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| Title: | CHARACTERIZATION OF COMPLEX METAL HYDRIDES BY HIGH-RESOLUTION SOLID STATE NMR SPECTROSCOPY | |
| DOI No: | 10.1142/9789812838025_0018 | |
| Source: | MATERIALS ISSUES IN A HYDROGEN ECONOMY (pp 192-202) | |
| Author(s): | ROBERT C. BOWMAN, JR.
Jet Propulsion Laboratory, Mail Stop 79-24, California Institute of Technology, Pasadena, CA 91109-8099, USA JOSEPH W. REITER Jet Propulsion Laboratory, Mail Stop 79-24, California Institute of Technology, Pasadena, CA 91109-8099, USA SON-JONG HWANG Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA CHUL KIM Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA HOURIA KABBOUR Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA 91125, USA |
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| Abstract: | Solid state nuclear magnetic resonance (NMR) studies provide very detailed information on the complicated processes involving the formation of hydride phases and their transformations including reversibility and the roles of catalysts. Examples from recent investigations on complex metal hydrides illustrate how NMR can address and often resolve diverse issues on phase formation and decomposition processes. First, the behavior of Sc-doping on the phase compositions and reactivity of the sodium tetra- and hexa-alanates has been assessed from the 45Sc, 27Al, and 23Na spectra following mechanical milling and hydrogen absorption/desorption treatments. Second, the formation and subsequent hydrogen desorption from several borohydrides was investigated using 11B MAS and CPMAS spectra that included clear evidence for the formation of highly stable intermediate "BnHn" species, mainly as MxB12H12 phases, in their decomposition products that severely impact their ability to reform the initial borohydride phases. Finally, NMR was used phase identification in the Li-Mg-Al-N-H system that could not be confirmed by x-ray diffraction or other methods. | |
| Full Text: | View full text in PDF format (214KB) | |
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