Work-function-induced Interfacial Built-in Electric Fields in Os-OsSe₂ Heterostructures for Active Acidic and...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Optimizing electrocatalysts for hydrogen evolution reaction (HER) is crucial for clean energy.
• Osmium (Os) and osmium diselenide (OsSe2) have distinct electronic properties affecting catalytic activity.
• Achieving a balance between strong and weak adsorbents is key to enhancing HER performance.

Purpose of the Study:

• To theoretically design and experimentally synthesize Os-OsSe2 heterostructures.
• To investigate the work function (WF) and electronic state balance in the heterostructure.
• To evaluate the hydrogen evolution reaction (HER) activity and potential applications in solar-to-hydrogen devices.

Main Methods:

• Theoretical calculations to predict the electronic properties and HER activity.
• Molten salt method for the synthesis of Os-OsSe2 heterostructures.
• In-depth structural characterization and electrochemical performance testing in acidic and alkaline media.

Main Results:

• Os-OsSe2 heterostructures achieve a neutralized work function, balancing electronic states between Os and OsSe2.
• The heterostructure significantly reduces the thermodynamic energy barrier and accelerates the kinetics of the HER.
• Os-OsSe2 exhibits ultra-low overpotentials for HER (26 mV in acidic, 23 mV in alkaline media), outperforming commercial Pt catalysts.

Conclusions:

• The Os-OsSe2 heterostructure provides a new model for rational design of efficient HER electrocatalysts.
• Charge balance effect in heterostructures is a viable strategy to optimize catalytic activity.
• The developed catalyst shows promise for practical applications in solar-to-hydrogen energy conversion.