In Situ Diffraction of Fischer-Tropsch Catalysts: Cobalt Reduction and Carbide Formation

This publication highlights the effect of CO treatments on both calcined and reduced catalysts by using novel insitu techniques to track particle transformations, which are so vital to catalyst performance and activity. Cobalt carbide formation has been shown to occur readily with CO treatments on metallic cobalt particles, and in this study we have used insitu XRD and temperature-programmed reduction (TPR) techniques to track the evolution of the carbide. We were able to show a dependence on CO partial pressures and the formation of a single hexagonal phase of cobalt as a result of the carbide step. The stability of cobalt carbide was studied and its reduction in hydrogen to cobalt metal was observed. CO was also used as the reducing gas and by using TPR and insitu XRD we were able to demonstrate the reduction of cobalt oxide (Co3O4) to cobalt carbide (Co2C) via both oxide (CoO) and metal (Co) intermediates.