(600j) The Characterization of Micro-Structure of Cobalt on Gamma-Al2O3 for FTS:Effects of Pretreatment on Ru-Co/ Al2O3
The production of synthetic fuel by FTS has been received considerable interest due to the lower sulfur and aromatics. The activity and selectivity of supported cobalt catalysts depend on several factors such as particle size, nature of the support, the presence of the promoters, preparation methods including pretreatment conditions. In order to enhance the reducibility, noble metal promoters are introduced. Many researchers focus on the role and the actual structure of the termed alloy catalysts and bimetallic, although the role and the surface composition is still debating with uncertain. The noble metals have been suggested to influence catalyst performance in a number of different ways. They may act to promote hydrogen spillover and the activity by preventing the buildup of carbonaceous deposited.The objective of this work is to study the effect of calcination atmosphere with usage of the direct reduction on the cobalt over the structural support such as granule type γ-Al2O3.This work also investigates the impact on the microstructure by introducing ruthenium with different slurry impregnation method. To neglect the consideration of the term as the alloy and bimetallic catalyst, the relative higher weight ratio of Ru to total Co was fixed to 2/10. The effect of promoter was studied with the help of TPR, TEM, XPS and XRD analysis.Through the characterization and activity test of catalysts, The Air calcined catalysts has strong interaction with the support, which induced metallic phases related to fcc phases. In contrast, the catalysts calcined in hydrogen atmosphere having weak interaction with hcp structure showed uniform distribution of active species on the support. These phenomena are more clearly in the Ru promoted catalyst, which was affected by spillover and retained the cobalt cluster sizes. It was also observed that the hydrogen calcined catalyst shows the marginal effect on CO conversion and definitely makes the shift to middle distillation ranges by the presence of hcp structure of metal.