A Novel Approach to MOF-Anchoring Using Cross-Linked Polyaniline and Amine-Functionalized MOF to Generate Polymer-MOF Composites and Functionalized Graphite Electrodes

This investigation explores a novel approach to MOF anchoring using cross-linked polyaniline (PANI-XL) and MIL-125-NH₂ via thermal treatment in THF to engineer an effective material for electrochemical devices. Successful synthesis of these materials was confirmed using FTIR spectroscopy, powder X-ray diffraction, and BET surface area analysis. The PANI-XL@MIL-125-NH₂ composites display altered chemical and microstructural properties upon the thermal treatment in THF. The MIL-125-NH₂ lattice undergoes a mixture of expansion and compression, with an amorphous phase only being introduced upon the introduction of a significant weight fraction of PANI. The surface area of the 1:1 PANI-XL@MIL-125-NH₂ material decreases from 1190.233 m² g^-1 to 354.815 m² g^-1, while the pore volume decreases from 0.5808 cm³ to 0.1475 cm³ after cross-linking. The pore structure reflects the uptake of the polymer, shifting from ultramicropores to a more slit-shaped pore structure. SEM images of the material synthesized on oxidized graphite reveal the MOF present as an easily identifiable phase in the film's morphology. After a film was synthesized onto oxidized graphite, the sheet resistivity measurements of the composites were conducted under air at room temperature using a four-point probe to confirm enhanced conductivity upon thermal treatment. Electrochemical measurements suggest improved performance, increased stability, and enhanced chemical reversibility relative to systems without thermal treatment.