Absorbing states in a catalysis model with anti-Arrhenius behavior

Area of Science:

• Chemical Engineering
• Physical Chemistry
• Materials Science

Background:

• Heterogeneous catalysis involves complex reaction dynamics influenced by temperature and monomer interactions.
• Anti-Arrhenius behavior, where reaction rates decrease with increasing temperature, presents unique challenges in catalytic modeling.
• Understanding phase transitions in catalytic systems is crucial for optimizing industrial processes.

Purpose of the Study:

• To investigate a heterogeneous catalytic model with competitive reactions between monomers A and B.
• To explore the effects of temperature-dependent anti-Arrhenius reaction mechanisms on system behavior.
• To determine the phase diagram and critical exponents of the model.

Main Methods:

• Utilized mean-field calculations, including site and pair approximations.
• Performed extensive Monte Carlo simulations to analyze the model's behavior.
• Calculated static, dynamic, and spreading exponents to characterize phase transitions.

Main Results:

• The model exhibits distinct absorbing and active phases separated by continuous phase transitions.
• The phase diagram was mapped in the y(A) versus temperature plane, where y(A) is the probability of monomer A reaching the catalyst.
• Despite diverse microscopic configurations of the absorbing state, the model belongs to the 2D directed percolation universality class.

Conclusions:

• The study successfully characterized the phase behavior and critical phenomena of a competitive heterogeneous catalytic model.
• Both Arrhenius and anti-Arrhenius reaction mechanisms yield identical critical exponents, confirming the robustness of the universality class.
• The findings contribute to a deeper understanding of reaction dynamics and phase transitions in catalytic systems.