Metal-organic frameworks based on pyrazolates for the selective and efficient capture of formaldehyde.

Indoor air pollution is one of the major threads in developed countries, notably due to high concentrations of formaldehyde, a harmful molecule difficult to eliminate. Addressing this purification challenge while adhering to the principles of sustainable development requires the use of innovative, advanced sustainable materials. Here we show that by combining state-of-the-art spectroscopic techniques with density-functional theory molecular simulations, we have developed an advantageous mild chemisorption synergistic mechanism using porous metal (III or IV) pyrazole- di-carboxylate based metal-organic framework (MOF) to trap formaldehyde in a reversible manner, without incurring significant energy penalties for regeneration.

A Scalable Robust Microporous Al-MOF for Post-Combustion Carbon Capture.

Herein, a robust microporous aluminum tetracarboxylate framework, MIL-120(Al)-AP, (MIL, AP: Institute Lavoisier and Ambient Pressure synthesis, respectively) is reported, which exhibits high CO uptake (1.9 mmol g at 0.1 bar, 298 K).

A Versatile Shaping Method of Very-High Loading Porous Solids Paper Adsorbent Composites.

Owing to their high porosity and tunability, porous solids such as metal-organic frameworks (MOFs), zeolites, or activated carbons (ACs) are of great interest in the fields of air purification, gas separation, and catalysis, among others. Nonetheless, these materials are usually synthetized as powders and need to be shaped in a more practical way that does not modify their intrinsic property (i.e.

Adsorption and dynamics of linear and mono-branched hexane isomers in MIL-140 metal-organic frameworks.

Recent breakthrough experiments revealed the iso-reticular Zr-MOFs, MIL-140B and MIL-140C, as promising sorbents for the separation of C6 isomers. Interestingly while the ultra-small pore MIL-140B exhibited hexane isomer sorption hierarchy according to the normal boiling point order (-C6 > 3MP (3-methyl pentane)), an uncommon shift in the elution order was observed in the larger pore MIL-140C. It was only speculated that the flexibility of the MOFs might be the origin of this intriguing behavior.

Hierarchical superparamagnetic metal-organic framework nanovectors as anti-inflammatory nanomedicines.

Among a plethora of drug nanocarriers, biocompatible nanoscale metal-organic frameworks (nanoMOFs) with a large surface area and an amphiphilic internal microenvironment have emerged as promising drug delivery platforms, mainly for cancer therapy. However, their application in biomedicine still suffers from shortcomings such as a limited chemical and/or colloidal stability and/or toxicity. Here, we report the design of a hierarchically porous nano-object (denoted as USPIO@MIL) combining a benchmark nanoMOF (that is, MIL-100(Fe)) and ultra-small superparamagnetic iron oxide (USPIO) nanoparticles (that is, maghemite) that is synthesized through a one-pot, cost-effective and environmentally friendly protocol.

When Polymorphism in Metal-Organic Frameworks Enables Water Sorption Profile Tunability for Enhancing Heat Allocation and Water Harvesting Performance.

The development of thermally driven water-sorption-based technologies relies on high-performing water vapor adsorbents. Here, polymorphism in Al-metal-organic frameworks is disclosed as a new strategy to tune the hydrophilicity of MOFs. This involves the formation of MOFs built from chains of either trans- or cis- µ-OH-connected corner-sharing AlO(OH) octahedra.

MOFs with Open Metal(III) Sites for the Environmental Capture of Polar Volatile Organic Compounds.

Metal-Organic Frameworks (MOFs) with open metal sites (OMS) interact strongly with a range of polar gases/vapors. However, under ambient conditions, their selective adsorption is generally impaired due to a high OMS affinity to water. This led previously to the privilege selection of hydrophobic MOFs for the selective capture/detection of volatile organic compounds (VOCs).

Separation of Branched Alkanes Feeds by a Synergistic Action of Zeolite and Metal-Organic Framework.

Zeolites and metal-organic frameworks (MOFs) are considered as "competitors" for new separation processes. The production of high-quality gasoline is currently achieved through the total isomerization process that separates pentane and hexane isomers while not reaching the ultimate goal of a research octane number (RON) higher than 92. This work demonstrates how a synergistic action of the zeolite 5A and the MIL-160(Al) MOF leads to a novel adsorptive process for octane upgrading of gasoline through an efficient separation of isomers.

MOFs industrialization: a complete assessment of production costs.

The potential of safe and low-cost batch production processes for Metal-Organic Frameworks (MOFs) at an industrial scale has been evaluated based on the prototypical MOF MIL-160(Al), a bio-derived material of high practical interest that can be made with a high space-time yield using green ambient pressure conditions. A simple method to calculate the production cost of this material has been determined based on a simulated process constructed with the data collected from laboratory pilot large-scale tests taking into account for the first time in MOF cost evaluation all the process parameters such as the scale, the cost of the raw materials, recirculation, and washing. The investment for a production plant established the ground for the estimation of the complete cost.

One-Step Room-Temperature Synthesis of Metal(IV) Carboxylate Metal-Organic Frameworks.

Room-temperature syntheses of metal-organic frameworks (MOFs) are of interest to meet the demand of the sustainable chemistry and are a pre-requisite for the incorporation of functional compounds in water-stable MOFs. However, only few routes under ambient conditions have been reported to produce metal(IV)-based MOFs. Reported here is a new versatile one-step synthesis of a series of highly porous M -oxocluster-based MOFs (M=Zr, Hf, Ce) at room temperature, including 8- or 12-connected micro/mesoporous solids with different functionalized organic ligands.

Enhancement of Ethane Selectivity in Ethane-Ethylene Mixtures by Perfluoro Groups in Zr-Based Metal-Organic Frameworks.

A series of zirconium dicarboxylate-based metal-organic frameworks (Zr MOFs) of the UiO-66 (tetrahedral and octahedral cages) or MIL-140 (triangular channels) structure type were investigated for the separation of ethane/ethylene mixtures. The adsorption, investigated both experimentally and computationally, revealed that the size and type of pores have a more pronounced effect on the selectivity than the aromaticity of the linker. The increase in pore size when changing from benzene to naphthalene (NDC) dicarboxylate ligand makes UiO-NDC less selective (1.

Metal-Organic Frameworks as advanced moisture sorbents for energy-efficient high temperature cooling.

Latent cooling load accounts for 30% of the total load of air-conditioning, and its proportion is even higher in many tropical and subtropical climates. Traditional vapour-compression air-conditioning (VCAC) has a low coefficient of performance (COP) due to the refrigeration dehumidification process, which often makes necessary a great deal of subsequent re-heating. Technologies using conventional desiccants or sorbents for indoor moisture control are even less competitive than VCAC due to their high regeneration temperature, long cycling time and bulky components.

A phase transformable ultrastable titanium-carboxylate framework for photoconduction.

Porous titanium oxide materials are attractive for energy-related applications. However, many suffer from poor stability and crystallinity. Here we present a robust nanoporous metal-organic framework (MOF), comprising a TiO oxocluster and a tetracarboxylate ligand, achieved through a scalable synthesis.

Metal-Organic Frameworks for Cultural Heritage Preservation: The Case of Acetic Acid Removal.

The removal of low concentrations of acetic acid from indoor air at museums poses serious preservation problems that the current adsorbents cannot easily address owing to their poor affinity for acetic acid and/or their low adsorption selectivity versus water. In this context, a series of topical water-stable metal-organic frameworks (MOFs) with different pore sizes, topologies, hydrophobic characters, and functional groups was explored through a joint experimental-computational exploration. We demonstrate how a subtle combination of sufficient hydrophobicity and optimized host-guest interactions allows one to overcome the challenge of capturing traces of this very polar volatile organic compound in the presence of humidity.

Cooperative Adsorption by Porous Frameworks: Diffraction Experiment and Phenomenological Theory.

Materials science of metal open frameworks is a state-of-the-art field for numerous applications, such as gas storage, sensors, and medicine. Two nanoporous frameworks, γ-Mg(BH ) and MIL-91(Ti), with different levels of structural flexibility, were examined with in situ X-ray diffraction guest adsorption-desorption experiments. Both frameworks exhibit a cooperative guest adsorption correlated with a lattice deformation.

Diffusion of Carbon Dioxide and Nitrogen in the Small-Pore Titanium Bis(phosphonate) Metal-Organic Framework MIL-91 (Ti): A Combination of Quasielastic Neutron Scattering Measurements and Molecular Dynamics Simulations.

The diffusivity of CO and N in the small-pore titanium-based bis(phosphonate) metal-organic framework MIL-91(Ti) was explored by using a combination of quasielastic neutron scattering measurements and molecular dynamics simulations. These two techniques were used to determine the loading dependence of the self-diffusivity, corrected and transport diffusivities of these two gases to complement our previously reported thermodynamics study, which revealed that this material was a promising candidate for CO /N separation. The calculated and measured diffusivities of both gases were shown to be of an order of magnitude sufficiently high, from 10 to 10  m  s , and N diffused faster than CO through the small channel of MIL-91(Ti).

Synthesis Optimization, Shaping, and Heat Reallocation Evaluation of the Hydrophilic Metal-Organic Framework MIL-160(Al).

The energy-storage capacities of a series of water-stable porous metal-organic frameworks, based on high-valence metal cations (Al , Fe , Cr , Ti , Zr ) and polycarboxylate linkers, were evaluated under the typical conditions of seasonal energy-storage devices. The results showed that the microporous hydrophilic Al-dicarboxylate MIL-160(Al) exhibited one of the best performances. To assess the properties of this material for space-heating applications on a laboratory pilot scale with an open reactor, a new synthetic route involving safer, greener conditions was developed.

Proton Transport in a Highly Conductive Porous Zirconium-Based Metal-Organic Framework: Molecular Insight.

The water stable UiO-66(Zr)-(CO2H)2 MOF exhibits a superprotonic conductivity of 2.3×10(-3)  S cm(-1) at 90 °C and 95 % relative humidity. Quasi-elastic neutron scattering measurements combined with aMS-EVB3 molecular dynamics simulations were able to probe individually the dynamics of both confined protons and water molecules and to further reveal that the proton transport is assisted by the formation of a hydrogen-bonded water network that spans from the tetrahedral to the octahedral cages of this MOF.

Tuning the properties of the UiO-66 metal organic framework by Ce substitution.

Crystallisation of a mixed-metal form of the porous framework UiO-66 in which Zr is partially replaced by Ce produces a ligand-defective material, that contains some Ce(III) as well as a majority of Ce(IV). Infrared spectroscopy shows enhanced binding of methanol in the substituted material that leads to catalytic decomposition of the alcohol, which may be due to a combination of defects and redox activity.

The structure of the aluminum fumarate metal-organic framework A520.

The synthesis of the commercially available aluminum fumarate sample A520 has been optimized and its structure analyzed through a combination of powder diffraction, solid-state NMR spectroscopy, molecular simulation, IR spectroscopy, and thermal analysis. A520 is an analogue of the MIL-53(Al)-BDC solid, but with a more rigid behavior. The differences between the commercial and the optimized samples in terms of defects have been investigated by in situ IR spectroscopy and correlated to their catalytic activity for ethanol dehydration.

Tuning the breathing behaviour of MIL-53 by cation mixing.

A mixed cation MIL-53(Cr-Fe) MOF has been obtained by direct synthesis. Multiple experimental techniques have demonstrated the presence of a genuine mixed phase, leading to a breathing behaviour different from either of the single cation analogues.

Cathode composites for Li-S batteries via the use of oxygenated porous architectures.

Li-S rechargeable batteries are attractive for electric transportation because of their low cost, environmentally friendliness, and superior energy density. However, the Li-S system has yet to conquer the marketplace, owing to its drawbacks, namely, soluble polysulfide formation. To tackle this issue, we present here a strategy based on the use of a mesoporous chromium trimesate metal-organic framework (MOF) named MIL-100(Cr) as host material for sulfur impregnation.

Exceptional stability and high hydrogen uptake in hydrogen-bonded metal-organic cubes possessing ACO and AST zeolite-like topologies.

Herein we detail a novel approach for targeting zeolite-like metal-organic frameworks (ZMOFs) that utilizes metal-organic cubes, which are regarded as double four-membered rings (d4Rs) and are composite building units (BUs) in traditional inorganic zeolites. Accordingly, we outline the successful implementation of this strategy by reporting two ZMOFs with ACO and AST zeolite-like topologies, which were constructed from d4R BUs exclusively held together by hydrogen bonds. Their porosity was evaluated, delineating high hydrogen uptake and exceptional stability for the two hydrogen-bonded materials.

Zeolite-like metal-organic frameworks (ZMOFs) as hydrogen storage platform: lithium and magnesium ion-exchange and H(2)-(rho-ZMOF) interaction studies.

Zeolite-like metal-organic frameworks (ZMOFs) are anionic, have readily exchangeable extra-framework cations, and can be constructed with a variety of organic linkers. ZMOFs therefore can be regarded as an excellent platform for systematic studies of the effect(s) of various structural factors on H(2) binding/interaction with porous metal-organic materials. We find that the enhanced binding of molecular hydrogen in ion-exchanged ZMOFs with an anionic framework is largely governed by the presence of the electrostatic field in the cavity, which is reflected by isosteric heats of adsorption in these compounds which are greater by as much as 50% relative to those in neutral MOFs.