A tailored double perovskite nanofiber catalyst enables ultrafast oxygen evolution

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Rechargeable metal-air batteries and water splitting are crucial for sustainable energy.
• Commercialization is limited by the lack of efficient and stable oxygen evolution reaction (OER) catalysts.
• Developing cost-effective OER catalysts is a key challenge.

Purpose of the Study:

• To design and synthesize a highly efficient and robust catalyst for the oxygen evolution reaction.
• To investigate the impact of composition and morphology on catalytic activity.
• To explore the underlying mechanisms for enhanced OER performance.

Main Methods:

• Rational design and synthesis of a double perovskite PrBa_0.5Sr_0.5Co_1.5Fe_0.5O_5+δ nanofiber.
• Electrochemical measurements to evaluate catalytic activity.
• First-principles calculations to understand intrinsic activity.
• Chemical titration and electron energy-loss spectroscopy to analyze surface properties.

Main Results:

• Co-doping with strontium and iron significantly enhanced the intrinsic activity of the PrBaCo₂O_5+δ catalyst by approximately 4.7 times.
• Nanofiber morphology, with diameters around 20 nm, resulted in a remarkable 20-fold increase in mass activity.
• Enhanced activity is attributed to increased surface area and a favorable e_g electron filling due to partial surface reduction.

Conclusions:

• The developed double perovskite nanofiber is a highly efficient and robust catalyst for the oxygen evolution reaction.
• Compositional tuning (Co-doping) and morphological control (nanofibers) are effective strategies to improve OER catalyst performance.
• The study provides insights into the structure-activity relationships for perovskite-based OER catalysts.