Hydrogen conduction in oxide materials

Quasielastic energy widths versus momentum transfer at 685 K and der

Quasielastic energy widths versus momentum transfer at 685 K and derived diffusion parameters. Inset shows a schematic of the proposed hopping mechanism for hydride diffusion along the a axis within the perovskite-type layer of LaSrCoO3H0.7
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Compounds which exhibit high hydrogen conduction have potential applications in devices such as fuel cells and hydrogen sensors

Compounds which exhibit high hydrogen conduction are currently of considerable interest due to potential applications in devices such as fuel cells and hydrogen sensors. Protonic conduction in perovskite-type oxides (e.g. SrCe0.95Yb0.05O3-d) has been extensively examined, while similar information on hydride conduction in oxides is lacking. Quasi-elastic neutron scattering (QENS) has provided quantitative information on hydride diffusion in the novel transition metal oxide hydride LaSrCoO3H0.7. Variable temperature, high resolution QENS data reveal the onset of hydride anion mobility above 675K via a jump process involving long-range diffusion of individual hydride anions. The site-to-site hopping distance is equal to the length of the a axis of the crystal unit cell, suggesting that diffusion occurs between vacancies in the hydride anion sublattice. Furthermore, diffusion coefficients have been used to obtain an estimate of the conductivity, which is significantly higher than has been observed in proton conducting materials.

CA Bridges (University of Liverpool), F Fern√°ndez-Alonso (ISIS), JP Goff, MJ Rosseinsky (University of Liverpool)

Research date: December 2006

Further Information

Prof MJ Rosseinsky, [m.j.rosseinsky@liverpool.ac.uk] CA Bridges et al., J. Am. Chem. Soc. 92 (2005) 5996

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