Phase Diagram of Catalytic Oxidation of CO on the Surface--Subsurface of a Body-Centred Cubic Structure with Eley--Rideal Process: A Monte Carlo Simulation

Monte Carlo simulation is used to explore the effects of the Eley-Rideal (ER) process on the phase diagram of the Langmuir--Hinshelwood (LH) type monomer--dimer (CO--O₂) catalytic reaction on the surface and subsurface of a body-centred cubic structure, which extends to only two layers in the z-direction. The dimer (O₂) is adsorbed in such a way that it takes one surface site whereas the second site is from the subsurface. For this mechanism, an interesting situation develops. The production rate of CO₂ is found to be consistent with experiment. The qualitative trend of the surface oxygen coverage is not consistent with the experimental situation in one model while it is found to be consistent with that in another model, i.e. the coverage of surface oxygen decreases slowly with increase of concentration of CO (yCO). Moreover, the production of CO₂ can be predicted in the form of a mathematical relation.