Controlling turbulence in a surface chemical reaction by time-delay autosynchronization

Area of Science:

• Chemical kinetics
• Surface science
• Nonlinear dynamics

Background:

• Chemical turbulence, characterized by chaotic spatio-temporal patterns, poses challenges in controlling surface reactions.
• The catalytic CO oxidation on Pt(110) is a well-studied system exhibiting complex oscillatory and turbulent behaviors.

Purpose of the Study:

• To experimentally implement and evaluate a global time-delay feedback scheme for controlling chemical turbulence.
• To investigate the transition dynamics from turbulent to homogeneous oscillatory states.

Main Methods:

• Utilizing photoemission electron microscopy (PEEM) under ultrahigh vacuum (UHV) conditions to visualize reaction dynamics.
• Applying time-delay autosynchronization as a feedback control strategy.
• Conducting numerical simulations of a realistic reaction model to validate experimental findings.

Main Results:

• Demonstrated efficient suppression of chemical turbulence via time-delay autosynchronization.
• Observed hysteresis effects in the transition regime between turbulence and homogeneous oscillations.
• Identified a discontinuity in oscillation period at optimal delay times, supported by analytical phase equation studies.

Conclusions:

• Global time-delay feedback is an effective method for controlling chemical turbulence in surface reactions.
• The study provides insights into the complex dynamics and transition mechanisms of the CO oxidation reaction on Pt(110).
• Numerical simulations successfully reproduced experimental observations, validating the control strategy and reaction model.