Description :  

This project increases the participation of American students in research performed at internationally-recognized user facilities, leading to fundamental scientific understandings and an increase in the participation of domestic students in research at national user facilities. This purpose is accomplished through dissemination of our research findings in outreach programs at local high schools.  Synchrotron x-ray interrogations are performed at the J. Bennett Johnston Center for Advanced Microstructures and Devices (CAMD) in Baton Rouge, Louisiana. The scientific objective of this program is to explore the connections among local bonding, lattice crystallography, microstructure and the science of nanoscale and atomic-scale materials engineering in complex metal hydrides. 

This project contains two phases. In phase one, researchers study the local bonding environment of the dopant species in complex metal hydrides using x-ray absorption fine structure (XAFS). Using SAVS, we provide crystallographic information, such as the local bond length between dopant and host atoms and the coordination number for dopant atoms.  This information is much needed by the hydrogen storage research community because currently a trial-and-error approach is taken regarding to dopant selection and stoichiometry.  Coupled with existing information regarding kinetics of hydrogen desorption, knowledge of the atomic-scale interactions between the dopant atoms and host lattice aid in the broader understanding of the mechanism for improved hydrogen desorption.

In phase two, catalysts and dopants are the key components to engineer reactions. We seek to understand the preferred arrangement taken by these materials during mechanical milling.  The thermodynamic driving force for site stability competes with slow solid state diffusion kinetics.  The researchers explore means for preparation of nanostructure milling precursors.  New nanocomposite oxides and salts will be synthesized in nanocapsules produced via layer-by-layer self-assembly, the method pioneered by the project PIs.  After mechanical milling with commercial metal hydrides, these materials are characterized using XAFS and small angle x-ray scattering (SAXS).  This program uses synergism of two cutting edge approaches, i.e., nanoassembly and synchrotron characterization.Improved understanding of dopant local structure in complex metal hydrides is applied to the development of new methods for dopant addition and novel dopant chemistries. 

Broader impacts of the proposed work capitalize on an existing collaboration of PI’s between Grambling State University (GSU) and Louisiana Tech University (Tech).  Currently, students from GSU and Tech perform characterization and lithography research at three beamlines located at CAMD (two of the three are owned by Tech’s Institute for Micromanufacturing [IfM]). This project expands the participation of undergraduate and graduate students working at the synchrotron x-ray source at CAMD to area high school students—thus establishing a strong link between students and educators in Northern Louisiana and the state-of-the art user facility in Southern Louisiana.  Two graduate students (Tech) and six undergraduate students (three from GSU, three from Tech) participate in our research programs.  This research program is positioned to expose underrepresented student groups to research at national laboratories.

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Principal Investigator:  Dobbins, Tabbetha  --  Physics

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Collaborators:  Yuri Lvov and Roland Tittsworth

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Funding Agencies:  National Science Foundation

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Amount Awarded:  $183,643

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Start Period:  08/15/2005

End Period:  07/31/2007