Keywords and Phrases
Alkali Metal; Energy; Hydrogen; Magnesium Borohydride; Sodium Aluminum Hydride; Transitional Metal
"Hydrogen serves as a promising new energy source having no pollution and abundant on earth. However the most difficult problem of applying hydrogen is to store it effectively and safely, which is smartly resolved by attempting to keep hydrogen in some metal hydrides to reach a high hydrogen density in a safe way. There are several promising metal hydrides, the thermodynamic and chemical properties of which are to be investigated in this dissertation.
Sodium alanate (NaAlH4) is one of the promising metal hydrides with high hydrogen storage capacity around 7.4 wt. % and relatively low decomposition temperature of around 100 ⁰C with proper catalyst. Sodium hydride is a product of the decomposition of NaAlH4 that may affect the dynamics of NaAlH4. The two materials with oxygen contamination such as OH- may influence the kinetics of the dehydriding/rehydriding processes. Thus the solid solubility of OH- groups (NaOH) in NaAlH5 and NaH is studied theoretically by DFT calculations.
Magnesium boride [Mg(BH4)2] is has higher hydrogen capacity about 14.9 wt. % and the decomposition temperature of around 250 ⁰C. However one flaw restraining its application is that some polyboron compounds like MgB12H12 preventing from further release of hydrogen. Adding some transition metals that form magnesium transition metal ternary borohydride MgaTMb(BH4)c] may simply the decomposition process to release hydrogen with ternary borides (MgaTMbBc). The search for the probable ternary borides and the corresponding pseudo phase diagrams as well as the decomposition thermodynamics are performed using DFT calculations and GCLP method to present some possible candidates"--Abstract, page iv.
Majzoub, Eric H.
Medvedeva, Julia E.
Hor, Yew San
Fraundorf, Phillip B.
Holmes, Stephen M.
Ph. D. in Physics
Missouri University of Science and Technology
Journal article titles appearing in thesis/dissertation
- A study of the heat and pressure induced S105 phase in NaAlH4
- Effects of NaOH in solid NaH: Solution/segregation phase transition and diffusion acceleration
- Density functional theory of MH-MOH solid solubility (M= alkali) and experiments in NaH-NaOH
xv, 157 pages
© 2016 Gang Wang, All rights reserved.
Dissertation - Open Access
Library of Congress Subject Headings
Hydrogen -- Storage
Electronic OCLC #
Wang, Gang, "DFT investigations of hydrogen storage materials" (2016). Doctoral Dissertations. 2520.