Model electrodes with defined mesoscopic structure

Model electrodes with defined mesoscopic structure were either generated by adsorption of surfactant stabilized metal clusters from colloidal solution on a support of gold or by electrochemical deposition of platinum on gold substrates. Both types of model electrodes were characterized by STM (scanning tunnelling microscopy), cyclic voltammetry and electrooxidation of adsorbed CO. The supported colloidal Pt as well as the electrochemically deposited Pt revealed different reactivities regarding the CO monolayer electrooxidation as compared to a polycrystalline Pt bulk electrode. In addition, in-situ FTIR (Fourier transformed infrared) spectroscopy was applied to characterize CO adsorbed on electrochemically deposited Pt on gold. Combined with the structural information from STM it seems likely that the differences regarding the catalytic properties of the model electrodes are due to different coverages of the substrate with catalyst particles. Received: 24 June 1996 / Revised: 29 November 1996 / Accepted: 4 December 1996