Lanthanides Regulated the Amorphization-Crystallization of IrO₂ for Outstanding OER Performance

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Research focuses on optimizing amorphous surfaces of iridium-based materials for enhanced oxygen evolution reaction (OER) activity.
• The amorphous IrO2 layer is crucial for overcoming limitations of the adsorbate evolution mechanism (AEM) in acidic conditions.

Purpose of the Study:

• To investigate the use of lanthanides to control the amorphization-crystallization process of IrO2.
• To explore the impact of lanthanide-induced crystalline-amorphous (c-a) interfaces on OER performance and stability.

Main Methods:

• Lanthanides were employed to inhibit iridium crystallization during calcination, promoting the formation of c-a interfaces in IrO2.
• Synthesized IrO2@LnIr1-xO2(OH)x structures (Ln = La-Lu) were characterized for their electrochemical properties.

Main Results:

• The synthesized IrO2@LuIr1-xO2(OH)x exhibited a mass activity of 128.3 A/gIr, a 14.6-fold increase compared to benchmark IrO2.
• All IrO2@LnIr1-xO2(OH)x structures showed low overpotentials (290-300 mV at 10 mA/cm2), indicating high OER efficiency.
• The c-a interface demonstrated efficient charge transfer and stabilized activated oxygen species.

Conclusions:

• Lanthanide-mediated c-a interface generation is a viable strategy for designing robust and highly active OER catalysts.
• The synergistic effects of surface-activated oxygen species and lanthanide-induced lattice strain enhance intrinsic OER activity.