Carbon-Based Nanostructures Vertically Arrayed on Layered Lanthanum Oxycarbonate as Highly Efficient Catalysts for...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Controllable synthesis of metal-organic framework (MOF)-derived carbon nanostructures is crucial for advanced catalysts.
• Oxygen reduction reaction (ORR) catalysts require high activity and durability for energy applications.
• Preventing collapse and aggregation during MOF pyrolysis is key to preserving catalytic properties.

Purpose of the Study:

• To fabricate morphology-controlled carbon-based nanostructures from ZIF-67 grown on La2O2CO3.
• To evaluate the oxygen reduction reaction (ORR) performance of these novel nanostructures.
• To investigate the role of the La2O2CO3 template in enhancing catalytic properties.

Main Methods:

• Epitaxial growth of Co-based zeolitic imidazolate framework (ZIF-67) on layered lanthanum oxycarbonate (La2O2CO3).
• Pyrolysis of the composite material at 800 °C to yield carbon-based nanostructures.
• Electrochemical testing in 0.1 M KOH solution to assess ORR activity and durability.

Main Results:

• Synthesized carbon nanostructures exhibited well-defined dodecahedron morphology and vertical array.
• The MOF-derived carbons showed significantly higher ORR activity and durability compared to pure ZIF-67 derived carbons.
• Performance exceeded that of commercial 20 wt% Pt/C, attributed to increased Co-Nx sites, high surface area, and graphitization.

Conclusions:

• La2O2CO3 serves as an effective structure-oriented template for synthesizing morphology-controlled MOF-derived nanocarbons.
• This strategy enhances the catalytic activity and durability for the oxygen reduction reaction (ORR).
• The approach offers a promising route for developing high-performance catalysts for energy conversion and storage devices.