Dissociation Free Energy Profiles for Water and Methanol on TiO2 Surfaces

VERONICA M. SANCHEZ,JULIE COJULUN, DAMIAN SCHERLIS

JOURNAL OF PHYSICAL CHEMISTRY C

AMER CHEMICAL SOC

Año: 2010 vol. 114 p. 11522 - 11526

1932-7447

   The umbrella sampling methodology is applied in the framework of density functional theory andCar-Parrinello molecular dynamics simulations to obtain the free energy profiles for the dissociationof methanol and water on stoichiometric TiO2 surfaces. In particular, we study the dissociationof water on rutile (110) and anatase (101), and the dissociation of the O-H and C-O bonds ofmethanol on anatase (101). We discuss the reaction free energies and activation barriers of theseprocesses in the light of experiments and previous simulations at zero temperature. The entropiccontribution to the reaction free energy is found to be positive for the dissociation of water andnegative for the dissociation of methanol.