NMR Studies of the Hydrogen Storage Compound NaMgH<sub>3</sub>

Shane, David T.; Corey, R.; Bowman, Robert C.; Zidan, Ragaiy; Stowe, Ashley C.; Hwang, Son‐Jong; Kim, Chul; Conradi, Mark S.

doi:10.1021/jp906414q

Cited by 25 publications

(18 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Figure 9 shows the pure frequency dependence of the NMR spectrum rather than the magnetic field effect. Measurement at a higher Larmor frequency pro- The temperature-induced 1 H NMR spectra and the two-component spectra have been observed for MgH 2 [3], LiBH 4 [4], NaMgH 3 [5], NaH [6], and the KH 2 PO 4 family [7,8].…”

Section: Nmr Spectra With Variable Larmor Frequencymentioning

confidence: 94%

“…Ionic conduction facilitated by lattice defects also causes the narrowing of the NMR spectra [2]. The development of a narrow NMR spectrum superposed with a broad NMR spectrum has been observed for some hydrates [3][4][5][6], hydrogen-bonded compounds [7,8], and nanocrystalline Li compounds [9][10][11]. The broad component is assigned to immobile ions with dipole-dipole couplings on a rigid lattice, while the narrow component is assigned to mobile ions decoupled from the matrix of each material.…”

Section: Introductionmentioning

confidence: 98%

See 1 more Smart Citation

Extrinsic Proton NMR Studies of Mg(OH)₂ and Ca(OH)₂

Itoh

Isobe

2016

J. Phys. Soc. Jpn.

View full text Add to dashboard Cite

We studied narrow 1 H NMR spectra of Mg(OH)2 and Ca(OH)2 powders at 100−355 K and 42−59 MHz using pulsed NMR techniques. The Fourier transformed NMR spectra of the proton freeinduction signals show the superposition of broad and narrow components, which can be assigned to immobile protons and extrinsic mobile protons, respectively. We found that a narrow spectrum develops on heating above about Tc = 260 K and widens above a Larmor frequency of about νc = 50 MHz for Mg(OH)2. The temperature-induced NMR spectrum and the characteristic frequency νc of 50 MHz are the noteworthy features of the nuclear spin fluctuation spectra of the extrinsic protons.

show abstract

Section: Nmr Spectra With Variable Larmor Frequencymentioning

confidence: 94%

Section: Introductionmentioning

confidence: 98%

Extrinsic Proton NMR Studies of Mg(OH)₂ and Ca(OH)₂

Itoh

Isobe

2016

J. Phys. Soc. Jpn.

View full text Add to dashboard Cite

show abstract

“…10) The NMR spectrum from the composite FID is confirmed to be nearly identical to the magic-echo spectrum for some hydrides, 10) and then the extrapolation procedure has been applied to various hydrogen compounds. [14][15][16][17] In this paper, we adopted a replacement procedure to analyze the proton FID for Mg(OH) 2 and Ca(OH) 2 , which made the FT-NMR analysis better than that in a previous report. 6) The portion of the FID obscured by probe ringing and/or dead time was replaced by the extrapolated data using an analytical fitting function.…”

Section: Introductionmentioning

confidence: 99%

Intrinsic Proton NMR Studies of Mg(OH)₂ and Ca(OH)₂

Itoh¹,

Isobe²

2016

J. Phys. Soc. Jpn.

View full text Add to dashboard Cite

We studied the short proton free induction decay signals and the broad 1 H NMR spectra of Mg(OH) 2 and Ca(OH) 2 powders at 77−355 K and 42 MHz using pulsed NMR techniques. Using a Gaussian-type back extrapolation procedure for the obscured data of the proton free induction decay signals, we obtained more precise values of the second moments of the Fourier-transformed broad NMR spectra than those in a previous report [Y. Itoh and M. Isobe, J. Phys. Soc. Jpn. 84, 113601 (2015)] and compared with the theoretical second moments. The decrease in the second moment could not account for the large decrease in the magnitude of the intrinsic proton spin-lattice relaxation rate 1/T 1 from Mg(OH) 2 to Ca(OH) 2 . The analysis of 1/T 1 ∝ exp(−E g /k B T ) with E g ∼ 0.01 eV points to a local hopping mechanism, and that of 1/T 1 ∝ T n with n ∼ 0.5 points to an anharmonic rattling mechanism.

show abstract

“…Recently, it has been found that NaH hydride addition greatly improves the hydrogen storage properties of MgH 2 because of the formation of NaMgH 3 [ 19 ]. Fast hydrogen mobility in NaMgH 3 has been revealed by H NMR study and related to its perovskite structure [ 20 ]. Therefore, it is believed that, in a mixture of MgH 2 and NaMgH 3 , hydrogen gas adsorption and dissociation are activated by NaMgH 3 grains which offer fast diffusion pathway for hydrogen atoms into MgH 2 [ 16 , 19 ].…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic Modeling of Hydrogen Storage Capacity in Mg-Na Alloys

Abdessameud

Mezbahul-Islam

Medraj

2014

The Scientific World Journal

View full text Add to dashboard Cite

Thermodynamic modeling of the H-Mg-Na system is performed for the first time in this work in order to understand the phase relationships in this system. A new thermodynamic description of the stable NaMgH 3 hydride is performed and the thermodynamic models for the H-Mg, Mg-Na, and H-Na systems are reassessed using the modified quasichemical model for the liquid phase. The thermodynamic properties of the ternary system are estimated from the models of the binary systems and the ternary compound using CALPHAD technique. The constructed database is successfully used to reproduce the pressure-composition isotherms for MgH 2 + 10 wt.% NaH mixtures. Also, the pressure-temperature equilibrium diagram and reaction paths for the same composition are predicted at different temperatures and pressures. Even though it is proved that H-Mg-Na does not meet the DOE hydrogen storage requirements for onboard applications, the best working temperatures and pressures to benefit from its full catalytic role are given. Also, the present database can be used for thermodynamic assessments of higher order systems.

show abstract

NMR Studies of the Hydrogen Storage Compound NaMgH₃

Cited by 25 publications

References 32 publications

Extrinsic Proton NMR Studies of Mg(OH)₂ and Ca(OH)₂

Extrinsic Proton NMR Studies of Mg(OH)₂ and Ca(OH)₂

Intrinsic Proton NMR Studies of Mg(OH)₂ and Ca(OH)₂

Thermodynamic Modeling of Hydrogen Storage Capacity in Mg-Na Alloys

Contact Info

Product

Resources

About

NMR Studies of the Hydrogen Storage Compound NaMgH3

Cited by 25 publications

References 32 publications

Extrinsic Proton NMR Studies of Mg(OH)2 and Ca(OH)2

Extrinsic Proton NMR Studies of Mg(OH)2 and Ca(OH)2

Intrinsic Proton NMR Studies of Mg(OH)2 and Ca(OH)2

Thermodynamic Modeling of Hydrogen Storage Capacity in Mg-Na Alloys

Contact Info

Product

Resources

About

NMR Studies of the Hydrogen Storage Compound NaMgH₃

Extrinsic Proton NMR Studies of Mg(OH)₂ and Ca(OH)₂

Extrinsic Proton NMR Studies of Mg(OH)₂ and Ca(OH)₂

Intrinsic Proton NMR Studies of Mg(OH)₂ and Ca(OH)₂