Carbon-supported hydrotreating catalysts: Morphology of MoS2, Co-MoS2 and Ni-MoS2 nanoclusters as observed by HAADF-STEM

PETR 2

Michael Brorson, mib@topsoe.dk, Anna Carlsson, abc@topsoe.dk, and Henrik Topsøe, het@topsoe.dk. Haldor Topsøe A/S, Nymøllevej 55, Lyngby, DK-2800, Denmark
The morphology of WS2 nanoclusters in carbon-supported model catalysts was recently investigated using High Angular Annular Dark-Field Scanning Transmission Electron Microscopy (HAADF-STEM).1 These studies are presently extended to promoted and unpromoted MoS2-based catalysts. Co-impregnation of (NH4)2[MoS4] and M'(acetate)2 (M'= Co, Ni) on high surface area graphitic carbon followed by treatment with 10% H2S in H2 gave rise to predominantly single S−Mo−S layer structures. The most common regular MoS2 shape was slightly truncated triangular. When promoter atoms were present, the typical shape was more truncated and the structures had rounded corners. Posttreatment of MoS2 with 100% H2 increased the extent of truncation, whereas posttreatment with 100% H2S led to non-regular multilayer structures. The results will be discussed in relation to the observed catalysis and the structures observed by Scanning Tunneling Microscopy (STM) of MoS2-based nanoclusters on Au(111) surfaces. (1) Carlsson, A.; Brorson, M.; Topsøe, H. J. Catal. 2004, 227, 530-536.