Graduation Year
2009
Document Type
Dissertation
Degree
Ph.D.
Degree Granting Department
Chemical Engineering
Major Professor
Venkat R. Bhethanabotla, Ph.D.
Co-Major Professor
Elias Stefanakos, Ph.D.
Committee Member
Yogi Goswami, Ph.D.
Committee Member
Vinay Gupta, Ph.D.
Committee Member
Lilia Woods, Ph.D.
Committee Member
Sesha Srinivasan, Ph.D.
Keywords
Density functional theory, lattice dynamics, thermodynamics, stability, mechano-chemical process, nanocatalyst doping
Abstract
Materials that are light weight, low cost and have high hydrogen storage capacity are essential for on-board vehicular applications. Some reversible complex hydrides are alanates and amides but they have lower capacity than the DOE target (6.0 wt %) for 2010. High capacity, light weight, reversibility and fast kinetics at lower temperature are the primary desirable aspects for any type of hydrogen storage material. Borohydride complexes as hydrogen storage materials have recently attracted great interest.
Understanding the above parameters for designing efficient complex borohydride materials requires modeling across different length and time scales. A direct method lattice dynamics approach using ab initio force constants is utilized to calculate the phonon dispersion curves. This allows us to establish stability of the crystal structure at finite temperatures. Density functional theory (DFT) is used to calculate electronic properties and the direct method lattice dynamics is used to calculate the finite temperature thermodynamic properties. These computational simulations are applied to understand the crystal structure, nature of bonding in the complex borohydrides and mechanistic studies on doping to improve the kinetics and reversibility, and to improve the hydrogen dynamics to lower the decomposition temperature.
A combined theoretical and experimental approach can better lead us to designing a suitable complex material for hydrogen storage. To understand the structural, bulk properties and the role of dopants and their synergistic effects on the dehydrogenation and/or reversible rehydrogenation characteristics, these complex hydrides are also studied experimentally in this work.
Scholar Commons Citation
Choudhury, Pabitra, "Theoretical and Experimental Study of Solid State Complex Borohydride Hydrogen Storage Materials" (2009). USF Tampa Graduate Theses and Dissertations.
https://digitalcommons.usf.edu/etd/1900
