Ammonia decomposition over Ru and Ni catalysts supported on fumed SiO 2, MCM-41, and SBA-15

Xiu Kai Li, Wei Jie Ji*, Jing Zhao, Shui Ju Wang, Chak Tong AU

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

198 Citations (Scopus)

Abstract

The effects of using fumed SiO2, MCM-41, and SBA-15 as supports for Ru and Ni catalysts on ammonia decomposition were investigated. It was found that the supported catalysts on these siliceous materials are more active than those supported on ordinary silica. In general, the supported Ru catalysts are more active than the Ni catalysts, and MCM-41 is the best support material for Ru and Ni. Significant enhancement in activity was observed when the supported Ru catalysts were modified by KOH, but such effect was minimal in the cases of supported Ni catalysts. The results of N2 adsorption and transmission electron microscopy studies revealed that the Ni particles of Ni/MCM-41(TIE) prepared by template-ion exchange (TIE) method are largely located inside the pores of MCM-41. Compared with the Ni/MCM-41(IMP) catalyst prepared by impregnation method, the Ni/MCM-41(TIE) catalyst exhibited appropriate Ni dispersion and weaker Ni/support interaction, and consequently higher catalytic activity. In terms of the remarkable changes in turnover frequency (TOF) with Ni dispersion on different catalysts, it was demonstrated that NH3 decomposition over Ni is significantly structure sensitive. Some unique metal clusters similar to B5 active sites should be responsible for the catalytic activities. Preparation methodology has a substantial influence on metal dispersion. For the supported Ni catalysts prepared by the TIE method, the generated metal particles are very small and the constitution of unique active sites becomes unfavorable, which accounts for the apparently lower TOF values.

Original languageEnglish
Pages (from-to)181-189
Number of pages9
JournalJournal of Catalysis
Volume236
Issue number2
DOIs
Publication statusPublished - 10 Dec 2005

Scopus Subject Areas

  • Catalysis
  • Physical and Theoretical Chemistry

User-Defined Keywords

  • Ammonia decomposition
  • Nickel catalyst
  • Ruthenium catalyst
  • Siliceous materials

Fingerprint

Dive into the research topics of 'Ammonia decomposition over Ru and Ni catalysts supported on fumed SiO <sub>2</sub>, MCM-41, and SBA-15'. Together they form a unique fingerprint.

Cite this