Abstract:

The influences of A desorption and E-R mechanism on the phase transitions and self-oscillations in the irreversible catalytic oxidation reaction of A + 1/2 B2 → AB were studied in detail by Monte Carlo simulation. It was found that (1) the first order phase point observed in ZGB model disappears when A desorption is considered; (2) the second order phase transition point observed in ZGB model disappears when E-R mechanism concerned with A(g) and adsorbed B atom is considered; (3) there is no phase transitions in the reaction when both A desorption and E-R mechanism are considered; (4) there is obvious rate oscillation in the neighbourhood of the second order phase transition point of ZGB model, but only noise at other positions of A partial pressure, so there are no oscillations when E-R mechanism is considered or both E-R mechanism and A desorption are considered in our extended model.

Key words: Monte Carlo simulation, Surface catalytic reaction, Phase transition, Selfoscillation, Desorption, E-R mechanism