The Adsorption and Decomposition of Formic Acid on Cu{100} and Cu{100}Pt Surfaces using Temperature Programmed Reaction Spectroscopy Hamid M. Younis 1* and Ehab Alshamaileh 2 1 Department of Chemistry, Sciences Faculty, Sirte University, Sirte-Libya; hamid.younis@gmail.com 2 Department of Chemistry, University of Jordan, Amman, Jordan 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-difraction (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 efect on the formate intermediate. The peak temperature (T p ) for the CO 2 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 desta- bilisation 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 1. Introduction he adsorption and decomposition of formic acid at copper surfaces has been intensively studied over the years 1 . his is partly because of the key role that formate is believed to play in methanol synthesis and partly because it is an ideal model system. As a result of the attention it has received, the chemistry of the system is well understood. Upon adsorption at 300 K the formic acid dissociates to produce a bidentate formate intermediate, which bonds to adjacent sites on the copper surface through the two oxygen atoms. (Figure 1). 1.1 heory of Temperature Programmed Desorption (TPD) TPD as a surface analysis technique was introduced 2 in 1948. Since adsorption on clean metal surfaces is generally a non-activated process, the desorption activa- tion energy is then approximately equal to the diferential heat of adsorption 3 . his implies that TPD is a method of measuring the bond energy in adsorption. In addition, the reaction order can be deduced by comparing the peak shapes of TPD spectra. Compared to other surface techniques, TPD is con- sidered a straightforward and easy to interpret method. Apart from some experimental parameters such as the heating rate β, a typical TPD spectrum provides the des- orption peak maximum temperature, T p and a distinct trace shape that give information about the order of the desorption process. Several methods of analysis of TPD spectra have been described in the literature where the most convenient one is the Redhead method since it pro- vides fairly accurate results and small computation time 4 . Indian Journal of Science and Technology, Vol 7(12), 1916–1924, December 2014 ISSN (Print) : 0974-6846 ISSN (Online) : 0974-5645 *Author for correspondence