Screening highly active perovskites for hydrogen-evolving reaction via unifying ionic electronegativity descriptor.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Efficient electrocatalysts are crucial for energy conversion technologies like water splitting.
• ABO3-δ perovskites offer diverse structures but lack activity descriptors for the hydrogen evolution reaction (HER).

Purpose of the Study:

• To introduce and validate A-site ionic electronegativity (AIE) as a predictive descriptor for HER activity in cobalt-based perovskites.
• To identify high-performance perovskite electrocatalysts for water splitting.

Main Methods:

• Screening of 13 cobalt-based perovskites using AIE as a descriptor.
• Electrochemical testing of predicted optimal perovskite compositions.
• X-ray absorption and computational studies to elucidate structure-activity relationships.

Main Results:

• AIE demonstrated the best volcano trend for HER activity compared to other descriptors.
• (Gd0.5La0.5)BaCo2O5.5+δ exhibited superior activity and stability over Pt/C.
• Optimal HER activity correlated with moderate AIE (~2.33) and specific electronic states at the B-site.

Conclusions:

• AIE is an effective unifying descriptor for designing HER electrocatalysts.
• The developed perovskite material shows significant potential for efficient water splitting.
• Understanding electronic structure is key to optimizing perovskite electrocatalyst performance.