Dynamics of ammonia borane using neutron scattering

被引:21
作者
Brown, Craig M. [1 ]
Jacques, Teresa L.
Hess, Nancy J.
Daemen, Luke L.
Mamontov, Eugene
Linehan, John C.
Stowe, Ashley C.
Autrey, Tom
机构
[1] Univ Maryland, Dept Mat Sci & Engn, College Pk, MD 20742 USA
[2] NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA
[3] Smith Coll, Dept Chem, Northampton, MA 01063 USA
[4] Pacific NW Natl Lab, Richland, WA 99352 USA
[5] Los Alamos Natl Lab, Manuel Lujan Jr Neutron Scattering Ctr, Los Alamos, NM 87545 USA
[6] Pacific NW Natl Lab, Fundamental Sci Div, Richland, WA 99352 USA
基金
美国国家科学基金会;
关键词
hydrogen storage; dynamics; neutron; quasielastic scattering; backscattering;
D O I
10.1016/j.physb.2006.05.063
中图分类号
O469 [凝聚态物理学];
学科分类号
070205 ;
摘要
We have used both the backscattering (HFBS) and time-of-flight (DCS) neutron spectrometers to investigate proton dynamics in ammonia borane, a compound of intense interest as a model for 'chemical hydrogen storage' materials. Results indicate that the deposition of ammonia borane on a mesoporous silicate results in longer proton residence times and lower energy barriers for proton motion compared to bulk ammonia borane. The reduced activation energy for proton motions may partly explain the improved thermolysis and lowering the activation barrier for the loss of the first equivalent of H-2. In addition, the phonon density of states for neat ammonia borane compares well with other spectroscopic results, with the intense peak at 22meV assigned to the librational NH3 and BH3 modes, whereas ammonia borane on MCM-41 displays a broad, featureless spectrum indicating a poorly crystalline material. Published by Elsevier B.V.
引用
收藏
页码:266 / 268
页数:3
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