Nanofaceted platinum surfaces: a new model system for nanoparticle catalysts

Area of Science:

• Materials Science
• Electrochemistry
• Surface Science

Background:

• Nanoparticle electrocatalysts are crucial for various chemical reactions.
• Developing model systems to study catalyst behavior is essential for optimization.
• Platinum (Pt) is a widely used electrocatalyst material.

Purpose of the Study:

• To present a novel self-assembled model system for studying nanoparticle electrocatalysts.
• To investigate the formation and reversibility of platinum nanofacets.
• To understand the effect of CO adsorption on the electrochemical properties of these nanofaceted surfaces.

Main Methods:

• Self-assembly of platinum nanofacets by annealing single crystal surfaces (Pt(1+√3 1 1)).
• In-situ surface X-ray scattering for monitoring nanofacet formation.
• Scanning probe microscopy and cyclic voltammetry for surface characterization and electrochemical analysis.

Main Results:

• Annealing Pt(1+√3 1 1) in Ar/H2 yields a flat surface (<1 nm rms roughness).
• Annealing in pure air induces reversible and reproducible nanofaceting.
• CO adsorption/desorption cycles significantly modify cyclic voltammograms, attributed to electrochemical annealing of defects.

Conclusions:

• The developed Pt nanofacet system serves as a valuable model for electrocatalyst research.
• The reversible nanofaceting demonstrates tunable surface structures.
• Electrochemical annealing plays a role in modifying catalyst surface properties during operation.