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Adsorption and reaction of methanol on Fe3O4(001)
- Source :
- Marcinkowski, M D, Adamsen, K C, Doudin, N, Sharp, M A, Smith, R S, Wang, Y, Wendt, S, Lauritsen, J V, Parkinson, G S, Kay, B D & Dohnálek, Z 2020, ' Adsorption and reaction of methanol on Fe 3 O 4 (001) ', Journal of Chemical Physics, vol. 152, no. 6, 064703 . https://doi.org/10.1063/1.5139418
- Publication Year :
- 2020
- Publisher :
- AIP Publishing, 2020.
-
Abstract
- The interaction of methanol with iron oxide surfaces is of interest due to its potential in hydrogen storage and from a fundamental perspective as a chemical probe of reactivity. We present here a study examining the adsorption and reaction of methanol on magnetite Fe3O4(001) at cryogenic temperatures using a combination of temperature programmed desorption, x-ray photoelectron spectroscopy, and scanning tunneling microscopy. The methanol desorption profile from Fe3O4(001) is complex, exhibiting peaks at 140 K, 173 K, 230 K, and 268 K, corresponding to the desorption of intact methanol, as well as peaks at 341 K and 495 K due to the reaction of methoxy intermediates. The saturation of a monolayer of methanol corresponds to ∼5 molecules/unit cell (u.c.), which is slightly higher than the number of surface octahedral iron atoms of 4/u.c. We probe the kinetics and thermodynamics of the desorption of molecular methanol using inversion analysis. The deconvolution of the complex desorption profile into individual peaks allows for calculations of both the desorption energy and the prefactor of each feature. The initial 0.7 methanol/u.c. reacts to form methoxy and hydroxy intermediates at 180 K, which remain on the surface above room temperature after intact methanol has desorbed. The methoxy species react via one of two channels, a recombination reaction with surface hydroxyls to form additional methanol at ∼350 K and a disproportionation reaction to form methanol and formaldehyde at ∼500 K. Only 20% of the methoxy species undergo the disproportionation reaction, with most of them reacting via the 350 K pathway.
- Subjects :
- 010304 chemical physics
Thermal desorption spectroscopy
Formaldehyde
General Physics and Astronomy
Disproportionation
010402 general chemistry
01 natural sciences
0104 chemical sciences
Hydrogen storage
chemistry.chemical_compound
Adsorption
chemistry
Desorption
0103 physical sciences
Physical chemistry
Reactivity (chemistry)
Methanol
Physical and Theoretical Chemistry
Subjects
Details
- ISSN :
- 10897690 and 00219606
- Volume :
- 152
- Database :
- OpenAIRE
- Journal :
- The Journal of Chemical Physics
- Accession number :
- edsair.doi.dedup.....b0ad197fa38b1dc866794563703d2544
- Full Text :
- https://doi.org/10.1063/1.5139418