In Situ-Generated Hollow CoFe-LDH/Co-MOF Heterostructure Nanorod Arrays for Oxygen Evolution Reaction

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Heterostructures are effective for enhancing electrocatalytic activity in hybrid materials.
• Developing efficient, non-noble metal electrocatalysts is crucial for water splitting technologies.
• Metal-organic frameworks (MOFs) and layered double hydroxides (LDHs) show promise in catalysis.

Purpose of the Study:

• To synthesize and characterize CoFe-LDH/Co-MOF hollow heterostructure nanorod arrays.
• To evaluate the electrocatalytic performance of the synthesized material for the oxygen evolution reaction (OER).
• To investigate the synergistic effects and electronic structure modifications contributing to enhanced catalytic activity.

Main Methods:

• Synthesis of Co-MOF hollow nanorod arrays on nickel foam via solvothermal methods.
• Electrodeposition of CoFe-LDH onto Co-MOF nanorod arrays to form heterostructures.
• Electrocatalytic testing for OER, including overpotential and stability measurements.
• Density functional theory (DFT) calculations to analyze electronic structure and reaction mechanisms.

Main Results:

• Successfully synthesized CoFe-LDH/Co-MOF hollow heterostructure nanorod arrays retaining the nanorod morphology.
• Optimized CoFe-LDH/Co-MOF exhibited excellent OER performance with ultralow overpotentials (215 mV at 10 mA cm⁻²) and remarkable stability (220 h).
• DFT calculations confirmed synergistic effects between Co-MOF and CoFe-LDH, reducing the rate-determining step's free energy and enhancing charge transfer.

Conclusions:

• The CoFe-LDH/Co-MOF hollow heterostructure nanorod arrays represent a highly efficient non-noble metal electrocatalyst for OER.
• The MOF component plays a key role in tuning the electronic structure and facilitating active site creation.
• This study provides a strong experimental and theoretical foundation for designing advanced heterostructure catalysts for efficient water splitting.