Engineering iridium-based metal organic frameworks towards electrocatalytic water oxidation

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Homogeneous water oxidation catalysts often suffer from poor stability due to structure collapse and harsh reaction conditions.
• Developing robust and efficient catalysts for water oxidation is crucial for energy conversion technologies.
• Metal-organic frameworks (MOFs) offer a promising platform for creating stable heterogeneous catalysts.

Purpose of the Study:

• To design and synthesize a stable and efficient heterogeneous water oxidation catalyst.
• To investigate the electrocatalytic performance of iridium-doped MOFs for the oxygen evolution reaction.
• To explore the potential of MOFs in protecting molecular catalysts and enhancing electron transfer.

Main Methods:

• Functionalization of bipyridine-incorporated MOFs with [IrCp*Cl(μ-Cl)]2 complexes to create Ir-doped MOFs.
• Immobilization of the Ir-doped MOFs onto a glassy carbon electrode surface.
• Electrochemical characterization to evaluate catalytic activity, onset potential, and Faradaic efficiency for water oxidation.

Main Results:

• The synthesized Ir-doped MOFs exhibited a stable, porous heterogeneous structure.
• Optimized conditions yielded an onset potential of 0.87 V vs. NHE for the oxygen evolution reaction.
• The catalyst achieved a high Faradaic efficiency of 99% and maintained activity for over 3600 seconds.

Conclusions:

• The Ir-doped MOFs demonstrate excellent electrochemical performance as water oxidation catalysts.
• The MOF structure provides stability to the molecular catalyst and facilitates efficient electron transfer.
• This work highlights the potential of MOFs as robust supports for electrocatalytic applications.