Dynamic Catalyst Restructuring and Interface Instabilities: A Combined Experimental and Computational Study

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In the bistable regime of the NH3+ O2 and the CH3OH + O2 reactions on a Rh(110) surface a novel type of interface instability has been observed recently. Under reaction conditions of equistability of the two phases the interface oxygen rich/oxygen poor is not stationary but exhibits localized excitations which travel pulse-like along the front line. In the current project we try to determine the mechanism of the traveling interface instabilities in a combined experimental/theoretical approach. Based on the idea that the instability is due to a coupling between reaction-induced surface roughening and local excitations of the reaction we try to set up a realistic mathematical model that reproduces the observed phenomena. In Hannover we will conduct in situ microscopy in order to identify the essential steps of the proposed mechanism. In close collaboration between the groups at Hannover and Moscow a realistic reaction-diffusion model shall be developed. The simulation and the analysis of the simulation results will be conducted by the Moscow group. If successful, the simulation would provide us with a potential mechanism for reaction-induced roughening in catalysis.