Amorphous Oxysulfide Reconstructed from Spinel NiCo₂ S₄ for Efficient Water Oxidation

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Effective electrocatalysts for oxygen evolution reaction (OER) are critical for efficient green hydrogen production.
• Spinel cobalt-based oxides are promising OER electrocatalysts, but their performance often requires improvement.
• Current research primarily focuses on cation modification, leaving anionic regulation underexplored.

Purpose of the Study:

• To investigate the impact of anionic regulation, specifically sulfur (S) anion substitution, on the OER performance of spinel cobalt oxides.
• To explore the structural and electronic properties of sulfur-substituted spinel oxides under OER conditions.
• To develop a novel strategy for designing robust and easily prepared spinel oxide electrocatalysts.

Main Methods:

• Anionic regulation via sulfur substitution: replacing oxygen with sulfur in NiCo2O4 to form NiCo2S4.
• Electrocatalytic testing under alkaline conditions to evaluate OER performance.
• Structural and electronic characterization to understand the active phase formation and properties.

Main Results:

• Sulfur substitution in NiCo2O4 to form NiCo2S4 resulted in impressive OER performance in alkaline media.
• The S substitution induced a sub-stable spinel structure that reconstructs into an active amorphous oxysulfide under OER conditions.
• The resulting hetero-anionic amorphous oxysulfide exhibited a tuned electronic structure and high electrocatalytic activity.

Conclusions:

• Anionic regulation through sulfur substitution is a viable strategy to enhance OER electrocatalyst performance.
• The in-situ reconstruction to an amorphous oxysulfide active phase is key to the improved catalytic activity.
• This approach offers a promising route for developing robust and easily prepared spinel oxide-based OER electrocatalysts for green hydrogen production.