MODEL ELECTRODES WITH DEFINED MESOSCOPIC STRUCTURE

Model electrodes with defined mesoscopic structure were either generat ed by adsorption of surfactant stabilized metal clusters from colloida l solution on a support of gold or by electrochemical deposition of pl atinum on gold substrates. Both types of model electrodes were charact erized by STM (scanning tunnelling microscopy), cyclic voltammetry and electrooxidation of adsorbed CO. The supported colloidal Pt as well a s the electrochemically deposited Pt revealed different reactivities r egarding the CO monolayer electrooxidation as compared to a polycrysta lline Pt bulk electrode. Tn addition, in-situ FTIR (Fourier transforme d infrared) spectroscopy was applied to characterize CO adsorbed on el ectrochemically deposited Pt on gold. Combined with the structural inf ormation from STM it seems likely that the differences regarding the c atalytic properties of the model electrodes are due to different cover ages of the substrate with catalyst particles.