Dissolution of Platinum Single Crystals in Acidic Medium

Area of Science:

• Electrochemistry
• Materials Science
• Surface Science

Background:

• Platinum's electrochemical properties are crucial for catalysis and electrocatalysis.
• Understanding the dissolution behavior of different platinum crystal facets is essential for optimizing electrode performance and stability.

Purpose of the Study:

• To investigate and compare the electrochemical dissolution behavior of distinct platinum single crystal basal planes (Pt(111), Pt(100), Pt(110)) and polycrystalline platinum (Pt(poly)).
• To correlate dissolution trends with surface structure energies and coordination of the platinum crystal planes.

Main Methods:

• Electrochemical treatments including potentiodynamic and potentiostatic methods were applied to platinum single crystals and polycrystalline platinum in 0.1 M perchloric acid (HClO4).
• On-line detection of transient platinum dissolution was performed using a scanning flow cell coupled to an inductively coupled plasma mass spectrometer (SFC-ICP-MS).

Main Results:

• Distinct trends in dissolution onset potentials and quantities were observed across the different platinum crystal planes.
• Platinum(111) exhibited a higher dissolution onset potential, indicating greater stability.
• The generalized trend for dissolution rates and quantities was found to be Pt(110) > Pt(100) ≈ Pt(poly) > Pt(111).

Conclusions:

• The surface structure energy and coordination of platinum crystal planes significantly influence their electrochemical dissolution behavior.
• Platinum(110) surfaces are the least stable and show the highest dissolution, while Pt(111) surfaces are the most resistant to dissolution.
• These findings provide critical insights for designing more stable platinum-based electrocatalysts and electrodes.