Nanoporous Framework Research Articles

Nanoporous 3D Covalent Organic Frameworks with pts Topology as Anticancer Drug Nanocarriers

Nanoporous 3D Covalent Organic Frameworks with pts Topology as Anticancer Drug Nanocarriers

Nanoporous N-Rich Covalent Organic Frameworks with High Specific Surface Area for Efficient Adsorption of Iodine and Methyl Iodide

Nanoporous N-Rich Covalent Organic Frameworks with High Specific Surface Area for Efficient Adsorption of Iodine and Methyl Iodide

A novel technique for porous framework cordierite synthesis at room temperature and its catalytic cracking of waste polypropylene to produce motor oil and petrol

Conventional Cordierite is a non-framework metal oxide composite and is synthesized above 1000 °C. In our present investigation, Tetraethylenepentamine (TEPA) is a template for the synthesis of nanoporous tetrahedral framework cordierite (Aluminosilicate) at room temperature. Co2+ (non-isomorphous substitution) and Mn2+ (isomorphous substitution) are performed to produce α- cordierite and β-cordierite respectively. Both metal ions are in octahedral coordination by the direction of the template. Synthesized materials are characterized by FT-IR, XRD, BET and TEM are confirmed the framework, crystallinity, porosity and morphology respectively. BET analysis is shown that pore shapes for α- cordierite (13.5 nm) are H1 type and β-cordierite (11.9 nm) is H3 type hysteresis loop. Both cordierites are applied for the waste polypropylene cracking reaction. It is observed that α- cordierite has produced motor oil as a major product and β – cordierite has produced petrol as a major product.

Nanoporous Triangulene-Based Frameworks for the Separation of Petroleum Hydrocarbons: Electronic, Magnetic, Optical, and Adsorption Properties

Nanoporous Triangulene-Based Frameworks for the Separation of Petroleum Hydrocarbons: Electronic, Magnetic, Optical, and Adsorption Properties

Robust Fluorine-Functionalized {Ln5}-Organic Frameworks for Excellent Catalytic Performance on Cycloaddition of CO2 with Epoxides and Knoevenagel Condensation.

Lanthanide-organic frameworks (LnOFs) are a class of promising catalysts on a large number of organic reactions because of the higher coordination number of Ln3+ ions, inspired by which exploratory preparation of cluster-based LnOFs was carried out by us. Herein, the exquisite combination of spindly [Ln5(μ3-OH)6(CO2)6(H2O)6] clusters (abbreviated as {Ln5}) and fluorine-functionalized tetratopic ligand of 2',3'-difluoro-[p-terphenyl]-3,3″,5,5″-tetracarboxylic acid (F-H4PTTA) engendered two highly robust isomorphic nanoporous frameworks of {[Ln5(FPTTA)2(μ3-OH)6(H2O)6](NO3)}n (NUC-61, Ln = Ho and Dy). NUC-61 compounds are rarely reported {Ln5}-based 3D frameworks with nano-caged voids (19 Å × 17 Å), which are shaped by twelve [Ln5(μ3-OH)6(COO)8] clusters and eight completely deprotonated F-PTTA4- ligands. Activated NUC-61a compounds are characterized by plentiful coexisted Lewis acid-base sites of open LnIII sites, capped μ3-OH, and -F. Judged by the ideal adsorbed solution theory (IAST), activated NUC-61Ho-a had a high CO2/CH4 adsorptive selectivity with the value of 12.7 (CO2/CH4 = 50/50) and 9.1 (CO2/CH4 = 5/95) at 298 K, which could lead to high-purity CH4 (≥99.9996%). Furthermore, catalytic experiments exhibited that NUC-61Ho-a, as a representative, could efficiently catalyze the cycloaddition reactions of CO2 with epoxides as well as the Knoevenagel condensation reactions of aldehydes and malononitrile. This work proves that the {Ln5}-based skeletons of NUC-61 with chemical stability, heterogeneity, and recyclability are an excellent acid-base bifunctional catalyst for some organic reactions.

Microscopic Origin of Electrochemical Capacitance in Metal-Organic Frameworks.

Electroconductive metal-organic frameworks (MOFs) have emerged as high-performance electrode materials for supercapacitors, but the fundamental understanding of the underlying chemical processes is limited. Here, the electrochemical interface of Cu3(HHTP)2 (HHTP = 2,3,6,7,10,11-hexahydroxytriphenylene) with an organic electrolyte is investigated using a multiscale quantum-mechanics/molecular-mechanics (QM/MM) procedure and experimental electrochemical measurements. Our simulations reproduce the observed capacitance values and reveals the polarization phenomena of the nanoporous framework. We find that excess charges mainly form on the organic ligand, and cation-dominated charging mechanisms give rise to greater capacitance. The spatially confined electric double-layer structure is further manipulated by changing the ligand from HHTP to HITP (HITP = 2,3,6,7,10,11-hexaiminotriphenylene). This minimal change to the electrode framework not only increases the capacitance but also increases the self-diffusion coefficients of in-pore electrolytes. The performance of MOF-based supercapacitors can be systematically controlled by modifying the ligating group.

Design of hydroxyl-functionalized nanoporous organic polymer with tunable hydrophilic-hydrophobic surface for solid phase extraction of neonicotinoid insecticides.

As being widely used insecticides, neonicotinoid residues are toxic and harmful to human health and aquatic ecosystems. Thus, the sensitive monitoring of neonicotinoids in water and food samples is highly desirable to reduce their risks to humans. Herein, four novel hydroxyl-functionalized nanoporous organic frameworks (OH-NOP1, OH-NOP2, OH-NOP3 and OH-NOP4) with tunable hydrophilic-hydrophobic surface have been designed and fabricated for the first time by employing luteolin as monomer and 4,4'-bis(chloromethyl)-1,1'-biphenyl as crosslinker at the molar ratio of 3:1, 1:1, 1:3 and 1:6, respectively. When the molar ratio of luteolin to crosslinker was 1:3, OH-NOP3 was obtained and it presented the highest affinity with excellent adsorption performance towards the studied neonicotinoids. The adsorption mechanism was proposed to be the strong hydrogen bond, polar interaction, Lewis acid-base interaction and pore adsorption between OH-NOP3 and neonicotinoids. Then, utilizing OH-NOP3 as sorbent for solid phase extraction cartridges, an effective method for extraction and preconcentration of neonicotinoids followed by high performance liquid chromatography analysis has been developed for quantitative detection of neonicotinoids from water and edible fungi. The method provided good linearity over the range of 0.06-100.0ngmL-1 for lake water, 1.5-100.0ngg-1 for pleurotus eryngii and sea-shroom. Low detection limit (at the signal to noise ratio of 3) was achieved in the range of 0.02-0.08ngmL-1 for water, 0.50-0.60ngg-1 for pleurotus eryngii and 0.50-0.80ngg-1 for sea-shroom, while the limit of quantification was 0.06-0.25ngmL-1, 1.50-1.80ngg-1 and 1.50-2.50ngg-1, respectively. Satisfactory method recoveries (85.1-112%) were obtained, with relative standard deviations below 8.2%. This study offered a new strategy for designing efficient sorbents to adsorb or remove organic pollutants based on the structure and properties of substrates.

Designing the Macroporous Structure of Three-Way Catalyst Particles: The Influence of Template Concentration on Framework Thickness and Mass Transfer.

Mass transfer is an essential process that can extend the performance and utilization of nanoporous materials in various applications. Therefore, improving mass transfer in nanoporous materials has always attracted much interest, and macroporous structures are currently being studied to enhance mass transfer performance. The introduction of macroporous structures into three-way catalysts (TWC), which are widely utilized to control the emission of polluted gases from vehicles, provides the potential to enhance their mass transfer property and catalytic performance. However, the formation mechanism of macroporous TWC particles has not yet been investigated. On the other hand, the influence of the framework thickness of the macroporous structure on the mass transfer enhancement is still unclear. Therefore, this report investigates the particle formation and framework thickness of the macroporous TWC particles synthesized using the template-assisted aerosol process. The formation of macroporous TWC particles was precisely controlled and investigated by altering the size and concentration of the template particles. The template concentration played a crucial role in maintaining the macroporous structure and controlling the framework thickness between the macropores. Based on these results, a theoretical calculation showing the influence of template concentration on the particle morphology and framework thickness was developed. The final results showed that increasing the template concentration can positively affect the nanoporous material's framework thickness reduction and mass transfer coefficient improvement.

Engineering transport highways in microporous membranes for lithium extraction: The double role of covalent organic frameworks

Microporous polyamide membranes that allow lithium ions to pass through easily but exclude magnesium ions hold vast potential in the lithium extraction from brine lakes. The efficacy, nevertheless, has long been limited by a trade-off that the magnesium/lithium selectivity is received at the expense of the permeability, arising from the highly cross-linked polyamide. This work describes that rationally lowering the internal density of polyamides by embedding functionalized covalent organic framework (COF) nanosheets can boost the selectivity and permeability simultaneously. A cationic COF, TpTGCl, is used to build transport highways in membranes, which shows the double role that not only lowers the polyamide density in a controllable way, but also strengthens the positive charge property. The resulting membrane exhibits a large water permeance of 19.6 L m−2 h−1 bar−1, along with an excellent separation factor of up to 21.3 under a high magnesium/lithium ratio of 30. This engineering strategy offers a means by which charged and nanoporous two-dimensional frameworks can be leveraged as a booster for microporous membranes enabling fast and precise ion transports.

An Artificial Compartmentalized Biocatalytic Cascade System Constructed With Enzyme‐Caged Reticulate Nanoporous Membranes

AbstractCompartmentalization is a ubiquitous feature of life, with a membrane interface that regulates molecular transport and exhibits bioactivities. An artificial enzyme‐integrated membrane cascade system can mimic such interactive properties across different length scales for in vitro application. Here, it is shown that a reticulated nanoporous framework membrane with nano‐caged enzymes presents the first modular macroscale platform for the compartmentalized biocatalytic system interfaced with an external medium. Catalase (CAT)‐integrated polyurea membrane scaffold is prepared by a simple pressurization procedure for a model cyclic cascade of glucose oxidase/catalase (GOx/CAT). The bicontinuous nanoporous membrane readily constructs a compartmentalized system interfacing the glucose/GOx solution and the external environment and mediates glucose oxidation by a cascade reaction under anaerobic or aerobic conditions. Furthermore, the membrane compartment exhibits multiple bioactive capabilities and barrier properties, including hydrogen peroxide detoxification, in situ oxygen generation, and protease exclusion. This work suggests a new strategy toward a robust modular biocatalytic membranous interface to mediate biochemical reaction cascades occurring in a compartment interfaced to an external environment, promising for potential applications in biohybrid devices embedded with tissues and cells.

Nanoporous Vinylene-Linked 2D Covalent Organic Frameworks for Visible-Light-Driven Aerobic Oxidation

Exploring vinylene-linked nanoporous covalent organic framework (COF) materials has become a valuable research focus due to their various outstanding properties. However, only a few examples have been reported to construct vinylene-linked COFs, which seriously restricted their applications. Herein, two COFs linked by olefins TC-PT and TC-PB via the Knoevenagel condensation of 1,3,5-tris(4-cyanomethylphenyl) benzene and 2,4,6-tris (4-formylphenyl)-1,3,5-triazine or 1,3,5-tris (4-formylphenyl) benzene were designed and constructed, which possessed high crystallinity, remarkable porosity, and high structural, chemical, and thermal stability. The two nanoporous organic framework materials prepared can be used for catalytic organic reaction of phenylboric acid and its derivatives driven efficiently by visible light. It is noted that TC-PT with a donor–acceptor structure presented excellent activity, yield, and recyclability. We believed that this work would provide some precious insights for developing functional vinylene-linked COFs.

Triggering the Vapochromic Behavior in C60 via the Supramolecular Wrapping of st-PMMA

Understanding the physicochemical modulation of functional molecules is the primary step in exploring novel stimuli-responsive materials, and preventing the π-π stacking configuration of π-conjugated molecules has been an effective strategy of vapochromic material development, such as of nanoporous frameworks. Nevertheless, the more complicated synthetic strategy should in fact be applied in many circumstances. In this study, we explore a facile supramolecular strategy where the commodity plastic, syndiotactic-poly(methyl methacrylate) (st-PMMA), is utilized to wrap C60 to form the inclusion complex. The structural characterization revealed that C60s in the st-PMMA supramolecular helix had a lower coordination number (CN = 2) compared to the face-centered-cubic packing of pure C60s (CN = 12). Since the st-PMMA/C60 helical complex has structural flexibility, the π-π stacking structure of C60 was further interrupted by the intercalation of toluene vapors, and the complete isolation of C60 in the complex induced the desired vapochromic behavior. Furthermore, the aromatic interaction between C60 and aromatic solvent vapors enabled the st-PMMA/C60 inclusion complex to selectively encapsulate chlorobenzene, toluene, etc., and induce the color change. The st-PMMA/C60 inclusion complex exhibited a transparent film of sufficient structural integrity such that it can still induce a reversible color change after several cycles. As a result, a new strategy has been discovered for the development of novel vapochromic materials via host-guest chemistry.

Eu3+-Functionalized Nanoporous Covalent Organic Frameworks for Fluorescence Detection and Removal of Tetracycline

Tetracycline (TC) abuse has caused a serious threat to human health and the ecological environment, so it is very important to develop the materials that can simultaneously detect and remove TC in animal feed and environmental water. In this present work, at first, an original oxygen-rich 2D nanoporous covalent organic framework (BrPz-COF) was synthesized by an irreversible condensation reaction of tetrabromo-1,4-benzoquinone and piperazine and then a rare-earth covalent organic framework (Ln@COF) was successfully obtained for the detection and removal of tetracycline by post-synthesis modification. The carbonyl group contained in BrPz-COF provides a large number of active sites for the binding of Eu3+ ions by post-synthetic modifications so that the resulting Eu3+@BrPz-COF hybrid shows a good chemical stability under harsh chemical conditions such as strong acid, strong base, and various organic solvents. The resulting Eu3+@BrPz-COF exhibited a turn-on response toward tetracycline, which allowed this interesting material to be applied as a fluorescence sensor. It is worth mentioning that the reusable sensor had a high sensitivity and excellent selectivity to TC, and the detection limit was 7 nM, which can be applied to detect TC in animal feed. In addition, Eu3+@BrPz-COF also showed a good performance in the removal of TC with the maximum adsorption amount of 205.34 mg·g–1. Metal-COF-based hybrid materials with the performances of simultaneous detection and removal of TC are rare, so this work is very significant for developing a material to solve this matter.

Highly Robust {In2}-Organic Framework for Efficiently Catalyzing CO2 Cycloaddition and Knoevenagel Condensation.

To improve the catalytic performance of metal-organic frameworks (MOFs), creating higher defects is now considered as the most effective strategy, which can not only optimize the Lewis acidity of metal ions but also create more pore space to enhance diffusion and mass transfer in the channels. Herein, the exquisite combination of scarcely reported [In2(CO2)5(H2O)2(DMF)2] clusters and 2,6-bis(2,4-dicarboxylphenyl)-4-(4-carboxylphenyl)pyridine (H5BDCP) under solvothermal conditions generated a highly robust nanoporous framework of {[In2(BDCP)(DMF)2(H2O)2](NO3)}n (NUC-65) with nanocaged voids (14.1 Å) and rectangular nanochannels (15.94 Å × 11.77 Å) along the a axis. It is worth mentioning that an In(1) ion displays extremely low tetra-coordination modes after the thermal removal of its associated four solvent molecules of H2O and DMF. Activated {[In2(BDCP)](Br)}n (NUC-65Br), as a defective material because of its extremely unsaturated metal centers, could be generated by bromine ion exchange, solvent exchange, and vacuum drying. Catalytic experiments proved that the conversion of epichlorohydrin with 1 atm CO2 into 4-(chloromethyl)-1,3-dioxolan-2-one catalyzed by 0.11 mol % NUC-65Br could reach 99% at 65 °C within 24 h. Moreover, with the aid of 5 mol % cocatalyst n-Bu4NBr, heterogeneous NUC-65Br owns excellent universal catalytic performance in most epoxides under mild conditions. In addition, NUC-65Br, as a heterogeneous catalyst, exhibits higher activity and better selectivity for Knoevenagel condensation of aldehydes and malononitrile. Hence, this work offers a fresh insight into the design of structure defect cationic metal-organic frameworks, which can be better applied to various fields because of their promoted performance.

Nanoporous Sulfonic Covalent Organic Frameworks for Selective Adsorption and Separation of Lanthanide Elements

Lanthanides are a group of important elements and have been widely used in many fields. Their separation is crucial for technical applications, but it remains a troublesome task due to their subtly different properties. Herein, novel nanoporous sulfonic covalent organic frameworks were synthesized by the Schiff base reaction of 1,3,5-tris(p-formylphenyl)benzene (TFPB) and 2,5-diaminobenzene-1,4-disulfonic acid (DABDA) under mild conditions, which were defined as TFPB-DABDA iCOFs and used for highly selective adsorption separation of lanthanide elements. These iCOFs have uniform morphology, good stability, and excellent adsorption separation ability. The experiment results indicate that the adsorption capacity of TFPB-DABDA iCOFs is highly sensitive to the ionic radius. It means that the larger the size difference between ions, the higher the separation selectivity, especially in the early lanthanides (La3+, Ce3+, Pr3+, Nd3+, Sm3+, Eu3+, and Gd3+) and late lanthanides (Tb3+, Dy3+, Ho3+, Er3+, Tm3+, and Lu3+). The separation mechanism of lanthanide elements by TFPB-DABDA iCOFs may be related to the sulfonic acid groups in the ordered channels of the COFs. This work develops a simple and efficient strategy for the synthesis of iCOFs, which shows a promising application of effective adsorption separation of lanthanides.

Rational Design of Covalent Organic Frameworks as Gas Diffusion Layers for Multi-atmosphere Lithium-Air Batteries.

Non-aqueous Li-air batteries, despite their high energy density and low cost, have not been deployed practically due to their instability in ambient air, where moisture causes parasitic reactions and shortens their life drastically. Here, we demonstrate the rational design of nanoporous covalent organic frameworks (COFs) as effective gas diffusion layers (GDLs) to address this constraint. The COF GDLs, with a tailor-made pore size of ~1.4 nm and superhydrophobicity can limit the intrusion of organic electrolytes and moisture into the gas diffusion channels, enabling high capacity, fast kinetics, and excellent stability of the Li-air batteries. Moreover, we achieve multi-atmosphere Li-air batteries, which can stably cycle under open ambient air (relative humidity up to 95%) and even in various atmospheres with looping oxygen, humid air, and carbon dioxide. The design principles of our COF GDLs can be universally applied in energy storage and electrochemical systems using organic electrolytes.

Rational Design of Covalent Organic Frameworks as Gas Diffusion Layers for Multi‐atmosphere Lithium‐Air Batteries

AbstractNon‐aqueous Li‐air batteries, despite their high energy density and low cost, have not been deployed practically due to their instability in ambient air, where moisture causes parasitic reactions and shortens their life drastically. Here, we demonstrate the rational design of nanoporous covalent organic frameworks (COFs) as effective gas diffusion layers (GDLs) to address this constraint. The COF GDLs, with a tailor‐made pore size of ≈1.4 nm and superhydrophobicity, can limit the intrusion of organic electrolytes and moisture into the gas diffusion channels, enabling high capacity, fast kinetics, and excellent stability of the Li‐air batteries. Moreover, we achieve multi‐atmosphere Li‐air batteries, which can stably cycle under open ambient air (relative humidity up to 95 %) and even in various atmospheres with looping oxygen, humid air, and carbon dioxide. The design principles of our COF GDLs can be universally applied in energy storage and electrochemical systems using organic electrolytes.

Effective Iodine Adsorption by Nitrogen-Rich Nanoporous Covalent Organic Frameworks

With the rapid development of the nuclear industry, the effective treatment of radioactive iodine has currently become an urgent but challenging task. Herein, two covalent organic frameworks (COFs), TFBT-1 and TFBT-2, were successfully synthesized for iodine adsorption. Structure analysis revealed that they are both nanoporous materials with one-dimensional channels derived from the packing of the related two-dimensional frameworks. Iodine adsorption experiments demonstrated that both COF materials exhibit effective performance for iodine adsorption, with a maximum amount of upto 3.15 g g–1 for TFBT-1 and 2.60 g g–1 for TFBT-2. The results of experimental analyses of Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy clearly revealed that their high performance is attributed to the strong interactions between the adsorbed iodine and the uniformly located abundant nitrogen adsorption sites in the pores of the two COF materials, which are from both pre-introduced acylamides and in situ-generated Schiff base imine groups. The present work revealed that by introducing the nitrogen-rich sites into the frameworks of the COF materials, effective iodine adsorbents can be achieved.

Construct a porous carbon structure 3D-NOPC doped with N and O as the sulfur main body for durable lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries have consistently demonstrated high specific energy capacity and density, making them one of the most promising lithium-ion battery successors. However, the shuttle effect of polysulfide intermediates and the low conductivity of S/Li2S, greatly confine the Li-S battery applications. Herein, we utilized a one-step carbonization technique for synthesizing nitrogen (N) and oxygen (O) double-doped three-dimensional porous carbon (3D-NOPC) to overcome these difficulties. One-step carbonization of sodium citrate combined with polyvinyl pyrrolidone (PVP) yields 3D nanoporous carbonaceous frameworks which achieve porosity for sulfur species accommodation and confinement effect simultaneously. The porous carbon structure of the 3D-NOPC host owns a huge surface area (490 m2 g−1) and pore volume (0.385 cm3 g−1) as well as a high N, O doping concentration (2.8 and 5.3 at%). The 3D-NOPC@S cathode delivers a reversible capacity of around 900 mAh g−1 at 0.5 C and a maintained capacity of 703 mAh g−1 after 200 cycles, in virtue of the confinement effect, polysulfides adsorption, and conductivity enhancement. The initial cyclic discharge specific capacity of the 3D-NOPC@S cathode is 617 mAh g−1 at 2 C rate, with a reversible capacity of 543 mAh g−1 after 500 cycles and superb cycling stability with an ultralow decay rate of 0.024% per cycle. This research uses hierarchical porous materials engineering to limit shuttle polysulfide moieties in sulfur host materials for efficient and stable Li-S batteries.

Pre-zeolite framework super-MIEC anodes for high-rate lithium-ion batteries

New physical insights and a robust approach are provided to develop super-MIEC anodes for high-rate batteries, which would bridge two materials families—nanoporous framework materials and conductive oxides.