Evidence of Intermediate Hydrogen States in the Formation of a Complex Hydride

doi:10.1021/acs.inorgchem.7b02834

Title: Evidence of Intermediate Hydrogen States in the Formation of a Complex Hydride

Abstract

A complex hydride (LaMg₂NiH₇) composed of La³⁺, two Mg²⁺, [NiH₄]^4– with a covalently bonded hydrogen, and three H^– was formed from an intermetallic LaMg₂Ni via an intermediate phase (LaMg₂NiH_4.6) composed of La, Mg, NiH₂, NiH₃ units, and H atoms at tetrahedral sites. The NiH₂ and NiH₃ units in LaMg₂NiH_4.6 were reported as precursors for [NiH₄]^4– in LaMg₂NiH⁷ [Miwa et al. J. Phys. Chem. C 2016, 120, 5926–5931]. To further understand the hydrogen states in the precursors (the NiH₂ and NiH₃ units) and H atoms at the tetrahedral sites in the intermediate phase, LaMg₂NiH_4.6, we observed the hydrogen vibrations in LaMg₂NiH_4.6 and LaMg₂NiH₇ by using inelastic neutron scattering. A comparison of the hydrogen vibrations of the NiH₂ and NiH₃ units with that of [NiH₄]^4– shows that the librational modes of the NiH₂ and NiH₃ units were nonexistent; librational modes are characteristic modes for complex anions, such as [NiH₄]^4–. Furthermore, the hydrogen vibrations for the H atoms in the tetrahedral sites showed a narrower wavenumber range than that for H^– and a wider range than that for typical interstitial hydrogen. The results indicated the presence of intermediate hydrogen states before the formation of [NiH₄]^4– and H^–.

Authors:

^[1]; Ramirez-Cuesta, Anibal J. ^[2]; Daemen, Luke L. ^[3]; Cheng, Yongqiang ^[3]; Orimo, Shin-ichi ^[4]

Tohoku Univ., Sendai (Japan). Inst. for Materials Research
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical and Engineering Materials Division, Neutron Sciences Directorate
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical and Engineering Materials Division, Neutron Sciences Directorate
Tohoku Univ., Sendai (Japan). Inst. for Materials Research; Tohoku Univ., Sendai (Japan). WPI-Advanced Inst. for Materials Research

Publication Date:: 2017-12-26

Research Org.:: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); USDOE Laboratory Directed Research and Development (LDRD) Program; Japan Society for the Promotion of Science (JSPS)

OSTI Identifier:: 1422532

Grant/Contract Number:: AC05-00OR22725; 16K06766; 25220911

Resource Type:: Accepted Manuscript

Journal Name:: Inorganic Chemistry

Additional Journal Information:: Journal Volume: 57; Journal Issue: 2; Journal ID: ISSN 0020-1669

Publisher:: American Chemical Society (ACS)

Country of Publication:: United States

Language:: English

Subject:: 36 MATERIALS SCIENCE; Inelastic neutron scattering; complex hydride; hydrogen state

Citation Formats


                    Sato, Toyoto, Ramirez-Cuesta, Anibal J., Daemen, Luke L., Cheng, Yongqiang, and Orimo, Shin-ichi. Evidence of Intermediate Hydrogen States in the Formation of a Complex Hydride.  United States: N. p., 2017. 
        Web.  doi:10.1021/acs.inorgchem.7b02834.

Copy to clipboard


                    Sato, Toyoto, Ramirez-Cuesta, Anibal J., Daemen, Luke L., Cheng, Yongqiang, & Orimo, Shin-ichi. Evidence of Intermediate Hydrogen States in the Formation of a Complex Hydride.  United States.  doi:10.1021/acs.inorgchem.7b02834.

Copy to clipboard


                    Sato, Toyoto, Ramirez-Cuesta, Anibal J., Daemen, Luke L., Cheng, Yongqiang, and Orimo, Shin-ichi. Tue .  
        "Evidence of Intermediate Hydrogen States in the Formation of a Complex Hydride".  United States.  doi:10.1021/acs.inorgchem.7b02834.  https://www.osti.gov/servlets/purl/1422532.

Copy to clipboard


                    
@article{osti_1422532,

  title        = {Evidence of Intermediate Hydrogen States in the Formation of a Complex Hydride},

  author       = {Sato, Toyoto and Ramirez-Cuesta, Anibal J. and Daemen, Luke L. and Cheng, Yongqiang and Orimo, Shin-ichi},

  abstractNote = {A complex hydride (LaMg2NiH7) composed of La3+, two Mg2+, [NiH4]4– with a covalently bonded hydrogen, and three H– was formed from an intermetallic LaMg2Ni via an intermediate phase (LaMg2NiH4.6) composed of La, Mg, NiH2, NiH3 units, and H atoms at tetrahedral sites. The NiH2 and NiH3 units in LaMg2NiH4.6 were reported as precursors for [NiH4]4– in LaMg2NiH7 [Miwa et al. J. Phys. Chem. C 2016, 120, 5926–5931]. To further understand the hydrogen states in the precursors (the NiH2 and NiH3 units) and H atoms at the tetrahedral sites in the intermediate phase, LaMg2NiH4.6, we observed the hydrogen vibrations in LaMg2NiH4.6 and LaMg2NiH7 by using inelastic neutron scattering. A comparison of the hydrogen vibrations of the NiH2 and NiH3 units with that of [NiH4]4– shows that the librational modes of the NiH2 and NiH3 units were nonexistent; librational modes are characteristic modes for complex anions, such as [NiH4]4–. Furthermore, the hydrogen vibrations for the H atoms in the tetrahedral sites showed a narrower wavenumber range than that for H– and a wider range than that for typical interstitial hydrogen. The results indicated the presence of intermediate hydrogen states before the formation of [NiH4]4– and H–.},

  doi          = {10.1021/acs.inorgchem.7b02834},

  journal      = {Inorganic Chemistry},

  number       = 2,

  volume       = 57,

  place        = {United States},

  year         = {2017},

  month        = {12}

}

Copy to clipboard

Journal Article:

Free Publicly Available Full Text

Accepted Manuscript (DOE)

Publisher's Version of Record

DOI: 10.1021/acs.inorgchem.7b02834

Other availability

Search WorldCat to find libraries that may hold this journal

Citation Metrics:

Cited by: 1 work

Citation information provided by
Web of Science

Figures / Tables:

Figure 1: Crystal structures of (a) LaMg₂NiH₇ and (b) LaMg₂NiH_4.6. Gray, orange, green, blue, and cyan circles and cyan tetrahedra indicate La, Mg, Ni, H (H^cov.), and H⁻ (H^tet.) atoms and the tetrahedral sites of H⁻ (H^tet.), respectively. The local atomic structures around Ni ([NiH₄]⁴⁻, NiH_1.9, and NiH_3.3) and Hmore »

All figures and tables (3 total)

Save / Share:

Export Metadata

Save to My Library

Figures / Tables found in this record:

Figure 1 (p. 2)

Figure 2 (p. 4)

Figure 3 (p. 5)

Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.

Similar Records in DOE PAGES and OSTI.GOV collections:

Mg substitution effect on the hydrogenation behaviour, thermodynamic and structural properties of the La{sub 2}Ni{sub 7}-H(D){sub 2} system

Journal Article Denys, R V ; Riabov, A B ; Physico-Mechanical Institute of the National Academy of Science of Ukraine, 5 Naukova St., Lviv 79601 ; ... - Journal of Solid State Chemistry

The present work is focused on studies of the influence of magnesium on the hydrogenation behaviour of the (La,Mg){sub 2}Ni{sub 7} alloys. Substitution of La in La{sub 2}Ni{sub 7} by Mg to form La{sub 1.5}Mg{sub 0.5}Ni{sub 7} preserves the initial Ce{sub 2}Ni{sub 7} type of the hexagonal P6{sub 3}/mmc structure and leads to contraction of the unit cell. The system La{sub 1.5}Mg{sub 0.5}Ni{sub 7}-H{sub 2} (D{sub 2}) was studied using in situ synchrotron X-ray and neutron powder diffraction in H{sub 2}/D{sub 2} gas and pressure-composition-temperature measurements. La replacement by Mg was found to proceed in an ordered way, only withinmore »« less
DOI: 10.1016/j.jssc.2007.12.041
Investigations on hydrogen storage properties of Mg{sub 2}Ni+x wt% LaMg{sub 2}Ni (x=0, 10, 20, 30) composites

Journal Article Xin, Zhao ; College of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004 ; Han Shumin, E-mail: hanshm@ysu.edu.cn ; ... - Journal of Solid State Chemistry

Mg{sub 2}Ni+x wt% LaMg{sub 2}Ni (x=0, 10, 20, 30) composites have been prepared by ball milling Mg{sub 2}Ni and LaMg{sub 2}Ni hydrides. X-ray Diffraction indicates that the composites consist of LaH{sub 3} and Mg{sub 2}NiH{sub 4} phases. Mg{sub 2}NiH{sub 4} phase transforms between with Mg{sub 2}Ni phase during hydriding/dehydriding cycling, while the LaH{sub 3} phase exists still after dehydriding process. Backscatter Electron results reveal that the LaH{sub 3} phase, which is decomposed from hydrided LaMg{sub 2}Ni, distributes in Mg{sub 2}Ni alloy homogeneously after ball milling procedure. Hydriding/Dehydriding measurements indicate significant improvement in reversible hydrogen storage properties of the composites overmore »« less
DOI: 10.1016/J.JSSC.2012.02.010
Crystal phases, defects, and dynamics of adsorbed hyroxyl groups and water in pure and lanthanide-modified zirconia: A neutron-scattering study

Journal Article Loong, C K ; Richardson, Jr, J W ; Ozawa, Masakuni - Journal of Catalysis

The role of lanthanide doping in zirconia as a means of stabilizing and promoting catalytic reactions was studied by neutron spectroscopy. The crystal structure of high-surface-area Ln{sub 0.1}Zr{sub 0.9}O{sub 1.95}(Ln = La and Nd) powders prepared by a coprecipitation method were found to be composed of mixed phases of tetragonal and cubic symmetry, which can be stabilized over a temperature range (up to {approximately}1000{degrees}C) pertinent to catalytic applications. A real-space correlation function, obtained from a Fourier transform of the filtered residual diffuse scattering, showed evidence of static, oxygen vacancy-induced atomic displacements along the pseudocubic <111> and other directions. The dynamicsmore »« less
DOI: 10.1006/jcat.1995.1329
Characterization of NH/sub 4/-rho and vacuum-calcined H-rho zeolites by multinuclear NMR spectroscopy

Journal Article Vega, A J ; Luz, Z - J. Phys. Chem.; (United States)

Proton spin counting NMR is used to follow the vacuum calcination of the zeolite NH/sub 4/-rho. Based on these results a two-step vacuum-calcination procedure for the preparation of H-rho is proposed. It consists of heating for 20 h at 80 /sup 0/C followed by 7 h at 450 /sup 0/C. A multinuclear NMR study is then performed in order to characterize the anhydrous and hydrated forms of NH/sub 4/- and H-rho. The techniques include /sup 27/Al, /sup 29/Si, and /sup 1/H magic-angle spinning (MAS), /sup 1/H and /sup 27/Al spin counting, quadrupole-echo deuterium NMR of deuterated samples, as well asmore »« less
DOI: 10.1021/j100286a025
Lattice dynamics, Raman spectroscopy, and inelastic neutron scattering of orthoenstatite Mg{sub 2}Si{sub 2}O{sub 6}

Journal Article Choudhury, N ; Ghose, S ; Chowdhury, C P ; ... - Physical Review, B: Condensed Matter

Enstatite Mg{sub 2}Si{sub 2}O{sub 6} is an important rock-forming silicate of the pyroxene group. It exists in several polymorphs, the structures of which are characterized by double [MgO{sub 6}] octahedral bands and single silicate chains. This paper reports lattice-dynamical rigid-ion model calculations and polarized Raman and inelastic-neutron-scattering measurements of orthoenstatite Mg{sub 2}Si{sub 2}O{sub 6}, which is orthorhombic (Pbca) with 80 atoms in the unit cell. The calculated elastic constants, phonon frequencies, density of states, and specific heat are in good agreement with the experimental data. The optical-phonon branches along the {Sigma} and {Delta} directions are relatively flat without significant dispersion,more »« less
DOI: 10.1103/PhysRevB.58.756

Similar Records