View article

Model platinum catalysts have been designed to study the platinum−solvent interface in situ using attenuated total reflection (ATR) infrared spectroscopy. Pt and Pt/Al₂O₃ thin films were evaporated on a Ge internal reflection element (IRE) and characterized by XRD, XPS, AFM, STM, and IR spectroscopy. Changes within the adsorbate layer of the Pt catalyst during cleaning with O₂ and H₂ were followed. After cleaning, the catalyst surface was probed by CO adsorption from CH₂Cl₂. For the Pt/Al₂O₃ film the spectrum of adsorbed CO showed a band at 2000 cm^-1, which is typical for Pt/Al₂O₃ catalysts. The stretching vibration of linearly bonded CO exhibited a coverage-dependent frequency shift due to vibrational coupling, thus showing the existence of large clean domains on the reactive catalyst surface even in the presence of an organic solvent. CO adsorption from CH₂Cl₂ was slow before the cleaning process …