MONTE-CARLO STUDY OF SUBSURFACE EFFECT ON CATALYTIC SURFACE-REACTIONS

The effect of the subsurface in monomer-dimer (CO-O-2) surface reactio n is studied by Monte Carlo simulation. The presence of the subsurface adds some extra reaction steps to the usual three. It is shown that t he presence of the subsurface favours the enhancement of the steady re active state by reducing appreciably the poisoning of the surface by t he adsorbed dimer atoms. Under certain conditions the usual second ord er phase transition in CO-O-2 reaction can be eliminated. The role pla yed by the two way diffusion of adsorbed dimer atoms between surface a nd subsurface in the variation of steady reactive state is clearly ill ustrated. (C) 1997 American Institute of Physics.