Simulation of the life cycle of adsorbate islands on the Pt(1Â 0Â 0) surface during the NOÂ +Â NH3 reaction

Photoemission electron microscopy (PEEM) of the NO + NH3 reaction on a Pt(1 0 0) single crystal surface under UHV conditions reveals complicated dynamical behavior. As a rationalization for the observed spatio-temporal evolution of the surface a so-called 'island growth mechanism' was proposed. Here, we present the results of 1D simulations with a realistic 7-variable model that takes explicitly into account macroscopic surface defects on the catalyst. Depending on whether or not we consider site-blocking effects of coadsorbates on diffusing species, we obtain different patterns. The experimental PEEM data can be qualitatively reproduced in this way.