Stationary spatial patterns during bulk CO electrooxidation on platinum.

Area of Science:

• Electrochemistry
• Surface Science
• Chemical Kinetics

Background:

• Understanding pattern formation is crucial for controlling electrochemical reactions.
• Carbon monoxide electrooxidation on platinum is a key process in catalysis and fuel cells.
• Self-organization phenomena can lead to complex behaviors in electrochemical systems.

Purpose of the Study:

• To experimentally investigate and mathematically model pattern formation during CO electrooxidation on Pt ring electrodes.
• To analyze the influence of interfacial potential drop on pattern characteristics.
• To elucidate the underlying mechanisms of pattern self-organization.

Main Methods:

• Experimental electrochemical measurements using a potential probe on Pt ring electrodes.
• Potentiostatic control in dilute acidic and basic supporting electrolytes.
• Development and analysis of a mathematical model for pattern formation.

Main Results:

• Observation of stationary, self-organized potential patterns under potentiostatic conditions.
• Demonstration that pattern amplitude and shape are modifiable via local potential perturbation.
• Mathematical model indicates a subcritical Turing-like bifurcation leading to pattern instability.

Conclusions:

• The homogeneous state of CO electrooxidation on Pt electrodes is unstable.
• Multiple patterned electrode states can coexist over a range of parameters.
• The study provides insights into the complex dynamics of electrochemical surface reactions.