Active Site Customizing of Metal-Organic Materials for Highly Efficient Oxygen Evolution

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Understanding the active sites in multi-component metal-organic frameworks (MOFs) is crucial for advancing the oxygen evolution reaction (OER).
• The precise mechanism linking active sites and catalytic activity in MOFs for OER remains largely unclear.

Purpose of the Study:

• To elucidate the mechanism of the oxygen evolution reaction (OER) in multi-component metal-organic frameworks (MOFs).
• To investigate the correlation between active sites and catalytic activity by combining theoretical predictions and experimental validation.

Main Methods:

• Utilized Density Functional Theory (DFT) to predict the electronic properties and adsorption energies of OER intermediates.
• Synthesized Cobalt-based MOFs doped with high-valence Molybdenum (Mo) on Nickel foam (NF) substrates.
• Performed quantitative studies on composition-dependent OER performance and long-term stability.

Main Results:

• DFT predicted that co-modulation by Molybdenum (Mo) and Cobalt (Co) enhances MOF conductance and optimizes OER intermediate adsorption.
• The optimized Co/Mo ratio of 5:1 in MOFs demonstrated exceptional OER activity, with an overpotential of 324 mV at 100 mA cm⁻² and a Tafel slope of 96.07 mV dec⁻¹.
• The developed MOF catalysts exhibited excellent stability, maintaining performance for 200 hours at 100 mA cm⁻², outperforming commercial RuO₂/NF benchmarks.

Conclusions:

• The study successfully demonstrated a pathway for tailoring MOF active sites for enhanced OER catalysis.
• The findings highlight the significant role of Mo-Co co-modulation in improving OER efficiency and stability.
• This work provides valuable insights into designing high-performance electrocatalysts for the oxygen evolution reaction.