Synergistic Ni Single Atoms/Nanoparticles on CeO₂ for High-Performance and Durable SOFC Hydrogen Electrodes

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Degradation of Ni-based anodes in solid oxide fuel cells (SOFCs) at high temperatures limits performance and lifespan.
• The three-phase boundary in SOFC anodes is crucial for hydrogen oxidation reaction (HOR) but susceptible to degradation.

Purpose of the Study:

• To develop a stable and highly active oxide-based anode for SOFCs.
• To investigate the synergistic effects of Ni single atoms (SAs) and nanoparticles (NPs) on anode performance.

Main Methods:

• Synthesis of a Ni single atom and nanoparticle decorated ceria anode (e-Ni/CeO2-5%) using metal-organic frameworks (MOFs) and exsolution.
• Characterization of the anode material's structure and electrochemical properties.

Main Results:

• The e-Ni/CeO2-5% anode achieved a peak power density of 1.46 W cm⁻² at 800°C.
• The anode demonstrated excellent durability with negligible voltage degradation (< 0.005% h⁻¹) over 500 hours.
• Ni SAs were found to stabilize Ni NPs and generate oxygen vacancies, enhancing catalytic activity.

Conclusions:

• The engineered Ni SAs/NPs decorated CeO2 anode offers superior HOR catalytic activity and long-term stability for SOFCs.
• The combination of MOF templating and exsolution is an effective strategy for developing advanced SOFC anode materials.