Amorphous/Crystalline Interface of LDH-MOF Heterostructure Enables Efficient Oxygen Evolution Reaction

Area of Science:

• Electrochemistry
• Materials Science
• Sustainable Energy

Background:

• Efficient oxygen evolution reaction (OER) electrocatalysts are crucial for sustainable hydrogen production.
• Layered double hydroxides (LDHs) and metal-organic frameworks (MOFs) show promise but face challenges like poor conductivity and instability.
• Noble metal catalysts are effective but costly and scarce.

Purpose of the Study:

• To develop a novel hierarchical amorphous/crystalline heterostructure for improved OER performance.
• To investigate the interfacial effects and charge transfer mechanisms in the designed electrocatalyst.
• To provide insights into optimizing OER pathways for efficient water splitting.

Main Methods:

• Fabrication of a NiFe-LDH@NiFe-MOF heterostructure via electrodeposition.
• Characterization using techniques including differential electrochemical mass spectrometry (DEMS).
• Electrochemical testing in alkaline media to evaluate OER performance and durability.

Main Results:

• The NiFe-LDH@NiFe-MOF/NF catalyst exhibited a low overpotential of 257 mV at 10 mA cm⁻² and a Tafel slope of 56 mV dec⁻¹.
• DEMS revealed lattice oxygen participation, indicating a shift to the more efficient lattice oxygen oxidation mechanism (LOM).
• The catalyst demonstrated over 100 hours of durability and high selectivity in alkaline seawater.

Conclusions:

• The hierarchical LDH-on-MOF structure effectively prevents aggregation and enhances conductivity.
• Interfacial electronic engineering optimizes metal coordination, activating lattice oxygen for OER.
• This strategy offers a pathway to high-performance, durable, and cost-effective electrocatalysts for water splitting.