Modulating Host-Guest Interactions in Isoreticular Fe(III)-Doped Co-MOF Precatalysts for Electrocatalytic Oxygen...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Sustainable energy solutions are crucial for addressing environmental challenges and energy crises.
• Electrocatalytic water splitting is a key technology for sustainable energy, but its efficiency is limited by the slow oxygen evolution reaction (OER).

Purpose of the Study:

• To design and synthesize novel cobalt-based metal-organic frameworks (MOFs) with controlled pore sizes for enhanced OER catalysis.
• To investigate the effect of pore size and Fe-doping on the electrocatalytic activity and stability of MOF-derived catalysts for water splitting.

Main Methods:

• Synthesis of two isoreticular cobalt-based MOFs (MOF-74 and MOF-274) with distinct pore sizes.
• Electrochemical activation of Co-MOFs to form Fe-doped CoOOH nanosheets.
• Characterization using X-ray photoelectron spectroscopy (XPS) to analyze electronic interactions.
• Electrocatalytic testing for OER activity and long-term stability.

Main Results:

• MOF-74, with smaller pore sizes, showed enhanced Fe(III) adsorption compared to MOF-274.
• Electrochemical activation yielded Fe-doped CoOOH nanosheets with uniform elemental distribution.
• MOF-74-Fe exhibited superior OER activity with a lower overpotential (288 mV) compared to MOF-274-Fe (357 mV) at 10 mA cm⁻².
• MOF-74-Fe demonstrated excellent long-term stability, retaining 96.9% of its performance over 10 hours.

Conclusions:

• Pore-engineered MOF precatalysts are critical for optimizing electronic modulation and catalytic efficiency in water oxidation.
• Fe-doped CoOOH nanosheets derived from MOF-74 show significant promise as efficient and durable electrocatalysts for sustainable water splitting.