par De Decker, Yannick ;Baras, Florence
Référence The European physical journal. B. Condensed matter physic, 78, 2, page (173-186)
Publication Publié, 2010
Article révisé par les pairs
Résumé : We study the dynamics of a class of catalytic surface reactions in which an adsorbed molecule undergoes dissociation giving oxygen, which then rapidly reacts with H adatoms to give water. The reaction-diffusion equations predict bistability and explosive transients similar to those observed in several low-pressure experiments. Kinetic Monte Carlo simulations reveal however that the dynamics can be strongly affected by spontaneous, inhomogeneous fluctuations of composition on the surface. In particular, bifurcation points can be displaced and the explosive character of the transients can be lost, depending on a subtle balance between the rate of reaction and the mobility of the decomposing species. These effects can be quantified on the basis of a stochastic formulation of the dynamics taking into account spatial correlations. This approach allows to better delimit the applicability of the traditional reaction-diffusion modelling in the case of reactions such as the reduction of NO x or SO x species on catalytic surfaces. © 2010 EDP Sciences, Società Italiana di Fisica, Springer-Verlag.