Effect of Hydrogen in Adsorption and Direct Dissociation of CO on Fe (100) Surface: A DFT Study

SEBASTIAN AMAYA-RONCANCIO; DANIEL LINARES; HELIO A. DUARTE; GERMAN LENER; KARIM SAPAG

American Journal of Analytic

Scientific Research

Año: 2015 vol. 6 p. 38 - 46

2156-8251

Density functional theory was employed to investigate the effect of the hydrogen in the adsorption and direct dissociation of CO on Fe (100) surface. The preadsorption of hydrogen with coverages of 0, 1/3 and 2/3 monolayer (ML) was used in the present investigation. In the case of 1/3 ML of hydrogen, two configurations of adsorption were studied. The presence of hydrogen shows a major transference of electronic density from Fe surface to CO adsorbed, increasing the adsorption energy of CO from 2.00 eV in clean surface, to 2.76 eV in 2/3 ML of hydrogen.Furthermore, the activation barrier for direct dissociation of CO was 1.13eV and the recombination energy 2.28eV in clean Fe(100) surface.In the same way, the activation barrier for CO in presence of H coadsorbed was slightly affected presenting values of 1.06eV and 1.16 eV to 1/3 ML configurations and 0.98 eV to 2/3 ML of H. Finally, the recombination energy decrease to 1.63 eV and 1.49 eV for 1/3 ML configurations and to 1.23 eV for 2/3 ML of H coadsorbed. These results indicate that the CO adsorption and dissociation is favored in the presence of hydrogenated surfaces.