An Up-Scalable Solid-State Approach to Synthesize Iridium Nanoparticles on ATO for Water Splitting.

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Proton exchange membrane water electrolysis (PEMWE) requires efficient and affordable anode catalysts.
• Iridium dioxide (IrO2) is a key catalyst, but its high cost necessitates reduced iridium (Ir) loading.
• Conductive support materials can anchor Ir/IrO2, improving catalyst efficiency.

Purpose of the Study:

• To develop a straightforward and time-efficient synthesis protocol for iridium catalysts on antimony-doped tin oxide (ATO).
• To investigate the oxygen evolution reaction (OER) performance of Ir/ATO catalysts with reduced Ir loading.
• To enhance the commercial viability of PEMWE technology through cost-effective catalyst design.

Main Methods:

• A solid-state method was employed to deposit metallic iridium (Ir) onto antimony-doped tin oxide (ATO).
• Four catalyst samples with 50 wt% Ir loading were prepared using varying conditions, including NaOH in ethanol (Ir/ATO-NE).
• Electrochemical performance was evaluated using OER measurements and Tafel slope analysis. Material characterization included electron microscopy.

Main Results:

• The Ir/ATO-NE catalyst exhibited superior specific OER performance (340 A gIr−1 at 1.6 V vs RHE) compared to commercial IrO2 (282 A gIr−1).
• Ir/ATO-NE showed the lowest Tafel slope, indicating enhanced oxygen evolution kinetics.
• Electron microscopy confirmed uniform Ir nanoparticle size and complete NP coverage on the ATO support for the optimal sample.

Conclusions:

• A simple, efficient, and effective synthesis protocol for Ir catalysts on ATO for oxygen evolution in acidic media was established.
• The developed Ir/ATO-NE catalyst demonstrates high activity and durability, offering a promising alternative to commercial IrO2.
• This approach facilitates reduced iridium loading, contributing to more cost-effective PEMWE systems.