Calculation of surface binding energy for hydrogen, oxygen, and carbon atoms on metallic surfaces

Abstract

The model of Polar Covalence developed by Sanderson was used to calculate binding energies at zero coverage for H, O, and C atoms adsorbed on metal surfaces. For 11 single crystal metals, the average absolute difference between the experimental and calculated binding energies of hydrogen atoms was 3–4 kcal mol . The model correctly predicts the weak binding of H on sp metals, e.g., Hg and Cd. Very similar agreement, 3–4 kcal mol , was obtained for O atoms on 8 single crystal metals. In the case of carbon atoms, the binding energy on Ru and Ni was calculated to be less than the atomization energy of graphite, in agreement with experiment. A similar effect on Pd surfaces is predicted. The calculated low binding energy, 40 kcal mol , of H atoms on top of Pd is supported by a combination of thermodynamic, quantum mechanical, spectroscopic and thermal desorption data. These calculations represent the first attempt to apply Sanderson's method to first, second, and third row transition metals and to surface thermodynamics.