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Synthesis and Characterization of Functionalized Metal-organic Frameworks
Published on: September 5, 2014
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Assembly of a Highly Active Iridium-Based Oxide Oxygen Evolution Reaction Catalyst by Using Metal-Organic Framework
Wei Sun1, Xinlong Tian2, Jianjun Liao1
1Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, College of Ecology and Environment, Hainan University, 58 Renmin Road, Haikou, Hainan 570228, P.R. China.
ACS Applied Materials & Interfaces
|June 5, 2020
Summary
This study introduces a novel Fe-IrO@α-Fe2O3 catalyst for hydrogen production via proton exchange membrane electrolysis. The hybrid catalyst enhances oxygen evolution reaction kinetics, reducing reliance on expensive iridium.
Area of Science:
- Electrochemistry
- Materials Science
- Catalysis
Background:
- Proton exchange membrane (PEM) electrolyzers are crucial for hydrogen production but are limited by expensive iridium catalysts and slow oxygen evolution reaction (OER) kinetics.
- Reducing precious metal loading through highly active catalysts is essential for cost-effective PEM electrolyzers.
Purpose of the Study:
- To develop a novel hybrid catalyst structure (Fe-IrO@α-Fe2O3, Ir@Fe-MF) for enhanced OER activity.
- To investigate the role of iron incorporation into iridium oxide on catalytic performance.
Main Methods:
- A versatile synthesis approach utilizing the self-dissolving properties of Fe-MIL-101 metal-organic framework (MOF) in aqueous conditions.
- Formation of Fe-IrO nanoparticles and α-Fe2O3 support through ion co-precipitation and MOF collapse.
- Characterization using X-ray adsorption spectra (XAS) to analyze electronic structure changes.
Main Results:
- The Ir@Fe-MF-2 hybrid catalyst demonstrated significantly enhanced OER activity with a lower onset potential and Tafel slope.
- An overpotential of only 260 mV was required to reach a current density of 10 mA cm⁻².
- Fe incorporation altered the IrO6 coordination structure and eliminated Ir 5d orbital degeneracy, enhancing OER activity.
Conclusions:
- The study presents a promising strategy for designing efficient OER catalysts using MOF-derived materials.
- The Fe-IrO@α-Fe2O3 hybrid catalyst shows potential for reducing iridium loading in PEM electrolyzers.
- Long-term stability at high current densities in acidic conditions remains a challenge.
