Ligand Modulation in Metal-Organic Frameworks Derived Regenerable Oxygen Evolution Electrocatalysts.

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Metal-organic frameworks (MOFs) are promising pre-catalysts for the oxygen evolution reaction (OER).
• Understanding MOF ligand coordination chemistry in reconstructed species is crucial for optimizing OER activity.
• Ligand modulation's impact on catalytic site electronic configurations requires further investigation.

Purpose of the Study:

• To synthesize and characterize a novel MOF composite for OER applications.
• To elucidate the structural and electronic mechanisms underlying the OER performance of MOF-derived active species.
• To investigate the role of ligand modulation in enhancing OER activity and durability.

Main Methods:

• Synthesis of an α-FeOOH coated Ni-catecholate MOF composite (FeOOH@Ni-CAT).
• In situ transformation into a ligand-coordinated γ-NiFeOOH active species during OER.
• Electrochemical characterization of OER performance and durability.
• Theoretical calculations to analyze electronic structures and intermediate adsorption.

Main Results:

• The FeOOH@Ni-CAT composite transforms into a regenerable γ-NiFeOOH active species during OER.
• Ligand modulation significantly enhances adsorption energies of OER intermediates.
• The active species exhibits strengthened bonding states and improved electron delocalization.
• Exceptional OER performance with an ultralow overpotential (180 mV at 10 mA cm⁻²) and long-term durability (384 h).

Conclusions:

• Ligand coordination in reconstructed MOF species is key to high OER performance.
• The FeOOH@Ni-CAT system offers an easily regenerable pre-catalyst for efficient water electrolysis.
• This study advances the understanding of MOF-based pre-catalysts and ligand modulation strategies for OER.