Structural kinetics studies on phase transitions of the Bi UPD layer between the (2 x 2) and (p x square root[3])...

Area of Science:

• Surface science
• Electrochemistry
• Materials science

Background:

• Bismuth (Bi) structures on gold (Au)(111) exhibit phase transitions.
• Understanding these transitions is key for surface chemistry and materials applications.

Purpose of the Study:

• To investigate the kinetics and models of phase transitions between (2 x 2) and (p x square root[3])-Bi structures on Au(111).
• To compare structural and electrochemical viewpoints of these phase transitions.

Main Methods:

• Electrochemical methods.
• Time-resolved surface X-ray diffraction.
• Monitoring current and X-ray intensity transients during phase transitions.

Main Results:

• Phase transition models derived from X-ray diffraction and electrochemical measurements differed.
• For (p x square root[3]) to (2 x 2) transition: X-ray indicated nucleation-growth, electrochemistry suggested Langmuir process.
• For reverse transition: X-ray indicated Langmuir adsorption, electrochemistry suggested nucleation-growth.

Conclusions:

• Electrochemical current transient curves may not always accurately represent phase transition models.
• Structural analysis using techniques like surface X-ray diffraction is fundamental for accurate phase transition studies.
• Discrepancies highlight the complexity of surface phase transition mechanisms.