Post-Selenium-Leaching Induced Fast Micro-Bubble Detachment on Nickel-Iron-Based OER Catalyst for Efficient AEM-WE.

Area of Science:

• Electrochemistry
• Materials Science
• Green Energy

Background:

• Efficient and durable oxygen evolution reaction (OER) catalysts are essential for anion exchange membrane water electrolysers (AEM-WE).
• AEM-WE are crucial for green hydrogen production using renewable energy sources.
• Optimizing mass transport and catalyst stability are key challenges in OER.

Purpose of the Study:

• To investigate the impact of selenium (Se) modification on nickel-iron layered double hydroxide (NiFe) OER catalysts.
• To understand how Se influences micro-bubble formation and detachment for improved mass transport.
• To evaluate the performance and durability of Se-modified NiFe catalysts in AEM-WE.

Main Methods:

• Synthesis of nickel-iron layered double hydroxide-based catalysts with selenium (NiFeSe).
• Electrochemical characterization of OER performance, including overpotential and durability tests in 1 M KOH.
• Assessment of micro-bubble dynamics and mass transport effects.
• Testing the catalyst in a practical anion exchange membrane water electrolyser (AEM-WE) device.

Main Results:

• Selenium modification enhanced surface roughness and facilitated rapid detachment of smaller oxygen bubbles.
• The NiFeSe catalyst achieved a low overpotential of 190 mV at 1000 mA cm⁻² with over 2000 h durability in 1 M KOH.
• In a practical AEM-WE, the catalyst reached 8800 mA cm⁻² at 2.0 V and operated continuously for over 3000 h at 1000 mA cm⁻².
• Selenium-induced micro-bubble dynamics significantly improved mass transport and catalytic efficiency.

Conclusions:

• Selenium modification is a promising strategy for developing advanced OER catalysts.
• Optimized micro-bubble formation and detachment are critical for enhancing mass transport in AEM-WE.
• The NiFeSe catalyst demonstrates high efficiency and durability for industrial green hydrogen production.