SYNTHESIS AND HYDROGEN ABSORPTION KINETICS OF V4Cr4Ti ALLOY
01 Apr 2013-Journal of Thermal Analysis and Calorimetry (Springer Netherlands)-Vol. 112, Iss: 1, pp 51-57
TL;DR: In this article, the hydrogen absorption characteristics of V4Cr4Ti alloy have been evaluated by measuring the pressure composition isotherm (PCIT) at 57°C temperature.
Abstract: V4Cr4Ti alloy is synthesized by aluminothermy process followed by electron beam refining. Hydrogen absorption characteristics of the alloy have been evaluated by measuring the pressure composition isotherm (PCIT) at 57 °C temperature. Two plateau pressures are observed in the PCIT curve. Substantial decrease in the hydrogen absorption capacity of the alloy as compared to vanadium has been recorded. Hydrogen absorption kinetics of the alloy was investigated in the temperature range of 200–500 °C. Three-dimensional diffusion appears to be the rate controlling step of the hydrogen absorption. The apparent activation energy was calculated as 0.16 eV/atom-hydrogen.
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TL;DR: In this paper, a systematic review of vanadium as a base material for hydrogen storage and permeation membrane is presented, where the vanadium has shown high hydrogen solubility and diffusivity at nominal temperature and pressure conditions.
Abstract: The metallic vanadium has an excellent hydrogen storage properties in comparison to other hydride forming metals such as titanium, uranium, and zirconium. The gravimetric storage capacity of vanadium is over 4 wt% which is even better than AB2 and AB5 alloys. The metallic vanadium has shown high hydrogen solubility and diffusivity at nominal temperature and pressure conditions. Consequently, vanadium is under consideration for the cost-effective hydrogen permeation membrane to replace palladium. The issues with vanadium are poor reversibility and pulverization. The poor reversibility is because of high thermal stability of β (VH/V2H) phase which eventually restricts the cyclic hydrogen storage capacity up to 2 wt% at room temperature. The pulverization is because of large crystal misfit between the metal and metal hydride phase. The hydrogen solubility, phase stability, hydrogenation-dehydrogenation kinetics, and pulverization are highly influenced by the presence of an alloying element. Therefore, worldwide efforts are to explore and optimize the alloying element which could enhance the hydrogen solubility, destabilized the β phase, improved the hydrogenation-dehydrogenation kinetics, and prevent the pulverization. The current review is a systematic presentation of these efforts to resolve the issues of vanadium as a base material for hydrogen storage and permeation membrane.
135 citations
TL;DR: In this paper, the crystal structure of FeTi intermetallic and FeTi-3.1 mass % V alloy was studied in a thermobalance attached to a Sieverts apparatus at a temperature of 327 K under 0.2 MPa hydrogen pressure.
51 citations
TL;DR: In this article, the thermodynamics and kinetics of hydrogen absorption and desorption of nfTa2O5-Mg-H2 composite have been studied and shown cyclic stability up to fifty hydrogen absorption-desorption without significant changes in the kinetics and hydrogen storage capacity.
Abstract: The thermodynamics and kinetics of hydrogen absorption–desorption of nfTa2O5–Mg–MgH2—composite (nf stands for nano-flakes) have been studied. The nfTa2O5–Mg composite could absorb hydrogen at room temperature (17 °C). The hydrogen desorption of nfTa2O5–MgH2 composite starts at 200 °C. The remarkably improved hydrogen absorption–desorption of catalyzed Mg–MgH2 could be attributed to the nano-engineered surface by nfTa2O5. The enthalpies of hydrogen absorption–desorption were found to be 80 ± 2, and 76 ± 3 kJ/mol respectively.
The activation energy of hydrogen absorption was evaluated as 49 ± 5 kJ/mol which is same as the energy barrier for diffusion of hydrogen in Mg matrix. The apparent activation of hydrogen desorption of nfTa2O5–MgH2 was found to be 74 ± 7 kJ/mol. The nfTa2O5–MgH2 composite has shown cyclic stability up to fifty hydrogen absorption–desorption without significant changes in the kinetics and hydrogen storage capacity.
39 citations
TL;DR: In this paper, the authors studied the thermodynamics and kinetics of hydrogenation-dehydrogenation of nanometric iron (nFe) doped Mg-MgH 2 system.
38 citations
15 Dec 2020
TL;DR: In this paper, a brief overview of partial substitution in several AxBy alloys, from the long-established AB5 and AB2-types, to the recently attractive and extensively studied AB and AB3 alloys including the largely documented solid-solution alloy systems, is presented.
Abstract: Solid-state hydrogen storage covers a broad range of materials praised for their gravimetric, volumetric and kinetic properties, as well as for the safety they confer compared to gaseous or liquid hydrogen storage methods. Among them, AxBy intermetallics show outstanding performances, notably for stationary storage applications. Elemental substitution, whether on the A or B site of these alloys, allows the effective tailoring of key properties such as gravimetric density, equilibrium pressure, hysteresis and cyclic stability for instance. In this review, we present a brief overview of partial substitution in several AxBy alloys, from the long-established AB5 and AB2-types, to the recently attractive and extensively studied AB and AB3 alloys, including the largely documented solid-solution alloy systems. We not only present classical and pioneering investigations, but also report recent developments for each AxBy category. Special care is brought to the influence of composition engineering on desorption equilibrium pressure and hydrogen storage capacity. A simple overview of the AxBy operating conditions is provided, hence giving a sense of the range of possible applications, whether for low- or high-pressure systems.
32 citations
References
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TL;DR: Recent developments in the search for innovative materials with high hydrogen-storage capacity are presented.
Abstract: Mobility — the transport of people and goods — is a socioeconomic reality that will surely increase in the coming years. It should be safe, economic and reasonably clean. Little energy needs to be expended to overcome potential energy changes, but a great deal is lost through friction (for cars about 10 kWh per 100 km) and low-efficiency energy conversion. Vehicles can be run either by connecting them to a continuous supply of energy or by storing energy on board. Hydrogen would be ideal as a synthetic fuel because it is lightweight, highly abundant and its oxidation product (water) is environmentally benign, but storage remains a problem. Here we present recent developments in the search for innovative materials with high hydrogen-storage capacity.
7,414 citations
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"SYNTHESIS AND HYDROGEN ABSORPTION K..." refers background in this paper
...In the search of an alternative energy option, hydrogen as an energy carrier emerges as a promising, renewable, and eco-friendly option for transportation and domestic applications [1, 2]....
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