Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
54614 | Catalysis Today | 2013 | 6 Pages |
•Different activation procedures have been applied to support Co catalysts.•Cobalt phase evolution has been followed by in situ XRD and magnetic measurements.•Reduction degree and crystallographic orientation depend on particle size & support.•Carbidisation–decarbidisation leads to mainly hexagonal closed packed cobalt.
Fischer–Tropsch synthesis uses cobalt catalysts to convert syngas into linear hydrocarbons. Activation is the key step generating and impacting the active phase and more precisely the crystallographic structure of the metallic cobalt particles. This study investigates the selective crystallographic orientation of cobalt-supported catalysts and its impact on the degree of reduction. Three catalysts supported on alumina and silica with various particle sizes were prepared and characterized by ex situ techniques. They underwent two kinds of reduction processes carried out under different atmospheres. A carbidisation–decarbidisation cycle was also performed on reduced catalysts. The evolution of the active phase under reactive conditions was followed by in situ X-Ray Diffraction and magnetic measurements. The different reduction processes gave rise to the formation of metallic cobalt with mainly a face-centered cubic structure. The degree of reduction was also affected by the type of reduction process. Carbidisation–decarbidisation had no global impact on the reduction extent and allowed the formation of mainly hexagonal closed packed metallic cobalt.
Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (120 K)Download as PowerPoint slide