A-Site High-Entropy Strategy Activated Cobalt-Based Perovskite Oxides for Hydrogen and Oxygen Evolution Reactions.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Perovskite oxides are promising catalysts for green hydrogen generation via water electrolysis.
• Current limitations include insufficient bifunctional efficiency for hydrogen evolution (HER) and oxygen evolution (OER) reactions.
• Developing efficient and stable perovskite catalysts is crucial for large-scale applications.

Purpose of the Study:

• To synthesize and characterize a novel A-site high-entropy perovskite oxide, (LaSmPrBaSr)0.2CoO3 (LSmPBSC).
• To evaluate the bifunctional electrocatalytic performance of LSmPBSC for HER and OER.
• To assess the long-term stability of LSmPBSC in water electrolysis.

Main Methods:

• Fabrication of LSmPBSC using a scalable glycine combustion process.
• Electrochemical characterization of HER and OER performance in 1.0 M KOH.
• Assessment of long-term stability for HER and OER at high current densities.
• Testing of an integrated two-electrode electrolyzer for total water splitting.

Main Results:

• Phase-pure LSmPBSC was synthesized without elemental phase segregation.
• LSmPBSC exhibited low overpotentials: 237 mV for HER and 336 mV for OER at 10 mA cm-2.
• Exceptional long-term stability was observed for both HER and OER over 500 hours at 100 mA cm-2.
• The integrated electrolyzer achieved 10 mA cm-2 at 1.78 V with 350 hours of stable operation.

Conclusions:

• The A-site high-entropy strategy effectively enhances the bifunctional electrocatalytic activity and durability of perovskite oxides.
• LSmPBSC presents a viable and efficient catalyst for large-scale green hydrogen production through water electrolysis.
• This approach offers a pathway for designing advanced perovskite catalysts for energy applications.