ON THE STUDY OF ADSORBED SPECIES AT PLATINUM FROM METHANOL, FORMIC-ACID AND REDUCED CARBON-DIOXIDE VIA INSITU FT-IR SPECTROSCOPY

Three different coordinated forms of CO adsorbed to the platinum surface were observed for methanol, formic acid and reduced carbon dioxide: linear-, bridge- and multi-bonded CO. Using a new experimental approach absolute absorption bands are observed for the adsorption of methanol and reduced carbon dioxide. Sample spectra are computed with respect to a reference spectrum which is taken before adsorption. In this way the presence of a COH adsorbate is demonstrated. The absolute band procedure must be applied to observe features exhibiting only a small dependence on potential, because in this case using the usual SNIFT-irS procedure (first adsorption and then collection of spectra at two potentials) the signals may cancel out when computing the difference spectra. Using Pt/Ru as a bifunctional catalyst for water splitting and CO/COH oxidation, surface poisoning during the oxidation of methanol is strongly diminished: current-potential relationships of technical interest are obtained.