Mesoporous Framework Research Articles

Creating Tunable Mesoporosity by Temperature-Driven Localized Crystallite Agglomeration.

A new synthetic approach for tunable mesoporous metal-organic frameworks (MeMs) is developed. In this approach, mesopores are created in the process of heat conversion of highly mosaic metal-organic framework (MOF) crystals with non-interpenetrated low-density nanocrystallites into MOF crystals with two-fold interpenetrated high-density nanocrystallites. The two-fold interpenetration reduces the volume of the nanocrystallites in the mosaic crystal, and the accompanying localized agglomeration of the nanocrystallites results in the formation of mesopores among the localized crystallite agglomerates. The pore size can be easily modulated from 7 to 90nm by controlling the heat treatment conditions, that is, the aging temperature and aging time. Various proteins can be encapsulated in the MeM, and immobilized enzymes show catalyst activity comparable to that of the free native enzymes. Immobilized β-galactosidase is recyclable and the enzyme activity of the immobilized catalase is maintained after exposure to high temperatures and various organic solvents.

Surface-Seal Encapsulation of a Homogeneous Catalyst in a Mesoporous Metal-Organic Framework.

A rapid surface sealing strategy has been developed for the encapsulation of a homogeneous catalyst, phosphotungstic acid (PTA), in a mesoporous metal-organic framework (MOF), MIL-101(Cr). This new surface polymerization method utilizes non-solvent-induced phase separation to concentrate and direct polyamine and dianhydride monomers onto MOF particle surfaces, thus realizing the formation of a sub-10 nm, uniform, and cross-linked polymer coating within a few seconds. While fully preserving the catalytic activity of the neat PTA for the catalytic decomposition of phenol, the surface-sealed PTA-MOF composite catalyst can be reused up to 10 times with no noticeable loss of activity and negligible leaching of PTA. Since this surface coating method is not limited by either the MOF or the catalyst, it will become the technique of choice for the immobilization of homogeneous catalysts in MOFs.

Self-template synthesis of mesoporous Au-SnO2 nanospheres for low-temperature detection of triethylamine vapor

The development of metal oxide semiconductor gas sensor for low-temperature detection of hazardous gases (e.g., triethylamine, TEA) is highly desirable, but still challenging. Herein, a self-template synthesis strategy for mesoporous Au-SnO2 nanospheres was developed using nontoxic, renewable and low-cost plant polyphenol as a main chelating agent, tin ions and chloroauric acid as a metal source. Because of the strong chelate ability of polyphenol, a stable Au/tin-polyphenol-formaldehyde sphere is obtained and used as a precursor. After direct calcination process, Au-SnO2 materials with mesoporous crystalline framework, uniform diameter (~120 nm) and high specific surface area (105.2 m2/g) are successfully prepared. The mesoporous Au-SnO2 nanospheres are further used for TEA sensing. They show high response (5.16) at a low temperature (50 ℃) toward TEA. The detection limit was 0.11 ppm. The decoration of Au species can effectively decrease the activation energy and lower the working temperature. After integration with Bluetooth, the gas sensor can be used for wireless monitoring TEA with a low concentration (10–50 ppm) and fast response (~ 30 s). This proposed strategy can be used for mesoporous noble metal-metal oxides and further boost the sensing performance of gas sensor.

In Situ Embedding Synthesis of CsPbBr3@Ce-MOF@SiO2 Nanocomposites for High Efficiency Light-Emitting Diodes: Suppressing Reabsorption Losses through the Waveguiding Effect.

All-inorganic perovskite quantum dots (PQDs), which possess outstanding photophysical properties, are regarded as promising materials for optoelectronic applications. However, the poor light conversion efficiency and severe stability problem hinder their widespread applications. In this work, a novel encapsulation strategy is developed through the in situ growth of CsPbX3 PQDs in presynthesized mesoporous cerium-based metal organic frameworks (Ce-MOFs) and further silane hydrolysis-encapsulation, generating stable CsPbX3@Ce-MOF@SiO2 composites with greatly enhanced light conversion efficiency. Moreover, the simulation results suggest that the pore boundary of Ce-MOFs has a strong waveguide effect on the incident PQD light, constraining PQD light inside the bodies of Ce-MOFs and suppressing reabsorption losses, thus increasing the overall light conversion efficiency of PQDs. Meanwhile, the Ce-MOF@SiO2 protective shell effectively improves the stability by blocking internally embedded PQDs from the harmful external environment. Further, the obtained white-light-emitting diode shows an ultrahigh luminous efficiency of 87.8 lm/W, which demonstrates their great potential in optoelectronic applications.

A mesoporous metal-organic framework used to sustainably release copper(ii) into reducing aqueous media to promote the CuAAC click reaction.

The mesoporous metal-organic framework Cr-MIL-101-NH2 (MOF1) has been used to encapsulate, by a simple impregnation method, large amounts of copper sulfate. The resulting loaded material, Cu@MOF1, was successfully employed to slowly release copper(ii) into an appropriate reaction medium in which the reducing agent sodium ascorbate reduces copper(ii) to copper(i), thus allowing the well-known copper(i)-catalyzed alkyne-azide cycloaddition (CuAAC) "click" reaction to proceed in the absence of potentially high local copper(i) concentrations. The use of a MOF-based controlled copper release system such as Cu@MOF1 may be relevant for copper(i)-catalyzed reactions having substrates that could be degraded by potentially high local concentrations of copper(i). The copper chelating ligand TBTA (tris(benzyltriazolylmethyl)amine), a very useful ligand for click chemistry, has been successfully attached to the pores of MOF1. The resulting TBTA-functionalized MOF (MOF3) was compared with its non-functionalized version (MOF1). At copper loadings of ca. 3 mmol g-1, the results revealed that the performances of the two materials are strikingly similar. Upon immersion in methanol/water (95/5) containing sodium ascorbate, both materials slowly released copper encapsulated in their pores and could be recovered and reused efficiently for up to five reaction cycles without reloading with metal ion, while allowing the CuAAC reaction to proceed with excellent conversion rates and yields.

Engineering monodispersed 2 nm Sb2S3 particles embedded in a porphyrin-based MOF-derived mesoporous carbon network via an adsorption method to construct a high-performance sodium-ion battery anode.

Sodium ion batteries (SIBs) are expected to replace lithium ion batteries (LIBs) as the next generation of large-scale energy storage applications because of their superior cost performance. However, the larger ionic radius of Na+ causes a remarkable volume expansion than that of Li+ during charge and discharge, which reduces the performance of the battery. In this work, we engineered a composite material in that monodispersed 2 nm Sb2S3 particles are uniformly loaded into a carbon matrix (Sb2S3/CZM), which is obtained by carbonization of a zirconium-based MOF with adsorption of Sb. The obtained composite material has a high specific surface area in favor of mass transfer, and the porous structure can resist many volume changes in the circulation process. Moreover, the ultrafine Sb2S3 particles are well-distributed in the composite material, which increases the utilization of the active substance and is promising for the storage of Na+. Based on its unique structure, the Sb2S3/CZM composite shows a specific capacity of 550 mA h g-1 at 100 mA g-1 and an excellent cycling stability of 88.9% retention after 1000 cycles at 3 A g-1. The excellent electrochemical performance provides enlightenment for the rational design of hierarchical heterostructures for energy storage applications.

In Situ Passivation and Thiol-Mediated Anchoring of Perovskite Quantum Dots in Mesoporous Covalent-Organic Frameworks

In Situ Passivation and Thiol-Mediated Anchoring of Perovskite Quantum Dots in Mesoporous Covalent-Organic Frameworks

Rapid Synthesis of Mesoporous Cerium-Based Metal Organic Frameworks for Carbon Dioxide Adsorption and Selectivity

Rapid Synthesis of Mesoporous Cerium-Based Metal Organic Frameworks for Carbon Dioxide Adsorption and Selectivity

Three-dimensional microporous and mesoporous covalent organic frameworks based on cubic building units

Covalent organic frameworks (COFs) have attracted extensive interest due to their unique structures and various applications. However, structural diversities are still limited, which greatly restricts the development of COF materials. Herein, we report two unusual cubic (8-connected) building units and their derived 3D imine-linked COFs with bcu nets, JUC-588 and JUC-589. Owing to these unique building blocks with different sizes, the obtained COFs can be tuned to be microporous or mesoporous structures with high surface areas (2728 m2 g−1 for JUC-588 and 2482 m2 g−1 for JUC-589) and promising thermal and chemical stabilities. Furthermore, the high selectivity of CO2/N2 and CO2/CH4, excellent H2 uptakes, and efficient dye adsorption are observed. This research thus provides a general strategy for constructing stable 3D COF architectures with adjustable pores via improving the valency of rigid building blocks.

Hierarchical mesoporous MoS2 frameworks with conformal carbon coating as a high-rate and stable anode in Li-ion battery

• Hierarchical mesoporous MoS 2 frameworks (HM-MoS 2 ) are synthesized via a facile phase-segregation route. • In situ formed ZnS nanoparticles play a role of the hard template, creating mesopores and interconnected channels. • The mesoporous structure of HM-MoS 2 enables the uniform, protective, and conductive carbon coating (HM-MoS 2 /C 100 ). • HM-MoS 2 /C 100 exhibits a high rate capability of 396.8 mA h g −1 at 10 A g −1 and a prolonged cyclability. Hierarchical or mesoporous-structured molybdenum disulfides (MoS 2 ) are one of the promising anode materials for lithium-ion batteries (LIBs) owing to their abundant active sites, fast ion transport, and easy permeation of electrolyte. However, the synthesis of such architectures with precise structural control is challenging, often requiring preliminary fabrication of templates or special equipment. Herein, we report hierarchical and mesoporous MoS 2 frameworks (HM-MoS 2 ) synthesized via a facile phase-segregation route, where ZnS nanoparticles are in situ formed as the hard template. The mesopores and interconnected channels created by removing ZnS nanoparticles enable the uniform carbon coating on HM-MoS 2 . When employed as an anode in LIB, the HM-MoS 2 of an optimal carbon coating exhibits a high rate capability of 396.8 mA.h g −1 at 10 A g −1 and a prolonged cyclability with only 2.8 % of capacity decay.

Ordered Mesoporous Tio2 Framework Confined Cesn Catalyst Exhibiting Excellent High Activity for Selective Catalytic Reduction of No with Nh3 at Low Temperature

Ordered Mesoporous Tio2 Framework Confined Cesn Catalyst Exhibiting Excellent High Activity for Selective Catalytic Reduction of No with Nh3 at Low Temperature

Synthesis of Mesoporous Zeolites and Their Opportunities in Heterogeneous Catalysis

Currently, zeolites are one of the most important classes of heterogeneous catalysts in chemical industries owing to their unique structural characteristics such as molecular-scale size/shape-selectivity, heterogenized single catalytic sites in the framework, and excellent stability in harsh industrial processes. However, the microporous structure of conventional zeolite materials limits their applications to small-molecule reactions. To alleviate this problem, mesoporous zeolitic frameworks were developed. In the last few decades, several methods have been developed for the synthesis of mesoporous zeolites; these zeolites have demonstrated greater lifetime and better performance than their bulk microporous counterparts in many catalytic processes, which can be explained by the rapid diffusion of reactant species into the zeolite framework and facile accessibility to bulky molecules through the mesopores. Mesoporous zeolites provide versatile opportunities not only in conventional chemical industries but also in emerging catalysis fields. This review presents many state-of-the-art mesoporous zeolites, discusses various strategies for their synthesis, and details their contributions to catalytic reactions including catalytic cracking, isomerization, alkylation and acylation, alternative fuel synthesis via methanol-to-hydrocarbon (MTH) and Fischer–Tropsch synthesis (FTS) routes, and different fine-chemical syntheses.

Bimetallic Ordered Large-Pore MesoMOFs for Simultaneous Enrichment and Dephosphorylation of Phosphopeptides.

Despite the fact that bimetallic metal-organic frameworks (MOFs) could afford multiple functionalities by a synergistic effect of individual metallic centers, their intrinsic microporous structure frequently restricts their wide applications with bulky molecules involved. An urgent need is consequently triggered to design bimetallic hierarchical mesoporous MOFs (mesoMOFs). Herein, Zr/Ce mesoMOFs with a uniform pore size of up to 8 nm was successfully synthesized by a copolymer template strategy with the aid of a Hoffmeister ion. The obtained Zr/Ce mesoMOFs feature high porosity, good chemical and thermal stabilities, and tunable element components, and up to 70% Zr could be incorporated into the mesoporous Ce-based framework without deteriorating its crystallinity. Thanks to the synergistic effect of inherent Ce and Zr as well as the large and open pore channels, a broad range of phosphopeptides with different molecule sizes could be effectively checked out, thanks to their simultaneous enrichment and dephosphorylation capabilities. Such an ability to efficiently concentrate phosphopeptides remained intact even in the presence of abundant non-phosphorylated species. The practical detection of phosphopeptides from human serum was also verified, prefiguring the great potentials of bimetallic large-pore mesoMOFs for the proteome applications.

Hydrocarbon adsorption in a series of mesoporous metal-organic frameworks

A series from five mesoporous metal-organic frameworks [Zn 12 ( i -bdc) 6 (G) 6 (dabco) 3 ] ( i -bdc = isophthalate, G = one of the following: ethylenediolate, 1,2-propylenediolale, 1,2-buthylenediolate, 1,2-pentylenediolate, glycerolate), denoted as NIIC-20-G , show appreciable methane gravimetric adsorption uptakes at high pressure (56 atm), up to 210 cm 3 ⋅g −1 at 273 K and 156 cm 3 ⋅g −1 at 295 K. The corresponding volumetric uptakes reach 175 cm 3 ⋅cm −3 at 273 K and 130 cm 3 ⋅cm −3 at 295 K, approaching to the best reference data for other MOFs. The highest deliverable methane capacity at 295 K was calculated to be 73 cm 3 ⋅cm −3 (pressure range 35–5 atm) and 109 cm 3 ⋅cm −3 (pressure range 65–5 atm). The NIIC-20-G compounds also demonstrate great adsorption capacity towards various volatile organic compounds (benzene, cyclohexane, xylene isomers), irrespective on the chemical nature or geometry of the substrate. The highest vapor adsorption data at 298 K are 6.9 mmol⋅g −1 for the benzene, 5.4 mmol⋅g −1 for the cyclohexane, 4.4 mmol⋅g −1 for o -xylene, 4.5 mmol⋅g −1 for m -xylene and 4.6 mmol⋅g −1 for p -xylene. The compounds NIIC-20-G were shown to maintain their crystal structures as well as their vapor adsorption properties during multiple repeating experiments. Remarkably, the full regeneration of the porous materials could be carried out upon only a mild heating (60 °C). Great adsorption of various volatile hydrocarbons at low concentrations during several cycles and rather mild energy requirements for the material regeneration suggests promising perspectives of NIIC-20-G compounds in air purification applications. • Mesoporous MOFs effectively adsorb CH 4 and various volatile organic compounds. • Great methane adsorption uptakes and high deliverable methane capacities. • Broad-scope adsorption of hydrocarbons, irrespective of their nature and geometry. • Facile regeneration of material with no impact on reproducibility of properties.

Characterization of the size and porous temperature sensitivity of Pluronic F127‒Coated MIL‒88B(Fe) for drug release

Metal-organic frameworks (MOFs) have had varied applications in the biomedical field for decades, with considerable attention on intelligence-triggered drug delivery. In this study, MIL‒88B(Fe) nanomaterials, with gas capture and good biocompatibility, were developed in a fusiform shape. For optimal drug delivery release tests, three Fe sources of MIL‒88B(Fe) were considered for comparing the crystallinity, particle size, morphology, and surface area or pore size distribution. Here, a Pluronic F127 with positive temperature sensitivity was applied during MIL‒88B(Fe) synthesis in a polytetrafluoroethylene-lined autoclave. The pyrolyzed polymer monomers, doped into the lattice during the MIL reassembly, supported the crystallinity and increased the surface area by four times. DLS was used to demonstrate the effectiveness of the changes in particle size distribution. The size distribution of F127‒MIL‒88B(Fe) was sensitive to the increase in temperature, and the size of particles decreased with increasing temperature. As the temperature increased from 25 to 37 °C, the drug release rate of F127‒MIL‒88B(Fe) doubled. The MOFs split into smaller crystals with increase in temperature, which released the drug loaded in the mesoporous frameworks. Thus, polymer-supported F127‒MIL‒88B(Fe) was synthesized with a higher drug capacity based on surface enhancement. Furthermore, a smart temperature-sensitive drug-releasing system was proposed, and it was designed with a releasing allometric kinetics model with release times of t = 0–14.5 h.

Metal organic framework derived SnS@C composites for efficient sodium storage

Tin monosulfide (SnS) has received extensive attention as a promising anode material toward sodium storage for its high specific capacity. Herein, we reported a simple and facile vulcanization reaction to synthesize SnS particles dispersed into carbonaceous mesoporous frameworks using Sn-based MOFs as the precursor template. The unique structure of SnS@C improves electrical conductivity of SnS and promotes the electrons transfer. The as-prepared SnS@C-500 composite displays superior sodium storage performance, which exhibits a high specific capacity of 510 mAh g−1 over 200 cycles at the current density of 0.5 ​A ​g−1, as well as superior rate capabilities. The current MOF-derived synthesis method offers a simple and effective apporach to synthesis in situ SnS/carbonaceous composites electrode materials.

Metal organic frameworks as platforms for the nanostructuring of Mn3 single molecule magnets

In this paper, we report incorporation of the nanostructuration Single-Molecule Magnets (SMMs) Mn3 into mesoporous aluminum-based metal-organic framework (MOF) [Al(OH)(SDC)]n (H2SDC ​= ​4,4′-stilbenedicarboxylic acid), known as CYCU-3. The successful incorporation was confirmed by PXRD, N2 adsorption measurements and thermogravimetric analysis. EDX analysis indicated average 15 ​mol% insertion of SMMs, which is substantial higher than what was previously reported for SMM@silica composites. TGA measurements suggest that MOF can increase the SMM's thermal stability. Magnetic measurements reveal the preservation of the magnetic properties of SMMs inside MOF pores. The AC susceptibility data suggest an effective energy barrier of about 40 ​K for SMM@MOFs composites, slightly lower than those of pristine Mn3 SMMs, which is about 55 ​K.

Selective Mild Oxidation of Anilines into Nitroarenes by Catalytic Activation of Mesoporous Frameworks Linked with Gold-Loaded Mn3 O4 Nanoparticles.

This work reports the synthesis and catalytic application of mesoporous Au-loaded Mn3 O4 nanoparticle assemblies (MNAs) with different Au contents, i. e., 0.2, 0.5 and 1 wt %, towards the selective oxidation of anilines into the corresponding nitroarenes. Among common oxidants, as well as several supported gold nanoparticle platforms, Au/Mn3 O4 MNAs containing 0.5 wt % Au with an average particle size of 3-4 nm show the best catalytic performance in the presence of tert-butyl hydroperoxide (TBHP) as a mild oxidant. In all cases, the corresponding nitroarenes were isolated in high to excellent yields (85-97 %) and selectivity (>98 %) from acetonitrile or greener solvents, such as ethyl acetate, after simple flash chromatography purification. The 0.5 % Au/Mn3 O4 catalyst can be isolated and reused four times without a significant loss of its activity and can be applied successfully to a lab-scale reaction of p-toluidine (1 mmol) leading to the p-nitrotulene in 83 % yield. The presence of AuNPs on the Mn3 O4 surface enhances the catalytic activity for the formation of the desired nitroarene. A reasonable mechanism was proposed including the plausible formation of two intermediates, the corresponding N-aryl hydroxylamine and the nitrosoarene.

Mesoporous carbon framework supported Cu-Fe oxides as efficient peroxymonosulfate catalyst for sustained water remediation

Large-scale green synthesis of high-performance catalysts is desirable for practical application of peroxymonosulfate (PMS) based advanced oxidation process. In this study, mesoporous carbon framework supported Cu-Fe oxides (CuO/CuFe2O4) was synthesized via calcination of cost-effective metal-plant phenolic networks for PMS activation to degrade organic pollutants. The mesoporous carbon framework enables highly spatial dispersion of nanosized Cu-Fe oxides, enhanced adsorption of organic pollutant (Bisphenol A, BPA) and improved electron transfer efficiency. Benefiting from the advantageous structure, the mesoporous carbon framework supported Cu-Fe oxides manifested excellent catalytic efficiency in PMS activation, enabling fast and sustained removal of BPA in simulated and actual contaminated water at neutral pH. Chemical scavenging experiments and electron paramagnetic resonance (EPR) tests revealed that reactive oxygen species (ROS) including SO4•−, OH• and 1O2 all participated in the degradation of BPA. The kinetic study and in situ characterization with ATR-FTIR indicated that PMS was activated by surface Cu(II) through an outer-sphere interaction, and a redox cycle of Cu(II)-Cu(I)-Cu(II) was responsible for the generation of ROS. This work demonstrates a reliable method for rational design of hybrid catalyst of metal oxide and carbon material for efficient wastewater remediation.

Polyvinylpyrrolidone regulated synthesis of mesoporous titanium niobium oxide as high-performance anode for lithium-ion batteries

TiNb2O7 (TNO) as a promising candidate anode for lithium-ion batteries (LIBs) shows obvious advantages in terms of specific capacity and safety, but which undergoes the intrinsic poor electrical and ionic conductivity. Herein, we propose a simple synthesis strategy of mesoporous TNO via a polymeric surfactant-mediated evaporation-induced sol-gel method, using polyvinylpyrrolidone (PVP) with different molecular weights (average Mw: 10000/58000/1300000) as the regulating agent, which greatly affects the lithium storage performance of the as-prepared TNO. The optimized TNO (i.e., PVP of 58000) delivers a high reversible capacity of 303.1 mAh/g at 1 C, with a retention rate of 73.4% (222.5 mAh/g) after 300 cycles. Even at 5 C, a high reversible capacity of 185.6 mAh/g can be achieved, with a retention rate of 72.3% after 1000 cycles. The superior lithium storage behavior is attributed to the fine mesoporous framework consisting of interconnected TNO nanocrystallites with high specific surface area and high mesoporosity, which greatly increases the active sites, improves the Li+ diffusion kinetics and alleviates volume fluctuation induced by the repetitive Li+ insertion-extraction processes.