Bimetal Modulation Stabilizing a Metallic Heterostructure for Efficient Overall Water Splitting at Large Current...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Alkaline water splitting for hydrogen production faces challenges with slow charge transfer kinetics and catalyst instability at high current densities.
• Non-noble metal catalysts often show limited activity below industrially required current densities (>500 mA cm^-2).

Purpose of the Study:

• To design a sulfide-based metallic heterostructure catalyst for efficient large-current alkaline water splitting.
• To address the limitations of existing catalysts by enhancing charge transfer and stability.

Main Methods:

• Fabrication of a metallic heterostructure by incorporating Molybdenum (Mo) and Nickel (Ni) into a sulfide-based material.
• Modulation of the electronic structure through phase transition and interfacial defects.
• In situ epitaxial growth of a bifunctional Nickel-based catalyst on a metallic Molybdenum sulfide (Mo₂ S₃) base.

Main Results:

• The Mo₂ S₃ @NiMo₃ S₄ heterostructure achieved an ultralow voltage of 1.672 V at a high current density of 1000 mA cm^-2.
• Demonstrated excellent stability with approximately 100% retention over 100 hours of operation.
• Outperformed commercial Ruthenium dioxide (RuO₂) and Platinum on Carbon (Pt/C) catalysts.

Conclusions:

• The designed metallic heterostructure effectively facilitates charge transfer for rapid hydrogen generation.
• Synergistic effects from phase and interface electronic modulation are key to the catalyst's superior performance.
• This work provides insights into designing advanced catalysts for industrial-scale water splitting.