Water Electrolysis Using a Porous IrO₂/Ti/IrO₂ Catalyst Electrode and Nafion Membranes at Elevated Temperatures

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Development of efficient catalysts for water electrolysis is crucial for hydrogen production.
• High-temperature operation of membrane electrode assemblies (MEAs) presents challenges for electrolyte stability.

Purpose of the Study:

• To synthesize and characterize porous IrO2/Ti/IrO2 catalyst electrodes for water electrolysis.
• To evaluate the performance of these electrodes at elevated temperatures (up to 150 °C).
• To investigate the structural stability of Nafion and Aquivion membranes under high-temperature conditions.

Main Methods:

• Fabrication of porous IrO2/Ti/IrO2 electrodes using different surface treatments.
• Assembly of membrane electrode assemblies (MEAs) with Nafion115 as the electrolyte.
• Electrochemical characterization of electrodes during water electrolysis.
• Structural analysis of polymer membranes using small-angle X-ray scattering (SAXS).

Main Results:

• Porous IrO2/Ti/IrO2 electrodes exhibited high current densities due to their nanostructure.
• Sheet resistance varied among samples, with samples 2 and 3 showing lower resistance than sample 1.
• Nafion and Aquivion membranes maintained structural integrity up to 80 °C, but significant domain growth occurred above 120 °C, with irreversible structural changes.

Conclusions:

• Porous IrO2/Ti/IrO2 electrodes show promise for high-performance water electrolysis.
• Elevated temperatures above 120 °C negatively impact the structural stability of Nafion and Aquivion membranes.
• Further research is needed to develop robust electrolytes for high-temperature water electrolysis applications.