Creating the hydrogen absorption capability of CeNi5 through the addition of Al

Ryo Yamagishi, Takayuki Kojima, Satoshi Kameoka, Daisuke Okuyama, Taku J. Sato, Chikashi Nishimura, An Pang Tsai

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

The hydrogenation capacities of CeNi5−xAlx (x = 0, 0.75, 1.0, 1.25, 1.5 and 1.75) alloys were assessed. In contrast to LaNi5-based alloys, the addition of Al to CeNi5 enables hydrogen absorption by creating larger interstitial sites as the result of an expanded lattice. Structure analyses indicate that each of these alloys maintained a CeNi5 (CaCu5-type) structure in which Al atoms exclusively occupied Ni 3g sites. Among these specimens, CeNi4Al absorbed the greatest proportion of hydrogen atoms, decreasing its c/a ratio from 0.826 to 0.802 upon the formation of CeNi4AlH4.3. This drastic decrease in the c/a ratio is attributed to an anisotropic lattice expansion along the a-axis, as verified by in situ X-ray diffraction under H2. The enhanced hydrogen absorption of these alloys is thought to be associated with the preferential situation of hydrogen atoms at interstitial sites located at the centers of octagons as well as a charge transition of Ce ions upon hydrogenation. It is verified that CeNi4Al after hydrogenation shows high catalytic activity toward propyne hydrogenation: 100% conversion of propyne even at room temperature.

Original languageEnglish
Pages (from-to)21832-21840
Number of pages9
JournalInternational Journal of Hydrogen Energy
Volume42
Issue number34
DOIs
Publication statusPublished - 2017 Aug 24

Keywords

  • CeNiAl alloys
  • Hydrogen-storage materials
  • Hydrogenation of propyne
  • Intermetallic compounds
  • Site preference
  • Size effects

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Condensed Matter Physics
  • Energy Engineering and Power Technology

Fingerprint Dive into the research topics of 'Creating the hydrogen absorption capability of CeNi<sub>5</sub> through the addition of Al'. Together they form a unique fingerprint.

Cite this