Surface-Templated Assembly of Molecular Methanol on the Thin Film “29” Cu(111) Surface Oxide

Journal Article · Thu Jan 03 00:00:00 EST 2019 · Journal of Physical Chemistry. C

DOI:https://doi.org/10.1021/acs.jpcc.8b10284· OSTI ID:1599612

Therrien, Andrew J. ^[1]; Hensley, Alyssa J. R.  ^[2]; Hannagan, Ryan T. ^[1]; Schilling, Alex C. ^[1]; Marcinkowski, Matthew D. ^[1]; Larson, Amanda M. ^[1]; McEwen, Jean-Sabin  ^[3]; Sykes, E. Charles H.  ^[1]

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1. Tufts Univ., Medford, MA (United States)
2. Washington State Univ., Pullman, WA (United States)
3. Washington State Univ., Pullman, WA (United States); Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

Identifying and characterizing the atomic-scale interaction of methanol with oxidized Cu surfaces is of fundamental relevance to industrial reactions, such as methanol steam reforming and methanol synthesis. Here, we investigate the adsorption of methanol on the well-defined “29” Cu oxide surface, using a combination of experimental and theoretical techniques, and elucidate the atomic-scale interactions that lead to a unique spatial ordering of methanol on the oxide thin film. We determine that the methanol chain structures form first due to epitaxy with the underlying “29” oxide surface. Specifically, the geometry of the “29” oxide is such that there are spatially adjacent O^δ– sites, in the form of O adatoms, and Cu^δ+ species, within the Cu₂O-like rings, which allow for methanol to simultaneously bond to the surface via an O_methanol–Cu^δ+ dative bond and an OH_methanol–O^δ– hydrogen bond. The methanol–oxide bond strength outweighs the strength of methanol–methanol hydrogen bonds on the “29” Cu oxide, unlike methanol assembly on bare coinage metal surfaces on which hydrogen bonding between adjacent molecules leads to ordered arrays. Weak, long-range interactions lead to the formation of chains of only even numbers of methanol molecules. Together, this work reveals that, unlike that on metal surfaces, the corrugation of the oxide surface drives methanol adsorption to preferred binding sites, preventing intermolecular hydrogen bonding and dictating the adsorption geometry.

• Research Organization: Tufts Univ., Medford, MA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Science (SC), Biological and Environmental Research (BER); National Science Foundation (NSF)
• Grant/Contract Number: FG02-05ER15730; CBET-1653561
• OSTI ID: 1599612
• Journal Information: Journal of Physical Chemistry. C, Vol. 123, Issue 5; ISSN 1932-7447
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY