Ultrafine IrRu Nanoparticles toward Efficient Oxygen Evolution Reaction in Acidic Media

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Proton exchange membrane water electrolyzers (PEMWEs) are crucial for green hydrogen production using renewable energy.
• The oxygen evolution reaction (OER) in PEMWEs is limited by the sluggish kinetics of current electrocatalysts.
• Development of advanced electrocatalysts is essential to improve the efficiency of PEMWEs.

Purpose of the Study:

• To synthesize ultrafine Iridium-Ruthenium (IrRu) alloy nanoparticles as advanced electrocatalysts for OER.
• To investigate the OER activity, electrochemically active surface area (ECSA), specific activity (SA), and stability of the synthesized IrRu nanoparticles.
• To verify the performance of IrRu electrocatalysts in a PEMWE.

Main Methods:

• Synthesis of IrRu alloy nanoparticles via coprecipitation of IrCl3, RuCl3, and HCOONa, followed by heat treatment.
• Characterization of nanoparticle size (1.6 ± 0.3 nm) and ECSA (577.1 m² g⁻¹).
• Electrochemical evaluation of OER activity and stability using chronopotentiometry (CP) and testing in a PEMWE.

Main Results:

• Achieved low overpotentials for acidic OER: 230 mV and 194 mV at 10 mA cm⁻² with 51 and 204 μgIrRu cm⁻², respectively.
• Demonstrated high specific activity (SA) of 22.7 μA cm⁻² at 1.45 V vs RHE.
• Exhibited excellent stability during a 10-hour CP test and verified performance in a PEMWE.

Conclusions:

• The synthesized ultrafine IrRu alloy nanoparticles exhibit exceptional OER activity and stability.
• The enhanced performance is attributed to high ECSA, high SA, and synergistic electronic effects between Ir and Ru.
• IrRu alloy nanoparticles show great promise as efficient electrocatalysts for green hydrogen production in PEMWEs.