Steam reforming of hydrocarbons from biomass-derived syngas over MgAl2O4-supported transition metals and bimetallic IrNi catalysts

Vanessa Lebarbier Dagle, Robert Dagle, Libor Kovarik, Arda Genc, Yang Gang Wang, Mark Bowden, Haiying Wan, Matthew Flake, Vassiliki Alexandra Glezakou, David L. King, Roger Rousseau

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27 Citations (Scopus)

Abstract

This study presents an investigation into the steam reforming of hydrocarbons from biomass gasifier-derived syngas over MgAl2O4-supported transition metals (Ni, Rh, Ir, Ru, Pt, and Pd) and novel bimetallic IrNi catalysts. Using a model syngas consisting of H2, CO, CO2, CH4, C2H4, and H2O, Ir and Rh catalysts were found to be the most stable catalysts (at 850°C, 1bar, 114,000h-1). When benzene and naphthalene are added to the feed (as a tar simulant) stability is affected by both tar concentration and type of tar. Catalytic deactivation, caused primarily by coking can be minimized by operating at a high reaction temperature (e.g., 850°C). In addition, promoting Ni catalyst with Ir significantly enhances stability. By using bimetallic formulations of Ir and Ni (0.5-5.0% Ir, 15%Ni), nickel sintering during the reaction is reduced. Surprisingly, IrNi catalysts also offer more stability than catalysts with Ir particles alone. In agreement with theoretical calculations, small Ir° clusters (~2-3 atoms) supported on large Ni° particles (≥5nm) present more resistance to coking than either small Ir° clusters or Ni° particles alone. Hence, superior stability of the bimetallic catalysts results from both resistance to coking and a decrease in nickel sintering. Minimal loss of activity of 12% for TOS=80h is demonstrated for a bimetallic catalyst with optimal concentrations of 2.5% Ir and 15% Ni. Both monometallic Ir and Ni catalysts suffer substantial loss of activity (i.e., ≥40% loss, TOS=80h) under comparable conditions.

Original languageEnglish
Pages (from-to)142-152
Number of pages11
JournalApplied Catalysis B: Environmental
Volume184
DOIs
Publication statusPublished - May 5 2016

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Keywords

  • Bimetallic catalyst
  • Biomass
  • Gasification
  • Ir
  • Ni
  • Noble metals
  • Rh
  • Steam reforming
  • Syngas
  • Tar

ASJC Scopus subject areas

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

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