Highly Exposed Ultra-Small High-Entropy Sulfides with d-p Orbital Hybridization for Efficient Oxygen Evolution

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• The activity-stability trade-off is a major challenge in oxygen evolution electrocatalysts.
• Precise control over electronic structure and nanoscale geometry is key to overcoming this limitation.

Purpose of the Study:

• To design and investigate ultra-small high-entropy sulfides (HES) confined in porous carbon nanofibers for enhanced oxygen evolution reaction (OER) performance.
• To explore the synergistic effects of d-p orbital hybridization and nanoconfinement on electrocatalyst properties.

Main Methods:

• Synthesis of HES confined in porous carbon nanofibers.
• X-ray absorption spectroscopy (XAS) for electronic structure analysis.
• Density functional theory (DFT) calculations for orbital interaction and charge redistribution.
• Electrochemical testing to evaluate OER activity and durability.

Main Results:

• Achieved HES with an average size of 5.2 nm, exhibiting d-p orbital hybridization.
• DFT and XAS confirmed orbital hybridization, leading to a d-band center shift and enhanced electron-donating capability.
• Optimized adsorption of OER intermediates (e.g., *OH, *O, *OOH).
• Demonstrated exceptional OER performance: 200 mV overpotential at 10 mA cm⁻² and stable operation for 300 hours.

Conclusions:

• A dual optimization strategy combining orbital hybridization and nanoconfinement engineering effectively breaks the activity-stability trade-off in OER electrocatalysts.
• The designed HES material offers a promising new approach for advanced electrocatalyst design in energy conversion technologies.