Thiolate protected nanoclusters with less than 100 atoms have recently become an intensively studied field, due to their outstanding properties resulting from non-bulk like structures and electronic configurations. The controlled design at atomic scale, including the number of atoms, but also metal composition or ligand functionalization, enables a broad field of applications. Monodisperse clusters with resolved structures constitute well-suited active phases for catalytic studies. Therefore, the present Master Thesis is focused on the design and synthesis of novel thiolate protected Co- and Co/Au-nanoclusters, as well as on the characterization of their properties, especially catalytic application. Cox(SR)m clusters in the size range of 2 nm were successfully synthesized for the first time, expanding the variety of thiolate protected metal clusters. These clusters have specific structure elements like a core in metallic state, which was determined by XPS, XAFS and EELS,and characteristic staple motifs, which were revealed by MALDI and Raman. Furthermore, cobalt doped thiolate protected gold nanoclusters were synthesized by two different approaches. Preliminary information on cluster composition (CoAu24(SR)18) was obtained by MALDI. The number of dopant atoms and their exact location is debated and may vary between the cluster core and staples, as based on the S K-edge XAFS, UV/Vis and DFT calculations. The synthesized clusters were supported on CeO2 by impregnation and the exact composition was determined by GIXRF. The stability and catalytic activity were tested in CO oxidation as model reaction. The prepared catalysts were pretreated and the removal of ligands was followed by XAFS. Supported Cox(SR)m did not show any activity but for the Co/Au catalyst in-situ DRIFTS-MS revealed a strong impact of cobalt doping on the reaction behavior, lowering the reaction onset temperature by 50 C, as compared to a pure Au25-CeO2 catalyst.