Theoretical Model of CO Adsorption and Dissociation on Clean and K-doped beta-Mo2C Surfaces

PISTONESI, CAROLINA; PRONSATO, M. ESTELA; BUGYI. LAZLO; JUAN, A

JOURNAL OF PHYSICAL CHEMISTRY C

AMER CHEMICAL SOC

Lugar: Washington; Año: 2012 vol. 116 p. 24573 - 24581

1932-7447

We studied the effect of K on the adsorption and dissociation of CO on the B-Mo2C (001) surface by density functional theory calculations. Molecular CO adsorbs more strongly on Mo-terminated surfaces than on Cterminated ones. Adsorption is energetically more favorable in the presence of preadsorbed potassium. The CO molecule withdraws electron density from the surface, being more extended on the K-doped surface. The CO dissociation was also evaluated, and reaction pathways were modeled, revealing that the C-terminated surface is energetically less favorable than the Mo-terminated one. For both surfaces, the activation energy barrier for dissociation increases with the K content. C-O vibrational frequencies were also computed on K-modified surfaces.