Deactivation-free Electrochemical Oxygen Evolution Activity of Topological Weyl Semimetal Co3In2S2

Unmet Need: Necessity of robust and efficient electrochemical oxygen evolution reaction for sustainable energy solution

Sustainable oxygen production for medical and industrial applications is one of the prime aims of modern civilization. WSU researchers found an efficient and surprising electrochemical performance of Weyl semimetal Co3In2S2 in its single-crystalline form for oxygen evolution reaction in 1 M KOH. Co3In2S2 single-crystal electrode can produce oxygen at high current densities (300 mA cm^-2 at 1.85 V vs. RHE, without iR-correction) and even in the presence of a surface poisoning agent, bipyridine. The catalyst showed excellent durability without any deactivation for 1000 h at 100 mA cm^-2 current density. This is the first known material, where i) the high-surface-area micro/nano form displays insignificant activity while its bulk form shows high electrochemical activity and ii) stable electrochemical activity is observed in the presence of surface-poisoning ligands.

The Technology A Method for ultra-stable and poison-tolerant oxygen evolution reaction (OER) activity. WSU researchers developed a novel approach for producing pure oxygen for a sustainable solution. Co3In2S2 large single crystals with an electrochemically formed In2O3−x(OH)y surface layer exhibits ultra-stable and poison-tolerant OER activity. When tested in alkaline media (1 M KOH), these electrodes demonstrate exceptional durability, retaining performance over 1000 hours at 100 mA cm⁻², and resistance to surface poisoning by strong ligands such as bipyridine (bpy). The Weyl semimetal single-crystal electrode can produce oxygen at high current densities (300 mA cm^-2 at 1.85 V vs. RHE, without iR-correction). The Weyl semimetal’s, high-surface-area micro/nano form displays insignificant activity while its bulk form shows high electrochemical activity. These properties address critical limitations of current OER catalysts, such as susceptibility to poisoning, high overpotentials, and poor long-term stability.  

Applications:

• Applications in water splitting, hydrogen production, and renewable energy

Advantages:

• Poison Tolerance: Unlike many current catalysts, Co₃In₂S₂/In₂O₃−x(OH)y maintains stable OER activity in the presence of strong surface-poisoning ligands (e.g., KCN, bpy, EDTA). This enables its use in real-world water electrolysis systems where contaminants are common.
• High Durability: Demonstrates over 1000 hours of stable operation at industrially relevant current densities (100 mA cm⁻²) without significant performance degradation, making it a reliable choice for large-scale applications.
• Exceptional Stability: Resists corrosion and surface transformation under extreme conditions, including high temperatures and long-term operational stress.
• Cost-Effective Material: Composed of earth-abundant elements, reducing reliance on expensive and scarce materials like iridium and ruthenium, while maintaining competitive performance.

Enhanced Performance: Exhibits superior catalytic activity, with a relatively low overpotential of 500 mV at 100 mA cm⁻², outperforming traditional RuO₂ and IrO₂ catalysts.

• Environmentally Friendly: Enables clean hydrogen production via water splitting, contributing to sustainable energy solutions.

Patent Information:

A provisional patent application has been filed.