Titanium Oxynitride-Supported Iridium Electrocatalysts for Efficient and Durable Acidic Oxygen Evolution Reaction

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Iridium-based materials are leading electrocatalysts for the acidic oxygen evolution reaction (OER).
• Developing efficient and stable electrocatalysts is crucial for energy conversion technologies.
• Titanium oxynitride is explored as a support material for iridium-based catalysts.

Purpose of the Study:

• To develop an efficient and low-iridium electrocatalyst for the acidic OER.
• To investigate the role of the support material in enhancing catalyst performance.
• To demonstrate a feasible approach for improving acidic OER electrocatalysts.

Main Methods:

• Anchoring a low-iridium electrocatalyst onto a titanium oxynitride support.
• Electrochemical characterization in 0.5 M H2SO4.
• Long-term stability testing at a current density of 10 mA cm-2.

Main Results:

• Achieved an overpotential as low as 278 mV for the acidic OER.
• Demonstrated robust stability exceeding 1000 hours.
• Identified in situ formation of high valence Ir(VI) sites due to support interaction, responsible for superior performance.

Conclusions:

• Rational design of support materials can significantly enhance the activity and stability of iridium-based electrocatalysts.
• The developed low-iridium catalyst offers a promising alternative for acidic OER applications.
• This work presents a viable strategy for advancing electrocatalyst design for demanding electrochemical reactions.