| AVS 55th International Symposium & Exhibition | |
| Surface Science | Thursday Sessions |
| Session SS2+NC-ThM |
| Session: | Catalysis on Nanoclusters |
| Presenter: | J. Kibsgaard, University of Aarhus, Denmark |
| Authors: | J. Kibsgaard, University of Aarhus, Denmark J.V. Lauritsen, University of Aarhus, Denmark S. Helveg, Haldor Topsoe A/S, Denmark H. Topsoe, Haldor Topsoe A/S, Denmark B.S. Clausen, Haldor Topsoe A/S, Denmark F. Besenbacher, University of Aarhus, Denmark |
| Correspondent: | Click to Email |
Within the area of nanomaterials it is well know that “small is different”, which implies that nanostructures may have new functional properties. Properties like conductivity, color, reactivity, magnetism, and melting point may thus be entirely different for the nanomaterial compared to the same properties for materials with macroscopic dimensions. The dimension of a material is therefore an important parameter to consider in the development of new nanomaterials. Not least in catalysis where the active materials today is confined to a limited number of metals, tuning the size of the catalytic particles may help in the development of new and better catalysts. The MoS2-based desulfurization catalyst constitutes one of the most important environmental catalysts as it removes sulfur from fossil fuels. Without this removal, the sulfur would cause massive acid rain problems such as forest decline. The recent focus on environmental problems and a stricter legislation concerning the sulfur content in fossil fuels have generated great interest in understanding and improving the desulfurization catalyst. We have used atom-resolved Scanning Tunneling Microscopy (STM) to follow the structural progression of triangular MoS2 nanoclusters as a function of their size, and analyse how the equilibrium structures are altered when the cluster size is reduced. A comprehensive analysis of the size distribution reveals that certain “magic” clusters are favored. The analysis reveals that a rearrangement of the sulfur atoms terminating the cluster edges influences the stability and that the requirement to optimize the sulfur excess relative to molybdenum drives a striking reconstruction of the cluster edge.