6 research outputs found
The Active Phase of Palladium during Methane Oxidation
The active phase of Pd during methane oxidation is a
long-standing
puzzle, which, if solved, could provide routes for design of improved
catalysts. Here, density functional theory and in situ surface X-ray
diffraction are used to identify and characterize atomic sites yielding
high methane conversion. Calculations are performed for methane dissociation
over a range of Pd and PdO<sub><i>x</i></sub> surfaces and
reveal facile dissociation on either under-coordinated Pd sites in
PdO(101) or metallic surfaces. The experiments show unambiguously
that high methane conversion requires sufficiently thick PdO(101)
films or metallic Pd, in full agreement with the calculations. The
established link between high activity and atomic structure enables
rational design of improved catalysts
Activation of Ultrathin Oxide Films for Chemical Reaction by Interface Defects
Periodic density functional theory calculations revealed strong enhancement of chemical reactivity by defects located at the oxide-metal interface for water dissociation on ultrathin MgO films deposited on Ag(100) substrate. Accumulation of charge density at the oxide-metal interface due to irregular interface defects influences the chemical reactivity of MgO films by changing the charge distribution at the oxide surface. Our results reveal the importance of buried interface defects in controlling chemical reactions on an ultrathin oxide film supported by a metal substrate.close1