Constructing NiCo/Fe₃O₄ Heteroparticles within MOF-74 for Efficient Oxygen Evolution Reactions

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Metal-organic frameworks (MOFs) are increasingly utilized as precursors for advanced functional materials.
• Oxygen evolution reactions (OER) are critical for energy conversion technologies but require efficient and stable electrocatalysts.

Purpose of the Study:

• To develop a controlled partial pyrolysis strategy for fabricating MOF derivatives with enhanced OER performance.
• To investigate the structural and catalytic properties of NiCo/Fe3O4 heteroparticles embedded within MOF-74.

Main Methods:

• Utilized trimetallic NiCoFe-MOF-74 as a precursor for controlled partial pyrolysis.
• Fabricated NiCo/Fe3O4 heteroparticles within the MOF-74 framework.
• Characterized the material's structure and evaluated its OER performance electrochemically.
• Performed density functional theory (DFT) calculations to understand the catalytic mechanism.

Main Results:

• The synthesized NiCo/Fe3O4/MOF-74 exhibited remarkable OER activity with a low overpotential of 238 mV at 10.0 mA cm-2 and a Tafel slope of 29 mV/dec.
• The partial pyrolysis preserved the MOF framework, facilitating substrate diffusion and nanoparticle formation.
• The material demonstrated superior stability compared to pristine MOFs and fully decomposed derivatives.
• DFT calculations indicated that NiCo enhances Fe3O4's OER activity by stabilizing active oxygen species.

Conclusions:

• Controlled partial pyrolysis of NiCoFe-MOF-74 is an effective strategy to create robust NiCo/Fe3O4/MOF-74 heterostructures for efficient OER.
• The unique nanostructure and synergistic effects between NiCo and Fe3O4 contribute to the enhanced catalytic performance.
• This MOF-derived electrocatalyst shows significant promise for applications in water splitting and other energy conversion systems.