Catalysis Letters

, Volume 28, Issue 2–4, pp 291–299 | Cite as

Activation of Ni/A12O3 catalysts through modification of the Al2O3 support

  • Lars Peter Lindfors
  • Stefan Smeds
Article

Abstract

The effect of alumina pretreatment on the performance of alumina supported nickel catalysts was demonstrated in gas phase hydrogenation of toluene to methylcyclohexane. The state of the alumina was changed from pure γ to pure θ phase through various heat treatments in air. The catalysts were prepared from vapor phase by saturating the accessible binding sites on the pretreated alumina with the nickel precursor. The highest number of active sites for hydrogenation was observed for catalysts prepared on alumina having an incomplete phase transition and a θ/γ alumina phase ratio between 0.5 and 10. Results from temperature programmed desorption (TPD) studies revealed that a maximum in weakly chemisorbed hydrogen as well as in total amount of desorbed hydrogen was found for the same catalysts. By hydrogen chemisorption studies the total hydrogen uptake was found to correlate with the observed hydrogenation maximum. It is suggested that both the chemical and physical properties of the alumina influence the activity. An optimal metal-support interaction and structural defects on the alumina due to the phase transition can explain the observed maximum in the number of active sites and in hydrogen uptake.

Keywords

Ni/Al2O3 catalysts γ-θ-alumina hydrogenation activity/TOF TPD of hydrogen H2 chemisorption 

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Copyright information

© J.C. Baltzer AG, Science Publishers 1994

Authors and Affiliations

  • Lars Peter Lindfors
    • 1
  • Stefan Smeds
    • 2
  1. 1.Neste OyTechnology CentreBorgåFinland
  2. 2.Laboratory of Industrial ChemistryÅboFinland

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