Abstract
Hydrogen-transfer steps are a poorly studied and rarely proposed class
of elementary reactions in heterogeneous catalysis over metal
surfaces. In these steps, a hydrogen atom that is attached to the
carbon in one surface species transfers to a carbon atom of another
species. UBI-QEP calculations of the activation energies for three
model surfaces representing substrates with strong, weak, and
intermediate chemisorption abilities, combined with UBI-QEP/DFT data
for the Pt(111) surface, suggest that there is no great energetic
impediment to these steps. Therefore, they should not be arbitrarily
ignored when building mechanisms of hydrocarbon conversions over metal
surfaces. Moreover, kinetics simulations show that conditions are
possible under which one-step hydrogen transfer is faster than the
two-step process with the formation of adsorbed hydrogen.
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