TY - JOUR
T1 - Hydrogen-Release Reaction of a Complex Transition Metal Hydride with Covalently Bound Hydrogen and Hydride Ions
AU - Sato, Toyoto
AU - Daemen, Luke L.
AU - Cheng, Yongqiang
AU - Ramirez-Cuesta, Anibal J.
AU - Ikeda, Kazutaka
AU - Aoki, Takuma
AU - Otomo, Toshiya
AU - Orimo, Shin ichi
N1 - Publisher Copyright:
© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
PY - 2019/5/16
Y1 - 2019/5/16
N2 - The hydrogen-release reaction of a complex transition metal hydride, LaMg 2 NiH 7 , composed of La 3+ , 2×Mg 2+ , [NiH 4 ] 4− and 3×H − , was studied by thermal analyses, powder X-ray, and neutron diffraction and inelastic neutron scattering. Upon heating, LaMg 2 NiH 7 released hydrogen at approximately 567 K and decomposed into LaH 2−3 and Mg 2 Ni. Before the reaction, covalently bound hydrogen (H c ° v. ) in [NiH 4 ] 4− exhibited a larger atomic displacement than H − , although a weakening of the chemical bonds around [NiH 4 ] 4− and H − was observed. These results indicate the precursor phenomenon of a hydrogen-release reaction, wherein there is a large atomic displacement of H c ° v. that induces the hydrogen-release reaction rather than H − . As an isothermal reaction, LaMg 2 NiH 7 formed LaMg 2 NiH 2.4 at 503 K in vacuum for 48 h, and LaMg 2 NiH 2.4 reacted with hydrogen to reform LaMg 2 NiH 7 at 473 K under 1 MPa of H 2 gas pressure for 10 h. These results revealed that LaMg 2 NiH 7 exhibited partially reversible hydrogen-release and uptake reactions.
AB - The hydrogen-release reaction of a complex transition metal hydride, LaMg 2 NiH 7 , composed of La 3+ , 2×Mg 2+ , [NiH 4 ] 4− and 3×H − , was studied by thermal analyses, powder X-ray, and neutron diffraction and inelastic neutron scattering. Upon heating, LaMg 2 NiH 7 released hydrogen at approximately 567 K and decomposed into LaH 2−3 and Mg 2 Ni. Before the reaction, covalently bound hydrogen (H c ° v. ) in [NiH 4 ] 4− exhibited a larger atomic displacement than H − , although a weakening of the chemical bonds around [NiH 4 ] 4− and H − was observed. These results indicate the precursor phenomenon of a hydrogen-release reaction, wherein there is a large atomic displacement of H c ° v. that induces the hydrogen-release reaction rather than H − . As an isothermal reaction, LaMg 2 NiH 7 formed LaMg 2 NiH 2.4 at 503 K in vacuum for 48 h, and LaMg 2 NiH 2.4 reacted with hydrogen to reform LaMg 2 NiH 7 at 473 K under 1 MPa of H 2 gas pressure for 10 h. These results revealed that LaMg 2 NiH 7 exhibited partially reversible hydrogen-release and uptake reactions.
KW - complex transition metal hydride
KW - crystal structure
KW - inelastic neutron scattering
KW - neutron diffraction
KW - vibration
UR - http://www.scopus.com/inward/record.url?scp=85060636033&partnerID=8YFLogxK
U2 - 10.1002/cphc.201801082
DO - 10.1002/cphc.201801082
M3 - Article
C2 - 30575253
AN - SCOPUS:85060636033
SN - 1439-4235
VL - 20
SP - 1392
EP - 1397
JO - ChemPhysChem
JF - ChemPhysChem
IS - 10
ER -