Indian Journal of Science and Technology

Abstract

The structures formed by adsorbing thin-film platinum, formic acid and oxygen on Cu{100} single crystal are investigated by quantitative low-energy electron-diffraction (LEED) and Temperature Programmed Reaction Spectroscopy (TPRS). Symmetrized Automated Tensor LEED (SATLEED) calculations are used to determine the structure of the formed surface alloys and overlayers. TPRS was used to probe the surface reactivity of the systems studied while surface composition was obtained using Auger Electron spectroscopy (AES). The decomposition of a formate intermediate from a clean Cu{100} surface has been monitored through the use of TPD Spectroscopy. It has also been evidenced that platinum has a destabilising effect on the formate intermediate. The peak temperature (Tp ) for the CO2 desorption spectra from copper-platinum model surfaces, appear around 40 K lower than those from clean copper. This suggests a much less stable surface alloy compared to the clean surface. In activation energy terms, this destabilisation can be expressed as a 13% decrease in the energy required for the formate to decompose. It was also observed that desorption is much more rapid from the copper-platinum than from clean copper surfaces.

Keywords: Cu{100}, Cu{100}Pt, Formic Acid, TPRS