0000000000255629
AUTHOR
E. E. Tornau
Surface phase transitions at O and CO catalytic reaction on Pd(111)
Abstract The model has been proposed to simulate numerically the reaction O + CO → CO2 and occurring phase transitions on Pd(1 1 1) surface. We calculate the phase diagram for this system by kinetic Monte Carlo method. It shows the phase transitions p ( 2 × 2 ) O → 3 × 3 R 30 O ° and p ( 2 × 2 ) O → 3 × 3 R 30 O ° → p ( 2 × 1 ) O with increase of CO coverage for room and intermediate temperatures, respectively, while in the low temperature limit the direct p(2 × 2)O → p(2 × 1)O phase transition is observed. We demonstrate that the reaction rate is the crucial factor determining the occurrence of the p(2 × 1)O phase and vanishing of the 3 × 3 R 30 O ° with decrease of temperature. The result…
Simulation of Reaction-Induced Phase Separation in Surface Alloy
Using kinetic Monte Carlo method we simulate the dynamics of biatomic Au0.3Ni0.7 surface alloy separation on Ni(111) due to Ni(CO)4 out-reaction. The experiment of Vestergaard et al. is modeled by counterbalancing dynamical processes and interactions between reactants. The simulations demonstrate step flow rate increase with CO coverage, cCO, in qualitative agreement with the experiment only for cCO <∼ 0.45 monolayer. Moreover, we demonstrate both CO influence on reaction process and Au domain formation.
Modelling of phase transitions and reaction at CO adsorption on oxygen precovered Pd(111)
Abstract Using the interaction parameters up to the third neighbors and activated form of O and CO diffusion and their reaction, the model has been proposed for Monte-Carlo simulations describing the catalytic O + CO → CO2 reaction and occurring phase transitions on Pd(1 1 1) surface. Upon adsorption of CO the pre-adsorbed oxygen transforms from p(2 × 2)O phase into 3 × 3 R 30 O ° and 3 × 3 R 30 O ° → p ( 2 × 1 ) O phases in the limit of room and moderate temperatures, respectively. We demonstrate that the kinetic effects determine both the occurrence of the p(2 × 1)O and disappearance of the 3 × 3 R 30 O ° phases at moderate and low temperatures, respectively. Using reaction rate as a fit …