Chemisorption and reactivity of methanol on MgO thin films

Cristiana Di Valentin, Annalisa Del Vitto, Gianfranco Pacchioni, Stéphane Abbet, Anke S. Wörz, Ken Judai, Ueli Heiz

Research output: Contribution to journalArticlepeer-review

55 Scopus citations

Abstract

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.

Original languageEnglish
Pages (from-to)11961-11969
Number of pages9
JournalJournal of Physical Chemistry B
Volume106
Issue number46
DOIs
StatePublished - 21 Nov 2002
Externally publishedYes

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