Title: Adsorption and reaction of methanol on Fe₃O₄ (001)

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 the 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. We report the methanol desorption profile from Fe₃O₄(001) is complex, exhibiting peaks at 145, 175, 238, and 273 K, corresponding to the desorption of intact methanol, as well as peaks at 350 and 500 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 a methoxy and hydroxy intermediates by 180 K, which remains on the surface above room temperature after intact methanol has desorbed. The methoxymore » 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.« less

Authors:

Marcinkowski, Matthew D. ^[1]; Adamsen, Kræn C. ^[2]; Doudin, Nassar ^[1]; Sharp, Marcus A.  ^[3];

• Search DOE PAGES for author "Sharp, Marcus A."
• Search DOE PAGES for ORCID "0000-0002-2599-8212"

Smith, Ronald Scott  ^[1];

• Search DOE PAGES for author "Smith, Ronald Scott"
• Search DOE PAGES for ORCID "0000-0002-7145-1963"

Wang, Yang ^[1]; Wendt, Stefan ^[2]; Lauritsen, Jeppe V.  ^[2];

• Search DOE PAGES for author "Lauritsen, Jeppe V."
• Search DOE PAGES for ORCID "0000-0003-4953-652X"

Parkinson, Gareth S.  ^[4];

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• Search DOE PAGES for ORCID "0000-0003-2457-8977"

Kay, Bruce D. ^[1]; Dohnálek, Zdenek  ^[3]

• Search DOE PAGES for author "Dohnálek, Zdenek"
• Search DOE PAGES for ORCID "0000-0002-5999-7867"

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+ Show Author Affiliations

1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Physical and Computational Sciences Directorate and Inst. for Integrated Catalysis
2. Aarhus Univ. (Denmark)
3. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Physical and Computational Sciences Directorate and Inst. for Integrated Catalysis; Washington State Univ., Pullman, WA (United States)
4. Vienna Univ. of Technology (Austria). Inst. of Applied Physics

Publication Date:

Mon Feb 10 00:00:00 EST 2020

Research Org.:

Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER); USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences, and Biosciences Division; Innovation Fund Denmark; Austrian Science Fund (FWF) START

OSTI Identifier:

1602775

Alternate Identifier(s):

OSTI ID: 1598731

Report Number(s):

PNNL-SA-149459
Journal ID: ISSN 0021-9606; TRN: US2104675

Grant/Contract Number:  

AC05-76RL01830; 6151-00008B; Y 847-N20

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Chemical Physics

Additional Journal Information:

Journal Volume: 152; Journal Issue: 6; Related Information: This article is part of the JCP Special Topic on Oxide Chemistry and Catalysis.; Journal ID: ISSN 0021-9606

Publisher:

American Institute of Physics (AIP)

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY