Novel, Highly Conductive Pt/TiO2 Thin-Film Model Catalyst Electrodes: The Role of Metal-Support Interactions

Toward the aim of better understanding of metal-support interactions in oxide-supported Pt electrocatalysts, planar Pt/TiO2 model catalyst electrodes that combine high conductivity and direct Pt-TiO2 interactions are prepared and characterized. These consist of thin TiO2 films decorated with Pt nanoparticles on a glassy carbon substrate. TiO2 films are deposited by using a potential-induced sol-gel process and subsequently functionalized with Pt nanoparticles, by electrochemical Pt deposition, deposition of pre-formed Pt nanoparticles or by photo-assisted local reduction of Pt ions. Scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy are used for structural and electronic characterization of the model catalyst electrodes, as are cyclic voltammetry, electrooxidation of pre-adsorbed CO and O-2 reduction for evaluating their electrochemical/electrocatalytic properties. The impact of the Pt deposition method, of particle size effects and of metal-support interactions on the electrochemical properties and the catalytic activity/selectivity of these systems is discussed.