Stability limits of tin-based electrocatalyst supports.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Tin-based oxides are promising catalyst supports for fuel cells and electrolyzers due to their conductivity.
• Dopant corrosion in these oxides can significantly degrade performance.
• Understanding dissolution behavior is critical for material stability in electrochemical devices.

Purpose of the Study:

• To investigate the potential-dependent dissolution rates of indium tin oxide (ITO), fluorine doped tin oxide (FTO), and antimony doped tin oxide (ATO).
• To evaluate the stability of these oxides across a wide potential window (-0.6 to 3.2 V_RHE) in a 0.1 M H₂SO₄ electrolyte.
• To correlate observed dissolution potentials with thermodynamic data for mechanism elucidation.

Main Methods:

• Electrochemical characterization of ITO, FTO, and ATO in 0.1 M H₂SO₄.
• Potentiodynamic sweeps were performed over a broad potential range (-0.6 to 3.2 V_RHE).
• Dissolution rates were analyzed as a function of applied potential, identifying cathodic and anodic dissolution phenomena.

Main Results:

• All tested oxides exhibited cathodic dissolution during electrochemical reduction.
• Anodic dissolution occurred upon oxidation of the reduced electrode and during oxygen evolution.
• Fluorine doped tin oxide (FTO) showed the highest stability under anodic conditions, while ITO exhibited significant dissolution, and ATO showed moderate dissolution.

Conclusions:

• The stability of doped tin oxides varies significantly with applied potential and oxide composition.
• FTO is the most robust material among those studied for applications involving anodic potentials.
• Understanding dissolution mechanisms is key to developing durable tin oxide-based catalyst supports.