Effect of the ratio of reactants on the phase diagram of heterogeneous catalytic reactions: a Monte Carlo simulation study

This study considers models of the type (1/n)An+(1/m)Bm→AB to investigate the effect of size ratio of reactants (m/n) on the phase diagram of a particular reaction. For monomer–monomer and dimer–dimer models continuous and discontinuous transition points with a steady reactive window width are obtained. We have studied trimer–trimer (m=n=3) and monomer–trimer (m=3 and n=1) models. It is obvious that whenever the m/n size ratio is one a single transition point is observed at yA=0.5, which separates two poisoned states (where yA is concentration of A). However, a steady reactive window is obtained if the m/n size ratio is not equal to one. The width of the steady reactive window is a function of the m/n size ratio.