Short-Range-Engineered Nd-Doped IrO_x Enables Oxide Path Mechanism for High-Performance PEM Water Electrolysis

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Proton-exchange-membrane water electrolysis (PEMWE) requires efficient anodes with low iridium content.
• Conventional iridium-based catalysts face an activity-stability trade-off.

Purpose of the Study:

• To design neodymium-doped amorphous iridium oxide (Nd-IrO_x) catalysts for PEMWE.
• To precisely control short-range structure and activate the oxide path mechanism (OPM).

Main Methods:

• Incorporation of Nd³⁺ into an amorphous IrO_x matrix.
• Optimization of edge-sharing [IrO₆] octahedra for lattice distortion and electronic modulation.
• Characterization of catalyst performance in acidic media.

Main Results:

• Nd-IrO_x catalysts exhibit an ultralow acidic oxygen evolution reaction (OER) overpotential of 254 mV at 10 mA cm^-2 with 520 h stability.
• PEMWE with ultralow Ir loading (0.5 mg_Ir cm^-2) achieved DOE-relevant current density (4 A cm^-2 at 1.9 V).
• Demonstrated remarkable 1000-h stability at 1 A cm^-2.

Conclusions:

• Short-range structural engineering in Ir-based oxides is a viable strategy for catalyst design.
• Optimized Nd-IrO_x catalysts offer fundamental insights for OER pathway control.
• This approach facilitates efficient hydrogen production through improved catalyst performance and longevity.