Reports: G5
46660-G5 Surface Science Investigation of MoS2 Nanoclusters Supported on TiO2 for a Fundamental Understanding of Hydrodesulfurization Catalysts
In the second year of this project we published one paper in Physical Review B on the interaction of H2S with the polar ZnO surfaces. This fundamental study showed that there is a large charge transfer at the interface between ZnO and ZnS and that a initial fast sulfidation of ZnO is followed by a very slow sulfur uptake after completion of the first monolayer. This paper completes our studies on the interaction of H2S with single crystal ZnO and we have turned to study the interaction of H2S with nanocrystalline ZnO. To this extend initial work has begun to grow nanowires by catalyst assisted molecular beam epitaxy. This work will form the basis of future grant applications.
The work on the formation of MoS2 clusters on TiO2 took a turn to study the effect of surface defects on TiO2 on the formation and structure of MoS2 clusters. In particular we are interested in the effect of step edges on cluster formation. To this end we pioneered a method to structure single crystal TiO2 substrates with defined step edge morphologies. Utilizing a grazing incident ion beam we were able to direct step edges along the direction of the ion beam and thus to prepare step edges with defined crystallographic orientations. This work is ready for publication in the near future. The thus patterned substrates are now investigated for the growth of MoS2 clusters.
