Controlling polyHIPE Surface Properties by Tuning the Hydrophobicity of MOF Particles Stabilizing a Pickering...

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Metal-organic frameworks (MOFs) are promising for greenhouse gas capture.
• Shaping MOFs into hierarchical structures for large-scale fixed-bed processes is challenging.
• Maintaining MOFs' high specific surface area during shaping is critical.

Purpose of the Study:

• To develop an original method for shaping fluorinated Zr MOF (UiO-66(F4)) into hierarchically structured monoliths.
• To enhance the accessibility of MOF particles within the monolith structure.
• To maintain the MOFs' intrinsic properties for effective gas capture applications.

Main Methods:

• Utilized a Pickering emulsion strategy with a fluorinated Zr MOF (UiO-66(F4)) and polyHIPEs (polymers from high internal phase emulsions).
• Modified the MOF's hydrophilic/hydrophobic balance by adsorbing perfluorooctanoic acid (PFOA).
• Polymerized monomers in the continuous phase, followed by paraffin removal to form the monolith.

Main Results:

• Successfully created hierarchically structured monoliths with UiO-66(F4) particles embedded in polymer walls.
• The PFOA modification displaced MOF particles to the interface, reducing pore blocking and increasing accessibility.
• Demonstrated effective N2 and CO2 capture using the hierarchically structured MOF monoliths.

Conclusions:

• The proposed method enables the creation of hierarchically structured MOF monoliths with enhanced particle accessibility.
• This strategy preserves MOF properties and is suitable for fixed-bed gas capture processes.
• The approach is potentially applicable to other MOF materials for various applications.