Achieving High Activity and Long-Term Stability towards Oxygen Evolution in Acid by Phase Coupling between CeO₂-Ir

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Efficient and stable catalysts are critical for the acidic oxygen evolution reaction (OER).
• Iridium-based catalysts are effective but often require high loadings.
• Developing novel catalyst structures can enhance performance and reduce precious metal usage.

Purpose of the Study:

• To synthesize and characterize CeO2-Ir heterojunctions supported on carbon nanotubes (CeO2-Ir/CNTs) for acidic OER.
• To evaluate the catalytic activity, mass activity, and stability of the synthesized catalysts.
• To investigate the role of the CeO2-Ir heterostructure in enhancing OER performance.

Main Methods:

• Solvothermal synthesis of CeO2-Ir/CNTs using a heterostructure strategy.
• Electrochemical testing for acidic oxygen evolution reaction (OER) performance.
• X-ray photoelectron spectroscopy (XPS) analysis to probe catalyst composition and electronic structure.

Main Results:

• CeO2-Ir/CNTs achieved 10.0 mA cm-2 at a low overpotential of 262.9 mV with 60.0 h stability.
• Exhibited a mass activity 58.8 times higher than commercial IrO2 (c-IrO2) using 15.3 times less Ir.
• XPS analysis indicated that CeO2 effectively modulated the chemical environment of Ir nanoparticles, enhancing catalytic properties.

Conclusions:

• CeO2-Ir/CNTs are highly efficient and stable electrocatalysts for acidic OER.
• The heterostructure strategy significantly boosts the mass activity of Ir catalysts.
• These findings highlight the potential of CeO2-Ir/CNTs as advanced anodic catalysts for water electrolysis.