Proton abstraction ability of MgO: a DFT cluster model study of the role of surface geometry

BRANDA, MARÍA MARTA; BELELLI, PATRICIA GABRIELA; FERULLO, RICARDO MARIO; CASTELLANI, NORBERTO JORGE

CATALYSIS TODAY

Elsevier

Año: 2003 vol. 85 p. 153 - 165

0920-5861

Methanol and isocyanic acid adsorptions on a defectiveMgOsurface have been studied. Equilibrium geometries, adsorption energies, atomic and molecular charges and electronic densities were obtained using a density functional theory method. Oxide surface atoms with different coordination numbers show very different reactivity giving both molecular and dissociated adsorbed species. The methanol molecule requires lower coordination numbers of the active site than the isocyanic acid molecule for dissociative adsorption. The role of the acidic and basic sites has been considered and analyzed in terms of natural bond orbital charges. The main vibration frequencies have been compared with available infrared spectroscopic data.