Electrically Conducting Nanocomposites of Carbon Nanotubes and Metal‐Organic Frameworks with Strong Interactions between the two Components

Abstract

Highly integrated nanocomposites of Zr‐based metal‐organic frameworks (MOFs) of the UiO‐66 class and multi‐wall carbon nanotubes (MWCNTs) are prepared by direct crystallization of MOFs in the presence of CNTs. Powder samples with homogeneously distributed and strongly intergrown nanotubes and nanoparticles are obtained. Growth of the MOFs in the presence of CNTs deposited on glass slides yields open or compact coatings of the nanocomposites. The materials combine the high porosity and versatility of MOFs with the high electrical conductivities of CNTs. Upon increasing the amount of CNTs in the synthesis, the electrical conductivity shows a clear percolation behavior. Even with small amounts of CNTs, high conductivities are observed. SEM and TEM pictures show the strong intergrowth between the CNTs and the MOF nanoparticles. Crystallization times are shorter in the presence of CNTs, and CNTs run centrally through the MOF crystals. These facts indicate that the CNTs serve as heterogeneous nucleation centers for the formation of MOF nanocrystals. Sensing experiments performed on the coatings show significant changes in the electrical conductivities of the nanocomposite materials in the presence of different analytes, which are also discernable from the changes observed on bare CNTs. This is further proof for the close interaction between the components of the nanocomposites.

Cerium-Based Metal–Organic Framework Nanocrystals Interconnected by Carbon Nanotubes for Boosting Electrochemical Capacitor Performance

“…The highly porous MOF nanocrystals can provide a high density of electrochemically active sites that rely on the hopping-based charge transport to move electrons between them, and another electrically conducting material, for example, nanocarbons, can provide a facile electronic conduction between MOF crystals. Indeed, such nanocomposites composed of water-stable zirconium- or hafnium-based MOFs and nanocarbons have been reported previously, − and some of them have been applied for electrochemical applications. ,, …”

Size Discrimination of Carbohydrates via Conductive Carbon Nanotube@Metal Organic Framework Composites

“…Several composites using multiwalled carbon nanotubes (MWCNT) have also been made for applications in water remediation. , Both traditional electrochemical sensing applications as well as electrocatalytic materials for OER/ORR /HER have been realized. Chemiresistive sensing for common VOCs have been another common target for this class of materials. , Gas storage and separation for CO 2 , and H 2 − have been other areas of study. Other energy storage applications including supercapacitors have seen initial exploration .…”

“…Chemiresistive sensing for common VOCs have been another common target for this class of materials. 50,51 Gas storage and separation for CO 2 52,53 and H 2 54−56 have been other areas of study. Other energy storage applications including supercapacitors have seen initial exploration.…”

Zirconium-Based Metal–Organic Framework Nanocomposites Containing Dimensionally Distinct Nanocarbons for Pseudocapacitors

“…One alternative approach to improve the sluggish redox hopping and facilitate the interparticle charge transport in Zr-MOFs is to design MOF-based nanocomposites, which contain another electrically conductive component to connect different MOF crystals . For example, a variety of conductive nanocarbons such as one-dimensional (1D) carbon nanotubes (CNTs) − and two-dimensional (2D) graphene or graphene oxide − have been utilized to design electrically conductive MOF-based composites. In our recent study, it has been found that by integrating the redox hopping in Zr-MOF nanocrystals and the electron conduction in 1D CNTs bridging between MOF crystals, the resulting electrochemical performance can be improved significantly .…”