Alkali Metal Cation Effects in Structuring Pt, Rh, and Au Surfaces through Cathodic Corrosion

Area of Science:

• Electrochemistry
• Materials Science
• Surface Science

Background:

• Cathodic corrosion etches metallic surfaces, creating nanoparticles and oriented features.
• It's used for nanostructuring electrodes but lacks mechanistic chemical understanding.
• Alkali metal cations are suspected to be crucial for its mechanism and facet control.

Purpose of the Study:

• To explore the mechanism of cathodic corrosion on Pt, Rh, and Au.
• To elucidate the role of alkali metal cations (LiOH, NaOH, KOH) in this process.
• To understand the factors controlling surface morphology and facet preference.

Main Methods:

• Experimental investigation of cathodic corrosion.
• Theoretical calculations using density functional theory (DFT).
• Analysis of Pt, Rh, and Au in various alkali metal hydroxides.

Main Results:

• Cations adsorb during cathodic corrosion, influencing onset potential and surface morphology.
• Adsorbed hydrogen also plays a significant role in controlling surface features.
• Evidence suggests cathodic corrosion may involve an intermediate ternary metal hydride.

Conclusions:

• Electrolyte cations and adsorbed hydrogen are key to controlling cathodic corrosion.
• Understanding these factors allows for tailored metal surface nanostructuring.
• Provides guidelines for optimizing cathodic corrosion for specific metal applications.