Standing fronts in oscillatory reactions on composite catalytic surfaces

We present Monte Carlo simulations of a standing reaction front formed duri ng NO reduction by H on a catalyst consisting of two metal strips. One stri p (to the right) is considered to be catalytically active. Specifically, th e reaction is assumed to occur on Pt(1 0 0). The other strip (to the left) is catalytically inactive but can adsorb NO. The processes on the two strip s are coupled via NO diffusion over their boundary. Kinetic oscillations re sult from NO-induced restructuring of the Pt(l 0 0) surface. The reaction f ronts obtained for this model are quite unusual. For example, the NO covera ge may be low on the left sublattice, high in a narrow zone on the right su blattice near the metal-metal boundary, and then again relatively low. Thes e findings illustrate richness of spatio-temporal patterns which can be obs erved in heterogeneous catalytic reactions on the mesoscopic scale. (C) 200 1 Elsevier Science B.V. All rights reserved.