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Macro/Microporous Covalent Organic Frameworks for Efficient Electrocatalysis.

Xiaojia Zhao1, Pradip Pachfule1, Shuang Li1

  • 1Department of Chemistry, Division of Functional Materials , Technische Universität Berlin , Hardenbergstraße 40 , 10623 Berlin , Germany.

Journal of the American Chemical Society
|March 28, 2019
PubMed
Summary
This summary is machine-generated.

We developed a facile strategy to create crystalline covalent organic frameworks (COFs) with hierarchical macro-microporous structures. These novel COFs demonstrate enhanced oxygen evolution reaction (OER) activity due to improved mass transport and accessible active sites.

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Area of Science:

  • Materials Science
  • Nanotechnology
  • Catalysis

Background:

  • Covalent organic frameworks (COFs) offer robust structures, low density, and high surface area for diverse applications.
  • Typically, COFs exhibit microporosity, limiting mass transport for certain applications.
  • Hierarchical pore structures combining micro- and macropores are ideal for enhanced mass transport.

Purpose of the Study:

  • To develop a facile strategy for fabricating crystalline COFs with inherent microporosity and tunable macroporosity.
  • To synthesize and characterize β-ketoenamine-based COFs with interconnected macro-microporous structures.
  • To investigate the catalytic activity of metal-coordinated hierarchical COFs for the oxygen evolution reaction (OER).

Main Methods:

  • Fabrication of crystalline COFs using a template-induced method to create hierarchical pore structures.
  • Incorporation of bipyridine moieties into the COF backbone for metal coordination.
  • Synthesis of macro-TpBpy-Co by coordinating Co2+ within the hierarchical pore structure.

Main Results:

  • Successfully synthesized various β-ketoenamine-based COFs with interconnected macro-microporous structures.
  • The synthesized macroporous COFs maintained high crystallinity and high specific surface area.
  • The resulting macro-TpBpy-Co exhibited significantly improved OER activity (380 mV at 10 mA/cm2) compared to purely microporous COFs.

Conclusions:

  • The developed facile strategy enables the fabrication of crystalline COFs with tunable hierarchical pore structures.
  • Hierarchical porosity in COFs enhances mass transport properties, crucial for catalytic applications.
  • The macro-TpBpy-Co catalyst demonstrates high OER activity, attributed to improved mass diffusion and accessible active sites.