TY - JOUR
T1 - Chemisorption and reactivity of methanol on MgO thin films
AU - Di Valentin, Cristiana
AU - Del Vitto, Annalisa
AU - Pacchioni, Gianfranco
AU - Abbet, Stéphane
AU - Wörz, Anke S.
AU - Judai, Ken
AU - Heiz, Ueli
PY - 2002/11/21
Y1 - 2002/11/21
N2 - Methanol adsorption on MgO thin films has been studied by Fourier transform infrared (FTIR) and thermal desorption spectroscopies (TDS), and by ab initio cluster model calculations. Depending on the preparation conditions, films with various concentrations of defects have been obtained. These films exhibit different reactivity toward adsorbed methanol. In particular, at temperatures of 580 K, H2 is released from defect-rich films while no production of hydrogen is observed on defect-poor films. The calculations show that methanol can interact in three different ways with the surface giving rise to physisorption, chemisorption, or heterolytic dissociation into CH3O- and H+ fragments depending on the adsorption site. Chemisorption and dissociation occur only at defect sites, like low-coordinated ions at steps. Oxygen vacancies (F centers) are proposed as the sites present on the defect-rich films which are responsible for hydrogen release at high temperature.
AB - Methanol adsorption on MgO thin films has been studied by Fourier transform infrared (FTIR) and thermal desorption spectroscopies (TDS), and by ab initio cluster model calculations. Depending on the preparation conditions, films with various concentrations of defects have been obtained. These films exhibit different reactivity toward adsorbed methanol. In particular, at temperatures of 580 K, H2 is released from defect-rich films while no production of hydrogen is observed on defect-poor films. The calculations show that methanol can interact in three different ways with the surface giving rise to physisorption, chemisorption, or heterolytic dissociation into CH3O- and H+ fragments depending on the adsorption site. Chemisorption and dissociation occur only at defect sites, like low-coordinated ions at steps. Oxygen vacancies (F centers) are proposed as the sites present on the defect-rich films which are responsible for hydrogen release at high temperature.
UR - http://www.scopus.com/inward/record.url?scp=0037152955&partnerID=8YFLogxK
U2 - 10.1021/jp026399q
DO - 10.1021/jp026399q
M3 - Article
AN - SCOPUS:0037152955
SN - 1089-5647
VL - 106
SP - 11961
EP - 11969
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
IS - 46
ER -