Spontaneous deposition of Ru on Pt (100): Morphological and electrochemical studies. Preliminary results of ethanol oxidation at Pt(100)/Ru

Abstract

In the present work ruthenium was deposited in submonolayer amounts on Pt(100) by spontaneous deposition at several deposition times. The Pt (100)/Ru surfaces were analyzed using ex-situ STM to image the deposits characteristic of ruthenium on Pt (100). It was observed the formation of ruthenium islands with diameters between 1.0 and 4.5 nm with bi-atomic thickness in the center of the islands. A homogeneous distribution of the ruthenium islands on the platinum terraces was found, with no preferential deposition on steps or surface defect sites. The ruthenium coverage degree had been calculated by the decrease of charge of the hydrogen adsorption-desorption peaks in the cyclic voltammograms of the Pt(100)/Ru electrodes. The Pt(100)/Ru electrodes with a ruthenium coverage degree of ca. 0.3 showed a high activity for the ethanol electrooxidation. The electrochemical experimental results support strongly the bifunctional mechanism for the enhanced ethanol oxidation.