Methanol O–H Bond
Dissociation on H‑Precovered
Gold Originating from a Structure with a Wide Range of Surface Stability
- Publication date
- Publisher
Abstract
Gold has been shown to exhibit promising catalytic activity,
and
understanding the fundamental interactions of reactants and hydrogen
atoms on a gold surface is key to gaining insight into hydrogenation
reaction mechanisms. In this paper, we report that the adsorption
of methanol onto a H-precovered Au(111) surface induces an adsorbate
structure, or set of structures, on the surface involving both methanol
and hydrogen adatoms with a wide range of stability on the surface.
Coadsorption of H/MeOD or D/MeOH indicates H/D exchange between the
two surface species, providing evidence that the H-precovered gold
surface can dissociate the methanol O–H bond at low temperature
(<120 K). These isotopic experiments also demonstrate that hydrogen/deuterium
atoms released from a methanol molecule desorb at higher temperatures
than hydrogen/deuterium atoms originating from the surface, providing
insight into the adsorbate structure(s) present. Additionally, the
presence of MeOH on the surface is shown to inhibit the ability of
adsorbed MeOD to undergo hydrogen exchange, providing additional clues
regarding the exchange reaction mechanism. These phenomena are also
shown to exist for ethanol on H-precovered Au(111), suggesting that
this behavior may be common to alcohols or species with an O–H
functional group in general. These observations give insight into
the behavior of the O–H group on a gold surface, which can
aid in determining reaction mechanisms and directing future catalytic
research