SUBSURFACE OXYGEN IN THE CO OXIDATION REACTION ON PT(110) - EXPERIMENTS AND MODELING OF PATTERN-FORMATION

New experimental evidence on the formation of spatio-temporal concentr ation patterns as imaged by photoemission electron microscopy (PEEM) s upports our earlier kinetic model for subsurface oxygen formation in t he CO oxidation reaction on Pt(110). Extensive experimental data on ox ygen island growth and conversion is used to derive the activation ene rgy and the preexponential factor for the process of subsurface oxygen formation. We find that under reaction conditions formation of subsur face oxygen may significantly influence properties of traveling concen tration waves. Instead of annihilation of two colliding waves, their r eflection and two-into-one collision events are observed in the experi ments. This behavior is correctly reproduced by the model.