Entropy-Enhancing Strategy Enables Highly Efficient Pt Utilization for High-Temperature H₂O-CO₂ Coelectrolysis

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• High-temperature solid oxide electrolysis cells (SOECs) efficiently convert H2O and CO2 into fuels.
• Platinum (Pt) is a highly effective catalyst for this process but is prohibitively expensive.
• Reducing Pt loading while maintaining catalytic activity is crucial for economic viability.

Purpose of the Study:

• To develop cost-effective catalysts for coelectrolysis of H2O and CO2.
• To enhance Pt utilization efficiency and catalytic performance in solid oxide electrolysis.
• To investigate the role of entropy in stabilizing Pt-based alloy catalysts.

Main Methods:

• Computational simulations including ab initio molecular dynamics and density functional theory (DFT).
• Synthesis of 10-nm-sized Pt-containing alloy catalysts using in situ methods and infiltration techniques.
• Fabrication and testing of solid oxide electrolysis cells with the novel catalysts.

Main Results:

• Entropy-enhanced alloy catalysts show high Pt utilization, catalytic activity, and thermal stability.
• Computational predictions confirm entropy stabilization of Pt and comparable catalytic properties to pure Pt.
• Reduced Pt loading by 80% with maintained performance, outperforming widely adopted electrode materials.
• Successful scale-up to industrial-sized cells (16 cm2) achieving high current densities (1.6 A/cm2 at 1.5 V, 850 °C).
• Stable operation exceeding 200 hours at 1 A/cm2 and 850 °C with negligible degradation.

Conclusions:

• High-entropy alloy catalysts offer a promising strategy for cost-effective and efficient coelectrolysis.
• The developed catalysts demonstrate excellent performance, stability, and scalability for industrial applications.
• This approach significantly reduces reliance on expensive platinum, paving the way for practical greenhouse gas conversion.