Oxide mediated interaction of Os CO/ NCCH /at 3 11 3 photoelectrochemically oxidized surfaces of MoS : 2 an STM and XPS study

Metal carbonyl clusters and their interaction with substrates are important for catalytic applications. In this study we report on the analysis of MoS2surfaces interaction with Os3 CO.11 NCCH3.. These modified MoS2 surfaces are analyzed by scanning tunneling microscopy STM.and X-ray photoelectron spectroscopy XPS.. The STM analysis proves to be a very helpful technique to determine the presence, morphology, and size of cluster assemblies on the MoS2 surface. On the other hand, XPS gives spectroscopic information about the interactions of the cluster with the substrate. Both techniques give evidence on the presence of the Os cluster at imperfections on the MoS2 surface. The studies on the Os cluster interaction at photoelectrochemically oxidized MoS2give reasons to believe that at the MoS2imperfections an enhanced reactivity occurs. This is due to the presence of dangling bonds. These dangling bonds have oxides or other oxygen containing groups e.g., OH.that act as coordination sites for the clusters. In this way, we show a way of controlling the amount of surface modification by controlling the amount of imperfections on the MoS2 surface by photoelectrochemical oxidation. q1999 Elsevier Science B.V. All rights reserved.