Synergistic Ruthenium-Doped Amorphous IrO_x Matrix for Robust Oxygen Evolution

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Iridium oxides (IrOₓ) are key catalysts for the acidic oxygen evolution reaction (OER).
• Their performance is limited by a trade-off between catalytic activity and long-term stability.
• Developing stable and active OER catalysts is crucial for energy applications.

Purpose of the Study:

• To enhance the catalytic activity and stability of iridium oxides for the oxygen evolution reaction.
• To investigate the synergistic effects of ruthenium doping in an amorphous iridium oxide matrix.
• To overcome the intrinsic performance limitations of iridium-based oxides.

Main Methods:

• Nitrate-assisted synthesis of ultrathin Ru-doped amorphous IrOₓ nanosheets.
• Spectroscopic analysis (e.g., XPS, XAS) to characterize material properties.
• Density Functional Theory (DFT) calculations to understand electronic structure and reaction mechanisms.

Main Results:

• Ultrathin (2.36 nm) Ru-doped amorphous IrOₓ nanosheets with high surface area were synthesized.
• Atomically dispersed Ru dopants optimized the Ir d-band electronic structure via charge transfer.
• The optimized catalyst (Ru₀.₀₇₃₈-IrOₓ) achieved 10 mA cm⁻² at 225 mV overpotential with >100 h stability.
• The mechanism shifted to the stable adsorbate evolution pathway, suppressing degradation.

Conclusions:

• Synergistic doping of amorphous IrOₓ with Ru offers a promising strategy for advanced OER catalysts.
• The optimized catalyst significantly outperforms commercial IrO₂ and RuO₂.
• This approach provides a pathway to overcome stability-activity trade-offs in iridium-based OER catalysts.