Dual Lewis Acid Sites Enabling Passivation-Resistant Sulfur Oxidation Coupled Hydrogen Evolution Reaction

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Coupling sulfide oxidation reaction (SOR) with hydrogen evolution reaction (HER) offers energy-efficient hydrogen production and sulfide wastewater treatment.
• Transition metal catalysts face challenges like sluggish kinetics and sulfur passivation at high current densities.

Purpose of the Study:

• To design a novel catalyst for efficient and stable hydrogen production and sulfide oxidation.
• To investigate the mechanism of enhanced catalytic activity at the atomic level.

Main Methods:

• Fabrication of oxygen-coordinated iridium single-atom anchored on a nickel surface (Ir1O-Ni/C).
• Electrochemical characterization to evaluate HER and SOR performance.
• Mechanistic studies using computational analysis to understand catalytic pathways.

Main Results:

• The Ir1O-Ni/C catalyst demonstrated excellent HER activity (1 A cm-2 at 280 mV overpotential) and SOR performance (0.67 V for 500 mA cm-2).
• The catalyst exhibited stable operation for over 50 hours in a flow cell.
• Dual Lewis acid sites and electron-deficient nickel were identified as key factors for suppressing sulfur accumulation and enhancing kinetics.

Conclusions:

• The developed Ir1O-Ni/C catalyst effectively addresses challenges in SOR-HER coupling, showing high efficiency and stability.
• The atomic-level design strategy provides insights for developing advanced bifunctional catalysts for energy and environmental applications.