An Active Catalyst for Efficient High-Temperature Water Splitting on Oxygen-Ion-Based Solid Oxide Electrolysis Cells.

Area of Science:

• Electrochemistry
• Materials Science
• Renewable Energy

Background:

• High-temperature solid oxide electrolysis cells (SOECs) are efficient for hydrogen production.
• Current SOECs face challenges with fuel electrode catalytic activity and stability.
• Oxygen-ion conducting electrolytes are key to SOEC efficiency.

Purpose of the Study:

• To enhance the catalytic activity and durability of Ni-YSZ fuel electrodes for water splitting in SOECs.
• To investigate the effect of Pr_0.975Sm_0.025O_2-δ (PSO) nanoparticle surface catalysts.
• To improve hydrogen production efficiency and stability in SOECs.

Main Methods:

• Fabrication of Ni-YSZ fuel electrodes modified with PSO nanoparticles.
• Electrochemical characterization including fuel cell mode performance and water splitting tests.
• Material analysis using X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS) with distribution of relaxation times (DRT).

Main Results:

• PSO-modified Ni-YSZ electrodes demonstrated significantly enhanced catalytic activity and durability.
• Achieved a peak power density of 1.27 W cm^-2 in fuel cell mode.
• Demonstrated excellent stability at -0.5 A cm^-2 for over 200 hours at 700 °C with 50% H₂O.
• Achieved a hydrogen production rate of 3.48 mL min^-1 cm^-2 with nearly 100% Faradaic efficiency at 700 °C.

Conclusions:

• The Pr³⁺/Pr⁴⁺ redox couple and oxygen vacancies in PSO contribute to improved catalytic performance.
• The developed PSO-modified Ni-YSZ electrodes offer a promising solution for efficient and stable hydrogen production via SOECs.
• This advancement addresses key challenges in SOEC technology for renewable hydrogen generation.