Potential-dependent structures investigated at the perchloric acid solution/iodine modified Au(111) interface by...

Area of Science:

• Electrochemistry
• Surface Science
• Nanotechnology

Background:

• The electrified interface between electrode surfaces and electrolytes is crucial for electrochemical processes.
• Understanding atomic-level interfacial structures informs the design of electrochemical devices.

Purpose of the Study:

• To investigate the atomic-scale structure and hydration of an iodine-modified Au(111) electrode surface in perchloric acid.
• To correlate interfacial hydration changes with electrode potential using advanced microscopy.

Main Methods:

• Electrochemical frequency-modulation atomic force microscopy (EC-FM-AFM) was employed.
• Atomic resolution imaging and force-distance curve measurements were performed at varying electrode potentials.
• Cyclic voltammetry was used to characterize interfacial electrochemical behavior.

Main Results:

• Atomic resolution imaging of iodine adatoms on Au(111) was potential-dependent, achievable in the cathodic range but not the anodic range.
• Frequency shift measurements indicated weakened water structuring at anodic potentials, correlating with the loss of atomic resolution.
• Reversible changes in hydration and topography were observed upon potential cycling, consistent with cyclic voltammetry data.

Conclusions:

• Perchlorate anions influence interfacial hydration at anodic potentials without causing irreversible surface changes.
• Electrode potential dynamically controls interfacial water structuring and atomic imaging capabilities.
• EC-FM-AFM provides insights into potential-dependent interfacial dynamics at the nanoscale.