LAUSR

Abstract Co-Mo/Al2O3 used model and real-life catalysts from a diesel test are characterized by HR (S)TEM-EDX on ultra-thin sections to give a very complete description of MoS2 morphology, sulfidability and CoSx segregation. Image analysis is used to calculate the populations of different Mo sites. The low metal model catalyst contains only small 1-3 nm MoS2 structures. The real-life catalysts with higher metal content (dried Type II versus calcined Type I/II, H2S gas phase versus liquid phase sulfiding) are more complex and heterogeneous. Their MoS2 dispersion and Co segregation are related to the local compositions and start-up procedure. The median stack length and stacking from image analysis are much lower than the first visual impressions, dominated by short and large structures, respectively. The real-life catalysts are different from the model catalyst with respect to active phase characteristics and balance between brim and edge sites, which results in different catalyst activities and selectivities.