Description :  

A strong research program in the area of synchrotron x-ray characterization of low Z materials is the main objective of this project.  Complex metal hydrides are capable of incorporating hydrogen into their lattice.  Studies show that reduced desorption temperatures may be attributed to transition metal and rare earth dopants.  The lattice structure of such dopants has not been fully described.  Researchers study the local bonding environment of dopant atoms using x-ray absorption fine structure (XAFS). Coupled with kinetic studies for hydrogen desorption, this project broadens understanding of mechanisms for hydrogen desorption by determining the structure of dopant atoms using XAFS in order to engineer hydrogen desorption kinetics. An interdisciplinary approach to this problem is employed using x-ray characterization and layer-by-layer nanosynthesis.  This work extends past synchrotron x-ray research performed by the PI (Dr. Tabbetha A. Dobbins).

There are two main phases to this project.

Phase I: Ti-doped NaAlH₄ powders prepared at the Institute for Micromanufacturing via mechanical milling are characterized using XAFS at the Center for Advanced Microstructures and Devices (CAMD). Additionally, analysis of those dopants, which are not highly influential in improving hydrogen desorption kinetics, provide useful information.  Several dopants are examined.

Phase II: Dopant atoms seek free energy mimina locale.  During mechanical milling, the thermodynamic driving force for site stability competes with solid state diffusion kinetics.  To reduce the diffusion distances, we prepare nanostructure precursors via layer-by-layer self-assembly, the method pioneered by the project’s other investigator.

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Principal Investigator:  Dobbins, Tabbetha  --  Physics

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Collaborators:  

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Funding Agencies:  Board of Regents

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Amount Awarded:  $91,111

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Start Period:  06/01/2005

End Period:  06/30/2008