Theoretical analysis of external noise and bistability in the catalytic CO oxidation on Pd(111)

We theoretically study the impact of an external noise on a kinetic mean-field model for the bistable catalytic CO oxidation on Pd(111) surfaces. A spatially homogeneous Gaussian white noise is imposed on the fraction of CO in the constant gas flow directed at the surface and the resulting stochastic system is analyzed by a set of Langevin equations. Using an adiabatic elimination technique, we are able to analyze the interplay between the noise and the kinetic bistability reported for this surface reaction in recent experimental studies. The analytical results predict a strong impact on the bistability phase diagram. The stochastic effects are analyzed by computing stationary solutions of the probability distribution functions and the transition times between the active and inactive states of the bistable region. We also introduce an effective potential description that allows us to analyze the impact of noise.