Identifying the Thermal Decomposition Mechanism of Guaiacol on Pt(111): An Integrated X-ray Photoelectron Spectroscopy and Density Functional Theory Study

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Details zur Publikation

Autor(en): Hensley AJR, Woeckel C, Gleichweit C, Gotterbarm K, Papp C, Steinrück HP, Wang Y, Denecke R, Mcewen JS
Zeitschrift: Journal of Physical Chemistry C
Verlag: AMER CHEMICAL SOC
Jahr der Veröffentlichung: 2018
Band: 122
Heftnummer: 8
Seitenbereich: 4261-4273
ISSN: 1932-7447


Abstract

Using a concerted effort from both experiment and theory, we determine the thermal decomposition mechanism for guaiacol on Pt(111), a reaction of interest in the area of bio-oil upgrading. This work serves as a demonstration of the power of combining in situ temperature-programmed X-ray photoelectron spectroscopy cos (TPXPS) and density functional theory (DFT) to elucidate complex reaction mechanisms occurring on heterogeneous surfaces. At low temperature (230 K), guaiacol was found to chemisorb with the aromatic ring parallel to the Pt(111) surface with five distinct carbon species and three oxygen species. As the temperature was increased, TPXPS showed several significant changes to the surface species. The increase in the species associated with the decomposition of the functional groups of guaiacol is followed by their subsequent disappearance and an increase in the nonaromatic carbon signal. On the basis of an energetic analysis of the various mechanisms using DFT, along with the comparison of the experimentally and theoretically derived core-level binding energies, we determined that guaiacol's decomposition mechanism occurs via the dehydrogenation of both the methyl and hydroxyl functional groups, followed by demethylation of the CH2 or CH group to form 1,2-benzoquinone. Further heating to above 375 K likely breaks the aromatic ring and results in the rapid formation and desorption of CO, accounting for the disappearance of the 0 is signal above 450 K These results show that a knowledgeable application of TPXPS and DFT can result in the quantitative identification of surface species during complex reactions, providing insight useful for the design of future heterogeneous surfaces.


FAU-Autoren / FAU-Herausgeber

Gleichweit, Christoph
Lehrstuhl für Physikalische Chemie II
Gotterbarm, Karin
Lehrstuhl für Physikalische Chemie II
Papp, Christian PD Dr.
Lehrstuhl für Physikalische Chemie II
Steinrück, Hans-Peter Prof. Dr.
Lehrstuhl für Physikalische Chemie II


Autor(en) der externen Einrichtung(en)
Universität Leipzig
Washington State University (WSU)


Zitierweisen

APA:
Hensley, A.J.R., Woeckel, C., Gleichweit, C., Gotterbarm, K., Papp, C., Steinrück, H.-P.,... Mcewen, J.-S. (2018). Identifying the Thermal Decomposition Mechanism of Guaiacol on Pt(111): An Integrated X-ray Photoelectron Spectroscopy and Density Functional Theory Study. Journal of Physical Chemistry C, 122(8), 4261-4273. https://dx.doi.org/10.1021/acs.jpcc.7b10006

MLA:
Hensley, Alyssa J. R., et al. "Identifying the Thermal Decomposition Mechanism of Guaiacol on Pt(111): An Integrated X-ray Photoelectron Spectroscopy and Density Functional Theory Study." Journal of Physical Chemistry C 122.8 (2018): 4261-4273.

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Zuletzt aktualisiert 2018-10-09 um 17:08

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