CO-activator model for reconstructing Pt(100) surfaces: local microstructures and chemical turbulence

Area of Science:

• Surface Science
• Chemical Kinetics
• Materials Science

Background:

• CO adsorption and oxidation on platinum surfaces are crucial in catalysis.
• Pt(100) surfaces exhibit complex phase transitions under CO exposure.
• Understanding surface inhomogeneity is key to predicting catalytic behavior.

Purpose of the Study:

• To model CO adsorption and catalytic oxidation on inhomogeneous Pt(100) surfaces.
• To investigate the CO-induced surface transition from reconstructed to bulk-like phases.
• To elucidate the nature of irregular oscillations on Pt(100) surfaces.

Main Methods:

• Computational modeling of CO adsorption and catalytic CO oxidation.
• Analysis of nonequilibrium bistable behavior during surface phase transitions.
• Characterization of critical bifurcation points and fluctuations.

Main Results:

• Identified a bistable region with coexistence of hexagonal and (1x1) phases, critical at approximately 680 K and 10 Torr.
• Observed nonuniform oscillations with random standing waves of adsorbate concentrations.
• Demonstrated that spatial deformations of wave fronts provide insight into irregular oscillations.

Conclusions:

• The CO-induced surface transition on Pt(100) exhibits nonequilibrium bistable behavior.
• Fluctuations near the critical point lead to unique behaviors distinct from hysteresis.
• Modeling reveals nonuniform oscillations and spatial wave front deformations on inhomogeneous Pt(100) surfaces.