(258f) Studies on Reduction Conditions to Generate Different Cobalt Species in Co/Gamma-Al2O3 for Catalytic Activity

Generation of active metallic species is an important aspect during reduction in metal supported catalysts. Metallic cobalt species are active catalysts in many reactions and particularly in Fischer-Tropsch synthesis. The present work describes the effect of reduction conditions to generate the different cobalt species in Co/γ-Al₂O₃. The effect of temperature and ramp during the reduction and GHSV of H₂ (concentration) were studied. The reduced catalysts were characterized by various physico-chemical techniques such as N₂ physisorption, XRD, TPR, TEM and XPS. Nonreducible Co-surface species are formed by thermodynamic driving force interacting with γ-Al₂O₃ supports and also it was confirmed that temperature ramp and GHSV significantly affect the species change of cobalt after reduction. These nonreducible Co species were different with metallic cobalt or Cobalt aluminate (CoAl₂O₄) by diverse analyzing and the formation of these showed a trend by changes of reduction condition. In conclusion, the results revealed that various Co species are generated with the different reduction conditions and this phenomenon will give helpful data to understand catalytic activity in Co/ γ-Al₂O₃ catalysts.