Augmented Pairwise Additive Interaction Model for Lateral Adsorbate Interactions: The NO–CO Reaction System on Rh(100) and Rh(111)

Lateral adsorbate
interactions have been acknowledged to play an
important role in heterogeneous catalytic kinetics. To quantify such
energies efficiently and accurately, a lattice-gas-based augmented
pairwise additive interaction model was proposed. The model Hamiltonian
is defined as the summation over all isolated binding energies and
all pairwise interactions, with the pairwise interaction used for
each adsorbate pair consisting of the corresponding isolated pairwise
interaction and some needed modification terms if the surroundings
meet specific conditions. The parameters used in this augmented pairwise
additive interaction model for the NO–CO reaction system on
Rh(100) and Rh(111) were collected based on density functional theory
(DFT) calculations. The reliability of the model was examined by the
reproduction of some DFT-based predictions and experimental observations.
Results suggest that the lateral interactions on Rh(100) are relatively
short range and greatly susceptible to the lateral displacements of
adsorbates, whereas on Rh(111), the lateral interactions are relatively
long range and the lateral displacements of adsorbates are more limited.
In addition, the Brønsted–Evans–Polanyi relations
for adsorbate diffusion were constructed and a modification strategy
was proposed for certain diffusion processes. This work opens up the
possibility of accurate microkinetic modeling for this reaction system
with a faithful account of lateral interactions and motivates the
extensions to other complex surface systems.