Structural and catalytic properties of supported Ni-Ir alloy catalysts for H2 generation via hydrous hydrazine decomposition

Lei He, Yanqiang Huang, Xiao Yan Liu, Lin Li, Aiqin Wang, Xiaodong Wang, Chung Yuan Mou, Tao Zhang

Research output: Contribution to journalArticlepeer-review

99 Citations (Scopus)

Abstract

Iridium modified Ni/Al2O3 catalysts were prepared using Ni-Al hydrotalcite as precursor and tested in the selective decomposition of hydrous hydrazine for H2 generation. Compared to Ni/Al2O3, NiIrx/Al2O3 catalysts exhibited an increase of the reaction rate up to 6-fold and the H2 selectivity from 93% to above 99%. The XRD and EXAFS analysis confirmed that Ir and Ni were present in the form of Ni-Ir alloy; and the H2 differential heat of adsorption is appreciably lowered with increasing the amount of Ir in Ni-Ir alloy. High-temperature reduction, e.g. 700°C, induced the migration of Ir atoms into the Ni bulk and produced a Ni-skin surface. This structural modification is associated with a strongly decrease of activity and selectivity. EXAFS measurements were also performed on different noble metals (NM, Ir, Pt, and Au) modified Ni/Al2O3 catalysts in order to verify the extent of NM-Ni bimetallic bond formation, which was found to correlate with the catalytic performance.

Original languageEnglish
Pages (from-to)779-788
Number of pages10
JournalApplied Catalysis B: Environmental
Volume147
DOIs
Publication statusPublished - Apr 5 2014
Externally publishedYes

Keywords

  • EXAFS
  • Hydrazine
  • Hydrogen storage
  • Microcalorimeter
  • Nickel-iridium alloy

ASJC Scopus subject areas

  • Catalysis
  • Environmental Science(all)
  • Process Chemistry and Technology

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