The effect of the partial replacement of nickelin LaNi5 hydride with iron, cobalt, and copper on absorption and desorption kinetics

Zarynow, A.; Goudy, A.J.; Schweibenz, R.G.; Clay, K.R.

doi:10.1016/s0022-5088(06)80006-8

Cited by 31 publications

(16 citation statements)

References 5 publications

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“…Considerable changes in the thermodynamic properties of a binary hydride, MgH 2 for instance, can be achieved by forming ternary or multinary hydrides, e.g., Mg 2 NiH 4 . [8,9] Similar approaches could be applicable to nitride and imide systems. However, since there is a lack of previous literature, elucidation of the synthetic method, material structure and chemical properties, and the hydrogen storage mechanism etc.…”

Section: Methodsmentioning

confidence: 99%

“…We therefore had to calculate it from the experimental adsorbed amount (surface excess mass). [8] We assumed that the adsorbed-methane density is given by [9] q ad = (C/V 0 ) + q bulk (1) where q ad (g L ±1 ) is the adsorbed-methane density, C (mg g ±1 ) is the experimental adsorbed-methane amount, V 0 (mL g ±1 ) is the pore volume of the SWNH, and q bulk is the density of methane in the bulk gas phase.Sample Preparation: The SWNH was synthesized by CO 2 laser ablation of graphite under Ar gas at 101 kPa [1]. Lanthanide nitrates were dispersed on the as-grown SWNH as lanthanide nitrate solution.…”

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confidence: 99%

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Ternary Imides for Hydrogen Storage

et al. 2004

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(see Fig. 2 in the Supporting Information): a large heat of adsorption means greater stabilization of the adsorbed methane. The heat of adsorption of methane by europium-nitrate-dispersed SWNH at all density regions of adsorbed methane is greater than that of an as-grown SWNH by 40±90 meV.In conclusion, we have obtained the following results:d 1) A small amount of dispersed lanthanides strongly enhances the methane adsorption.d 2) Adsorbed methane molecules are stabilized by dispersed lanthanide nitrates on the SWNH.This enhancement effect of methane storage is only observed with carbon nanohorns (see Supporting Information). Currently we have only applied this method to as-grown SWNHs. However, enhancement of gas adsorption by charge transfer is promising as a means for achieving practical methane storage. ExperimentalObservation by STEM: The sample of europium-nitrate-dispersed SWNHs was put on a holey carbon grid disk and observed by a scanning transmission electron microscope (HD2000-UHV, Hitachi, 120 kV).Determination of Pore Volume of SWNHs: After pretreatment at 423 K and 1 mPa, the pore volume of the SWNHs was determined volumetrically by a nitrogen-adsorption isotherm at 77 K with a volumetric apparatus (Autosorb 1, Quantachrome) [2]. The nitrogen-adsorption isotherms were analyzed with the a s -method described by Sing [6]. The specific surface areas and micropore volumes of SWNH samples are shown in Table 1.Methane Adsorption: We measured the amount of methane adsorbed by a gravimetric method at 303 K by using an electric microbalance (Cahn 1100) [7] with a resolution of 0.1 lg. In order to remove adsorbed gases and water, a pretreatment was performed at a pressure of less than 1 mPa and temperature of 423 K for 2 h prior to the adsorption measurement.The adsorbed-methane density could not be obtained directly from the experiments. We therefore had to calculate it from the experimental adsorbed amount (surface excess mass). [8] We assumed that the adsorbed-methane density is given by [9] q ad = (C/V 0 ) + q bulk (1) where q ad (g L ±1 ) is the adsorbed-methane density, C (mg g ±1 ) is the experimental adsorbed-methane amount, V 0 (mL g ±1 ) is the pore volume of the SWNH, and q bulk is the density of methane in the bulk gas phase.Sample Preparation: The SWNH was synthesized by CO 2 laser ablation of graphite under Ar gas at 101 kPa [1]. Lanthanide nitrates were dispersed on the as-grown SWNH as lanthanide nitrate solution. The SWNH was mixed with an ethanolic lanthanide nitrate solution and this mixture was sonicated for five minutes. Finally, the mixture of lanthanide nitrate solution and SWNH was dried at room temperature for a week.Received Ternary Imides for Hydrogen Storage** By Zhitao Xiong, Guotao Wu, Jianjiang Hu, and Ping Chen*The demand for highly efficient solid-state hydrogen storage materials for the coming hydrogen economy has encouraged tremendous efforts in the development of novel systems such as complex chemical hydrides and carbonaceous materials.[1±4] Metal nitrides and imides, newc...

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Section: Methodsmentioning

confidence: 99%

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confidence: 99%

Ternary Imides for Hydrogen Storage

et al. 2004

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“…Using equation (12), p eq is calculated to be 0.13 MPa. This pressure ratio N has been widely used in hydriding kinetics studies [4,9,24]. From a qualitative point of view, the molar entropy generation varies slightly at pressure ratio varying from 2.3 to 3.84 no matter how large the convective heat transfer coefficient is.…”

Section: Resultsmentioning

confidence: 99%

Assessment of errors on the kinetic data by entropy generation analysis

Nyamsi

Yang

et al. 2012

International Journal of Hydrogen Energy

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“…This decrease in the activation energy can be attributed towards the higher affinity of La (a major constituent of the Mm being used) to hydrogen and hence lower energy required to achieve the process. When the phase hydride is formed completely, the diffusion of hydrogen should constitute the rate determining step [24,25] and therefore this is the case for the second linear region of the fit shown in Fig. 6.…”

Section: Hydrogen Absorption Kineticsmentioning

confidence: 94%