6 research outputs found
Tailoring the Adsorption and Reaction Chemistry of the Metal–Organic Frameworks UiO-66, UiO-66-NH<sub>2</sub>, and HKUST‑1 via the Incorporation of Molecular Guests
Metal–organic
frameworks (MOFs) are versatile materials
highly regarded for their porous nature. Depending on the synthetic
method, various guest molecules may remain in the pores or can be
systematically loaded for various reasons. Herein, we present a study
that explores the effect of guest molecules on the adsorption and
reactivity of the MOF in both the gas phase and solution. The differences
between guest molecule interactions and the subsequent effects on
their activity are described for each system. Interestingly, different
effects are observed and described in detail for each class of guest
molecules studied. We determine that there is a strong effect of alcohols
with the secondary building unit of UiO MOFs, while Lewis bases have
an effect on the reactivity of the −NH<sub>2</sub> group in
UiO-66-NH<sub>2</sub> and adsorption by the coordinatively unsaturated
copper sites in HKUST-1. These effects must be considered when determining
synthesis and activation methods of MOFs toward various applications
Facile Synthesis and Direct Activation of Zirconium Based Metal–Organic Frameworks from Acetone
In recent years much emphasis has
been placed on the synthesis
of highly novel metal–organic frameworks (MOFs) with general
disregard to development of sustainable synthesis techniques. A novel
synthesis of UiO-66 and UiO-66-NH<sub>2</sub>, two highly stable MOFs
that have shown much promise in the area of catalysis and reactive
removal of small molecules, from acetone is demonstrated here. Using
this method, the MOFs can be activated by simple heating under vacuum
without the need for solvent exchange, which can be a timely processing
step that requires the use of large amounts of solvent. The activity
of the series of MOFs synthesized at various temperatures was determined
by the rate of hydrolysis of methyl paraoxon and the reactive capacity
of UiO-66-NH<sub>2</sub> with chlorine gas. Direct correlations were
observed between synthesis temperature, crystallinity, BET surface
area, and activity of the MOFs
Direct Surface Growth Of UIO-66-NH<sub>2</sub> on Polyacrylonitrile Nanofibers for Efficient Toxic Chemical Removal
Direct solvothermal
growth of the metal–organic framework
(MOF) UiO-66-NH<sub>2</sub> on polymer surface was successfully demonstrated.
By using acetone as the solvent for synthesis instead of <i>N</i>,<i>N</i>-dimethylformamide, polymers like polyacrylonitrile
(PAN) can be used directly in the solvothermal synthesis step to grow
MOF on the polymer surface. We use X-ray diffraction and FT-IR to
confirm our method produces crystalline UiO-66-NH2 on the surface
of electrospun PAN nanofibers. Characterization of this type of composite
revealed up to 50 wt % MOF loading according to nitrogen isotherms.
Since the MOFs are located on the surface of the polymer fibers, the
composites are capable of high loadings of chlorine gas. Compared
to electrospun composites made with preformed UiO-66-NH<sub>2</sub>, the in situ method is a simple alternative that produces composites
with higher MOF loading
Polymer–Metal–Organic Frameworks (polyMOFs) as Water Tolerant Materials for Selective Carbon Dioxide Separations
Recently,
polymer–metal–organic frameworks (polyMOFs)
were reported as a new class of hybrid porous materials that combine
advantages of both organic polymers and crystalline MOFs. Herein,
we report a bridging coligand strategy to prepare new types of polyMOFs,
demonstrating that polyMOFs are compatible with additional MOF architectures
besides that of the earlier reported IRMOF-1 type polyMOF. Gas sorption
studies revealed that these polyMOF materials exhibited relatively
high CO<sub>2</sub> sorption but very low N<sub>2</sub> sorption,
making them promising materials for CO<sub>2</sub>/N<sub>2</sub> separations.
Moreover, these polyMOFs demonstrated exceptional water stability
attributed to the hydrophobicity of polymer ligands as well as the
cross-linking of the polymer chains within the MOF
Polymer–Metal–Organic Frameworks (polyMOFs) as Water Tolerant Materials for Selective Carbon Dioxide Separations
Recently,
polymer–metal–organic frameworks (polyMOFs)
were reported as a new class of hybrid porous materials that combine
advantages of both organic polymers and crystalline MOFs. Herein,
we report a bridging coligand strategy to prepare new types of polyMOFs,
demonstrating that polyMOFs are compatible with additional MOF architectures
besides that of the earlier reported IRMOF-1 type polyMOF. Gas sorption
studies revealed that these polyMOF materials exhibited relatively
high CO<sub>2</sub> sorption but very low N<sub>2</sub> sorption,
making them promising materials for CO<sub>2</sub>/N<sub>2</sub> separations.
Moreover, these polyMOFs demonstrated exceptional water stability
attributed to the hydrophobicity of polymer ligands as well as the
cross-linking of the polymer chains within the MOF