CO2/CH4 reforming over Ni-La2O3/5A: An investigation on carbon deposition and reaction steps

J. Z. Luo, Z. L. Yu, C. F. Ng, Chak Tong AU*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

156 Citations (Scopus)

Abstract

CO2/CH4 reforming over Ni-La2O3/5A was studied using XRD, in situ thermal gravimeter (TG), pulse experiments, chemical trapping, transmission electron microscopy (TEM), and electron paramagnetic resonance. The small size (ca. 9 nm) Ni0 crystallites formed in H2 reduction remained unsintered during 48 hr of on-stream reaction at 800°C because of the formation of perovskite-like La2NiO4 phase in Ni-La2O3/5A. The main cause of the deactivation of Ni-La2O3/5A was the accumulation of carbon in the active sites. The contribution of CO2 towards deposited carbon was greater than that of CH4 at higher temperatures. Based on the facts that the TG profiles and TEM images of carbon formed in CO and CO2/CH4 atmospheres were very similar, the carbon deposition was mainly via CO disproportionation. Due to the mutual activation of CO2 and CH4, the existence of H (or O) species on the catalyst surface could promote the activation of CO2 (or CH4) significantly. A reaction pathway for the reforming reaction was proposed and suggested that CHxO (x = 1 or 2) decomposition is a rate-determining step.

Original languageEnglish
Pages (from-to)198-210
Number of pages13
JournalJournal of Catalysis
Volume194
Issue number2
DOIs
Publication statusPublished - 10 Sep 2000

Scopus Subject Areas

  • Catalysis
  • Physical and Theoretical Chemistry

User-Defined Keywords

  • Carbon deposition
  • Chemical trapping
  • CO/CH reforming
  • Isotope effect
  • Ni-LaO/5A
  • Nickel catalyst
  • Reaction mechanism

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