Sato Toyoto, Daemen Luke L, Cheng Yongqiang, Ramirez-Cuesta Anibal J, Ikeda Kazutaka, Aoki Takuma, Otomo Toshiya, Orimo Shin-Ichi
Institute for Materials Research, Tohoku University, Sendai, Miyagi, 980-8577, Japan.
Neutron Scattering Division, Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA.
Chemphyschem. 2019 May 16;20(10):1392-1397. doi: 10.1002/cphc.201801082. Epub 2019 Jan 23.
The hydrogen-release reaction of a complex transition metal hydride, LaMg NiH , composed of La , 2×Mg , [NiH ] and 3×H , was studied by thermal analyses, powder X-ray, and neutron diffraction and inelastic neutron scattering. Upon heating, LaMg NiH released hydrogen at approximately 567 K and decomposed into LaH and Mg Ni. Before the reaction, covalently bound hydrogen (H ° ) in [NiH ] exhibited a larger atomic displacement than H , although a weakening of the chemical bonds around [NiH ] and H was observed. These results indicate the precursor phenomenon of a hydrogen-release reaction, wherein there is a large atomic displacement of H ° that induces the hydrogen-release reaction rather than H . As an isothermal reaction, LaMg NiH formed LaMg NiH at 503 K in vacuum for 48 h, and LaMg NiH reacted with hydrogen to reform LaMg NiH at 473 K under 1 MPa of H gas pressure for 10 h. These results revealed that LaMg NiH exhibited partially reversible hydrogen-release and uptake reactions.
通过热分析、粉末X射线、中子衍射和非弹性中子散射研究了由La、2×Mg、[NiH]和3×H组成的复合过渡金属氢化物LaMgNiH的氢释放反应。加热时，LaMgNiH在约567 K释放氢并分解为LaH和MgNi。反应前，[NiH]中以共价键结合的氢（H°）比H表现出更大的原子位移，尽管观察到[NiH]和H周围的化学键有所减弱。这些结果表明了氢释放反应的前驱体现象，即H°有较大的原子位移引发了氢释放反应而非H。作为等温反应，LaMgNiH在503 K真空下48小时形成LaMgNiH，并且LaMgNiH在473 K、1 MPa氢气压力下10小时与氢反应重新形成LaMgNiH。这些结果表明LaMgNiH表现出部分可逆的氢释放和吸收反应。
