Constructing Dual-Phase Co₉S₈-CoMo₂S₄ Heterostructure as an Efficient Trifunctional Electrocatalyst for Oxygen...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Developing efficient trifunctional electrocatalysts for oxygen reduction (ORR), oxygen evolution (OER), and hydrogen evolution (HER) is crucial for rechargeable zinc-air batteries and water-splitting.
• Transition metal-based heterostructures are a promising strategy for creating advanced electrocatalytic materials.

Purpose of the Study:

• To synthesize and investigate a novel dual-phase Co9S8-CoMo2S4 heterostructure on a porous N, S-codoped carbon substrate (Co9S8-CoMo2S4/NSC) as a trifunctional electrocatalyst.
• To evaluate the electrocatalytic performance of the synthesized material for ORR, OER, and HER, and its application in zinc-air batteries and water-splitting.

Main Methods:

• One-pot synthesis of the Co9S8-CoMo2S4/NSC heterostructure.
• Electrochemical characterization including cyclic voltammetry and polarization curves to assess ORR, OER, and HER activity.
• Fabrication and testing of zinc-air batteries and water-splitting devices utilizing the synthesized electrocatalyst.

Main Results:

• The optimized Co9S8-CoMo2S4/NSC2 catalyst demonstrated excellent ORR activity with a half-wave potential of 0.86 V (vs. RHE).
• Low overpotentials of 280 mV for OER and 89 mV for HER at 10 mA cm−2 were achieved, outperforming many existing trifunctional catalysts.
• The derived zinc-air battery exhibited a high open-circuit voltage (1.41 V), large capacity (804 mAh g−1), and remarkable stability (97 h).
• The zinc-air battery could effectively drive a water-splitting device in series.

Conclusions:

• The dual-phase Co9S8-CoMo2S4 heterostructure on NSC is a highly effective trifunctional electrocatalyst.
• The synergistic effect between the dual phases and the porous carbon substrate enhances catalytic activity and charge transfer.
• This material shows significant potential for advanced energy storage and conversion applications, including rechargeable zinc-air batteries and water-splitting.