Nanocrystals of a zirconium-based metal-organic framework (Zr-MOF) were grown on carboxylate-functionalized carbon nanotubes (CNT) at room temperature to synthesize electrically conducting Zr-MOF-CNT nanocomposites. To further enable charge transport within the Zr-MOF phase via redox hopping under electrochemical conditions, redox-active manganese sites were then installed in the Zr-MOF and nanocomposites at room temperature by means of the solvothermal deposition in MOFs (SIM) technique. The redox hopping behav- [a]

Graphene quantum dots (GQD) with an average size of 3.1 nm were incorporated into a mesoporous porphyrinic zirconium-based metal−organic framework (MOF) by direct impregnation to render the donor−acceptor charge transfer from GQDs to porphyrinic linkers. The hybrid material still possesses around half porosity of the pristine MOF and shows a 100-fold higher electrical conductivity compared to that of the parent MOF. By utilizing the porphyrinic linkers as catalytically active units, the GQD− MOF material exhibits a better electrochemical sensing activity toward nitrite in aqueous solutions compared to both the pristine MOF and GQD.

In this study, nanocrystals of a cerium-based metal–organic framework (Ce-MOF), Ce-MOF-808, are directly grown on the surface of carboxylic acid-functionalized carbon nanotubes (CNTs) by a facile one-step solvothermal synthesis method. Ce-MOF–CNT nanocomposites with various Ce-MOF-to-CNT ratios are synthesized, and their crystallinity, morphology, porosity, and electrical conductivity are examined. The redox-hopping and electrochemical behaviors of the pristine Ce-MOF in aqueous electrolytes are investigated, suggesting that the pristine Ce-MOF is electrochemically active but possesses a limited charge-transport behavior. As a demonstration, all the Ce-MOF, CNT, and nanocomposites are used as active materials for application in aqueous-based supercapacitors. The capacitive performance of the CNT can be significantly boosted with the help of redox-active Ce-MOF-808 nanocrystals.

In this study, a strategy that can result in the polyaniline (PANI) solely confined within the nanopores of a metal–organic framework (MOF) without forming obvious bulk PANI between MOF crystals is developed. A water‐stable zirconium‐based MOF, UiO‐66‐NH2, is selected as the MOF material. The polymerization of aniline is initiated in the acidic suspension of UiO‐66‐NH2 nanocrystals in the presence of excess poly(sodium 4‐styrenesulfonate) (PSS). Since the pore size of UiO‐66‐NH2 is too small to enable the insertion of the bulky PSS, the quick formation of pore‐confined solid PANI and the slower formation of well dispersed PANI:PSS occur within the MOF crystals and in the bulk solution, respectively. By taking advantage of the resulting homogeneous PANI:PSS polymer solution, the bulk PANI:PSS can be removed from the PANI/UiO‐66‐NH2 solid by successive washing the sample with fresh acidic solutions through centrifugation. As this is the first time reporting the PANI solely confined in the pores of a MOF, as a demonstration, the obtained PANI/UiO‐66‐NH2 composite material is applied as the electrode material for supercapacitors. The PANI/UiO‐66‐NH2 thin films exhibit a pseudocapacitive electrochemical characteristic, and their resulting electrochemical activity and charge‐storage capacities are remarkably higher than those of the bulk PANI thin films.

Silver nanoparticles (NPs) are installed into a porphyrinic zirconium-based metal−organic framework (Zr-MOF), NU-902, through a postsynthetic modification followed by an ion-exchange process. Both the framework-immobilized Ag(I) ions and partially reduced silver NPs confined within the nanopores of NU-902 with the size of around 3 nm are found in the obtained composite. As both the silver NPs and porphyrinic linkers of NU-902 are electrocatalysts for the oxidation of nitrite, the obtained nanocomposite can be applied for the electrochemical nitrite sensor, and the resulting sensing performance is significantly better than that of the pristine porphyrinic Zr-MOF.