Methanol electro-oxidation at PtxRu(1-x)Oy electrodes -: An in situ FTIR study

In this work we investigated the nature of the intermediates adsorbed during the electrooxidation of methanol on PtxRu((1-x))O-y electrodes, where 0.5 < x < 0.9, prepared by the decomposition of polymeric precursors. Thin layer electrodes with different compositions were prepared directly on a gold substrate by thermal decomposition of ethylene glycol - citric acid solutions containing the precursor salts at 400 degrees C. In situ IR reflectance spectra were obtained using the SPAIRS (single potential alteration infrared reflectance spectroscopy) and SNIFTIRS (subtractively normalized interfacial Fourier transform IR reflectance spectroscopy) techniques. For all the investigated compositions, the SNIFTIRS and SPAIRS spectra displayed three main bands, which were attributed to CO species in the linear (COL) and bridged (COB) forms adsorbed over Pt and linearly adsorbed over Ru. Formation of CO2 carbonyl species was also detected. The spectra features were analyzed in terms of the applied potential and they were compared with those reported for Pt-Ru electrodes prepared by other methods.