydrogen cycled to verify its microstructural stability and the influence of grain size on the sorption properties. XRD patterns showed Mg(hc), Fe(ccc) and Mg2FeH6 in both samples, and sample-2 also contained MgH2 and MgO (attributed to processing contamination). DSC results demonstrated that the initial desorption temperature of sample-1 was lower than that of sample-2. However, sample-2 showed faster desorption kinetics, presenting a desorption peak about 73°C below that of sample-1. This could be attributed to the activation/catalyst effect of the MgH2 hydride. The improvement in sorption properties was attributed mainly to porosity and to the type of employed catalysts.
Authors: Shi Chun Mu, M. Pan, Run Zhang Yuan
Abstract: Some minerals were considered to store hydrogen on the basis of their porous crystal structure. Besides of crystal graphite and zeolite, some natural clay minerals such as palygorskite-sepiolite minerals with nano-scale channels and polar surface can also store hydrogen. The hydrogen storage mechanism of porous minerals was discussed. The experimental results showed a potential application of palygorskite-sepiolite minerals as the media of hydrogen storage.
Authors: Mirko Kunowsky, Juan Pablo Marco-Lozar, Ángel Linares-Solano
Abstract: Porous adsorbents are currently investigated for hydrogen storage application. From a practical point of view, in addition to high porosity developments, high material densities are required, in order to confine as much material as possible in a tank device. In this study, we use different measured sample densities (tap, packing, compacted and monolith) for analyzing the hydrogen adsorption behavior of activated carbon fibres (ACFs) and activated carbon nanofibres (ACNFs) which were prepared by KOH and CO2 activations, respectively. Hydrogen adsorption isotherms are measured for all of the adsorbents at room temperature and under high pressures (up to 20 MPa). The obtained results confirm that (i) gravimetric H2 adsorption is directly related to the porosity of the adsorbent, (ii) volumetric H2 adsorption depends on the adsorbent porosity and importantly also on the material density, (iii) the density of the adsorbent can be improved by packing the original adsorbents under mechanical pressure or synthesizing monoliths from them, (iv) both ways (packing under pressure or preparing monoliths) considerably improve the storage capacity of the starting adsorbents, and (v) the preparation of monoliths, in addition to avoid engineering constrains of packing under mechanical pressure, has the advantage of providing high mechanical resistance and easy handling of the adsorbent.
Authors: Ye Lu He, Ding Xing Liu, Yong Qu, Zhen Yao
Abstract: The adsorption hydrogen molecule on intrinsic and Al-doped graphene was studied by density functional theory calculations. The results show that the intrinsic graphene is not an ideal hydrogen storage material. Compared with the intrinsic, H2 molecules are stongly adsorbed onto the Al-doped graphene with higher adsorbed energy and shorter distance between H2 and surface. The band structure and density of states results show that between hydrogen and other atoms, the charge transfers are apparent increased. All are help for hydrogen adsorption. Therefore, Al-doped graphene is a promising candidate for hydrogen storage material.
Authors: Kazuhide Ichikawa, Yuji Ikeda, Ryo Terashima, Akitomo Tachibana
Abstract: We study the chemical bonds of small Al clusters (Aln, n=2-8) and hydrogenated Al clusters (AlnHm , n=1-8 and m=1,2) using electronic stress tensor. We calculate the bond order based on energy density for these clusters. We also study the electronic structure under the presence of electronic current by the electronic stress tensor for AlH3 molecule.
Authors: Cong Wang, Hong Li Wang, Da Wei Gao, Zhan Kui Zhao
Abstract: Hydrous hydrazine is a promising hydrogen carrier material because of its high content of hydrogen (8.0 wt.%) and easy recharging as a liquid. Amorphous Ni8.1Co1.0Pt0.9/Ce2O3 nanoparticles with low precious-metal content were synthesized by a facile co-reduction method at room temperature under ambient atmosphere. The increased degree of amorphization was attributed to the introduction of Ce2O3. The resultant Ni8.1Co1.0Pt0.9/Ce2O3 nanocomposite was employed as an efficient nanocatalyst towards the decomposition of hydrous hydrazine to H2, and exhibited excellent catalytic activity and 100% H2 selectivity. Turnover frequency (TOF) value catalyzed by amorphous Ni8.1Co1.0Pt0.9/Ce2O3 is 93.75 h-1, which is much higher than Ni8.1Co1.0Pt0.9 (4.39 h-1) at 298 K. The development of the improved catalytic performance and low-cost catalyst with amorphous structure is believed to strongly promote the practical application of hydrous hydrazine as a hydrogen storage material.
Authors: Viktor N. Kudiiarov, Luydmila V. Gulidova, Natalia S. Pushilina, Andrey M. Lider
Abstract: Automated complex Gas Reaction Controller and its application for hydrogen storage materials investigation are described in this article. Pressure-composition isotherms (PCI) and kinetics measurements of LaNi5 have been obtained for validation of the apparatus. Measurements of both absorption and desorption PCI curves and kinetics measurements at different conditions have been obtained for carbon nanotubes to estimate its hydrogen storage properties.
Authors: Il Ho Kim, Won Sik Lee, Se Hyun Ko, Jin Man Jang, Ho Sung Kim
Abstract: The open cell Al (or Al foam) was employed in the alloy hydride system due to the rapid heat conductivity of Al. The hydrogen storage alloy powders were packed in this storage system made of Al open cell, and the changes of temperature and equilibrium pressure of hydrogen desorbed were measured. By applying the open cell Al in this hydrogen storage system, the reaction sensitivity of the temperature and equilibrium pressure was far rapidly increased than that without the open cell Al.
Authors: Amir Al-Ahmed, Bello Mukhtar, Safdar Hossain, S.M. Javaid Zaidi, S.U. Rahman
Abstract: Tremendous amount of research work is going on Titanium dioxide (TiO2) based materials. These materials have many useful applications in our scientific and daily life and it ranges from photovoltaics to photocatalysis to photo-electrochromics, sensors etc.. All these applications can be divided into two broad categories such as environmental (photocatalysis and sensing) and energy (photovoltaics, water splitting, photo-/electrochromics, and hydrogen storage). Synthesis of TiO2 nanoparticles with specific size and structural phase is crucial, for solar sell application. Monodispersed spherical colloids with minimum size variation (5% or less) is essential for the fabrication of photonic crystals. When sensitized with organic dyes or inorganic narrow band gap semiconductors, TiO2 can absorb light into the visible light region and convert solar energy into electrical energy for solar cell applications. TiO2 nanomaterials also have been widely studied for water splitting and hydrogen production due to their suitable electronic band structure given the redox potential of water. Again nanostructured TiO2 has extensively been studied for hydrogen storage with good storage capacity and easy releasing procedure. All these issues and related finding will be discussed in this review.
Authors: Xing Yu Cui, Ning Zhang, Pu Yu Yao, Bin Liang
Abstract: Hollow micro/nanosphere materials have the especial structure, excellent physical and chemical properties, so they have the broad application prospect in some fields, such as energy conservation, environmental protection, new energy and so on. This paper summarizes the adhibition of hollow micro/nanosphere materials in energy conservation, environmental protection, new energy and so on. And this paper prospects the research area and application prospect of the hollow micro/nanosphere material.
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