Electromodulated infrared spectroscopy of methanol electrooxidation on electrodispersed platinum electrodes: Enhancement of reactive intermediates

Abstract

EMIRS spectra of the surface species resulting from methanol electrosorption on electrodispersed Pt were obtained by working under a wide range of experimental conditions, i.e. electrode roughness factor, methanol concentration and mean modulation potential. The intensity of the absorption band related to linearly adsorbed CO-species, CO_L, at ca. 2030–2080 cm⁻¹ decreases on increasing the electrode roughness factor, a fact which is interpreted as a decrease in the CO adsorbate poisoning effect on electrodispersed Pt surfaces. As a consequence, under well-defined conditions, several bands are observed which might be assigned to adsorbed intermediates and reactive species. EMIRS also reveals a competition between CO_B and CO_L at high surface coverages. Spectral data for methanol electrooxidation on electrodispersed electrodes correlate well with the expected structure of this type of electrode.