Ethanol Electrooxidation on Bi Submonolayers Deposited on a Pt Electrode

Bismuth submonolayers covering polycrystalline platinum-surface electrodes have been prepared with several degrees of Bi covering 0.34, 0.58, and 0.92 monolayers, respectively. These samples were used to investigate ethanol electrooxidation using cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy. Suppression of hydrogen adsorption was observed as the degree of Bi covering on the Pt surface increased. Ethanol electrooxidation increased 5.5-fold for Pt/Bi-0.34ML compared with Pt using constant potential polarization at 0.5 V. Electrochemical impedance experiments showed that Pt/Bi-0.34ML electrodes exhibited the lowest charge transfer resistance, which is in agreement with voltammetric and chronoamperometric measurements.