Zuckerman Faculty Scholar Baran Eren publishes paper in Physical Chemistry Chemical Physics Journal.
Baran’s laboratory focuses on understanding the atomic, chemical, and electronic structure of solid surfaces that are relevant to industrially and environmentally important fields like heterogeneous catalysis, electrochemistry, corrosion, and lubrication. Unlike classical surface science, the laboratory performs surface-sensitive spectroscopy and atomically resolved microscopy measurements in the presence of reactant gases or liquids, while avoiding significant sacrifices in terms of measurement resolution and accuracy.
Methanol is a promising chemical for the safe and efficient storage of hydrogen, where methanol conversion reactions can generate a hydrogen-containing gas mixture. Understanding the chemical state of the catalyst over which these reactions occur and the interplay with the adsorbed species present is key to the design of improved catalysts and process conditions. Here we study polycrystalline Cu foils using ambient pressure X-ray spectroscopies to reveal the Cu oxidation state and identify the adsorbed species during partial oxidation (CH3OH + O2), steam reforming (CH3OH + H2O), and autothermal reforming (CH3OH + O2 + H2O) of methanol at 200 °C surface temperature and in the mbar pressure range. We find that the Cu surface remains highly metallic throughout partial oxidation and steam reforming reactions, even for oxygen-rich conditions. However, for autothermal reforming the Cu surface shows significant oxidation towards Cu2O. We rationalise this behaviour on the basis of the shift in equilibrium of the CH3OH* + O* ⇌ CH3O* + OH* reaction step caused by the addition of H2O.