Improving the Oxygen Evolution Reaction: Exsolved Cobalt Nanoparticles on Titanate Perovskite Catalyst

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Perovskites are tunable catalysts for oxygen evolution reaction (OER) but often suffer from low atom utilization efficiency due to large particle sizes.
• Improving mass activity and atom utilization is crucial for efficient OER catalysis.

Purpose of the Study:

• To enhance the atom utilization efficiency and OER performance of perovskite catalysts by exsolving cobalt nanoparticles.
• To investigate the catalytic activity and stability of the exsolved cobalt nanoparticle perovskite catalyst.

Main Methods:

• Synthesis of La_0.2+2x Ca_0.7-2x Ti_1-x Co_x O₃ perovskite.
• Exsolution of cobalt nanoparticles via reduction in H₂/N₂ atmosphere.
• Electrochemical characterization including OER performance testing and electrochemical impedance spectroscopy (EIS).
• Accelerated durability testing (10 h electrolysis, 1000 CV cycles).

Main Results:

• The exsolved cobalt nanoparticle catalyst (R-LCTCo0.11) achieved a mass activity of ≈1700 mA mg^-1 at 450 mV overpotential, significantly higher than parent perovskite and benchmark RuO₂.
• R-LCTCo0.11 exhibited the lowest charge transfer resistance (58 Ω), indicating superior catalytic and kinetic activity.
• The catalyst demonstrated high stability over 10 hours of electrolysis and 1000 cyclic voltammetry cycles.

Conclusions:

• Nanoparticle exsolution from doped perovskites is an effective strategy to boost atom utilization efficiency for OER.
• The R-LCTCo0.11 catalyst presents a promising alternative for efficient and stable oxygen evolution catalysis.