Metal-Organic Framework-Spinel Fe-ZIF-8@NiAl₂O₄ Heterostructures Enabling Efficient and Durable Alkaline Water...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Spinel metal oxides like NiAl₂O₄ are promising electrocatalysts for water splitting.
• Challenges include low surface area, poor conductivity, and sluggish kinetics, limiting their practical application.

Purpose of the Study:

• To develop a bifunctional MOF-spinel heterostructured catalyst (Fe-ZIF-8@NiAl₂O₄) for efficient alkaline water splitting.
• To investigate the synergistic effects between MOF and spinel components for enhanced catalytic activity and durability.

Main Methods:

• Solvothermal synthesis of NiAl₂O₄ spinel nanoparticles.
• Integration of NiAl₂O₄ with iron-doped ZIF-8 to form a heterostructure without post-synthetic pyrolysis.
• Electrochemical characterization of the Fe-ZIF-8@NiAl₂O₄ catalyst for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER).

Main Results:

• The Fe-ZIF-8@NiAl₂O₄ composite exhibited low overpotentials: 231 mV for OER and 109 mV for HER at 10 mA cm^-2.
• Synergistic Fe-Ni interfacial interactions enhanced electronic redistribution and charge transfer kinetics.
• The catalyst demonstrated excellent durability and stable overall water splitting performance with beneficial surface reconstruction.

Conclusions:

• MOF hybridization is an effective strategy to activate Al-based spinel oxides for electrocatalysis.
• The Fe-ZIF-8@NiAl₂O₄ heterostructure provides a promising pathway for developing cost-effective, noble-metal-free electrocatalysts.
• This research offers practical design insights for sustainable hydrogen production via water splitting.