jp500255f_si_001.pdf (1.34 MB)
Ethanol Conversion on Cyclic (MO3)3 (M = Mo, W) Clusters
journal contribution
posted on 2014-03-06, 00:00 authored by Zhenjun Li, Zongtang Fang, Matthew
S. Kelley, Bruce D. Kay, Roger Rousseau, Zdenek Dohnalek, David A. DixonThe reactions of ethanol (CH3CH2OD) over
cyclic (MO3)3 (M = Mo, W) clusters were studied
experimentally and computationally. The cyclic clusters were prepared
by sublimation of MoO3 and WO3 powders in a
vacuum. To evaluate the cluster activity in dehydration, dehydrogenation,
and condensation reactions, they were suspended in an ethanol matrix
on an inert substrate, graphene monolayer on Pt(111). The reaction
products formed upon heating were followed and quantified using temperature-programmed
desorption. The experimental results were corroborated using coupled
cluster CCSD(T) calculations at DFT optimized geometries that provide
quantitative molecular-scale information on the reaction mechanisms.
The dehydration and dehydrogenation of ethanol probe both the Lewis/Brønsted
acid/base and redox properties of the metal centers. The overall conversion
of the alcohol is governed by the Lewis acidity of the metal center,
and product selectivities, as determined by the relative weights of
dehydrogenation and dehydration, are governed by the reducibility
of the metal center.