Strong Heteroatomic Bond-Induced Confined Restructuring on Ir-Mn Intermetallics Enable Robust PEM Water Electrolyzers

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Low-iridium electrocatalysts are vital for proton exchange membrane (PEM) water electrolysis's oxygen evolution reaction (OER).
• Controlling the in situ reconstruction of iridium-based catalysts for better kinetics is a significant challenge.

Purpose of the Study:

• To develop an atomic ordering strategy to modulate catalyst surface restructuring and overcome the activity/stability trade-off.
• To design self-stabilizing amorphous (oxy)hydroxides on iridium-manganese intermetallic (IMC) catalysts for enhanced OER performance.

Main Methods:

• Utilized an atomic ordering strategy on an Ir-Mn intermetallic (IMC) model.
• Employed combined in situ/ex situ characterizations and theoretical analysis.
• Investigated surface-confined reconstruction and heteroatom bonding effects.

Main Results:

• The strategy induced rational surface reconstruction, forming self-stabilizing amorphous (oxy)hydroxides.
• Strong Ir-O-Mn covalent units weakened the OOH* formation barrier and promoted H2O conversion, suppressing lattice oxygen participation.
• A PEM cell with Ir-Mn IMC achieved 3.0 A/cm² at 1.851 V (80°C) and stable operation at 2.0 A/cm² for over 2,000 hours.

Conclusions:

• The atomic ordering strategy effectively breaks the activity/stability trade-off in OER electrocatalysts.
• Ir-Mn IMC demonstrates promising application in PEM water electrolysis with reduced hydrogen production cost.
• Highlights the importance of surface-confined evolution triggered by strong heteroatom bonds for catalyst design.