Abstract
Nano-structured LaNi5 hydrogen storage materials prepared by ball-milling is analysed using differential scanning calorimetry (DSC) and x-ray photoelectron spectroscopy (XPS). DSC results indicate a partial elimination of defects at 500 °C in a more efficient way for the short-time ball-milled powders compared to the long-time ball-milled ones. XPS results show almost no change in the core-level electronic structure for La and Ni of LaNi5 in the bulk and the nano-structured forms, but gives an indication that the self-restoring mechanism of the active surface observed in the bulk sample (Siegmann et al. Phys. Rev. Lett. 40, 972) may not be occurring in the nano-powders. Results from the X-ray diffraction and the local structural studies together with the above observations suggest that the reduced unit-cell volume and the enhanced atomic disorder in the nano-structured LaNi5 cause a larger energy barrier for the hydrogen sorption reactions of the long-time ball-milled samples.
Lingua originale | English |
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pagine (da-a) | 7914-7919 |
Numero di pagine | 6 |
Rivista | International Journal of Hydrogen Energy |
Volume | 36 |
Stato di pubblicazione | Published - 2011 |
All Science Journal Classification (ASJC) codes
- ???subjectarea.asjc.2100.2105???
- ???subjectarea.asjc.2100.2103???
- ???subjectarea.asjc.3100.3104???
- ???subjectarea.asjc.2100.2102???