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Новости Nature

Nitrogen-doped mesoporous SiC materials with catalytically active cobalt nanoparticles for the efficient and selective hydrogenation of nitroarenes

Solid catalysts under the spotlight

A general soft-enveloping strategy in the templating synthesis of mesoporous metal nanostructures

Facile storage and release of white phosphorus and yellow arsenic

In situ quantitative single-molecule study of dynamic catalytic processes in nanoconfinement

Three-dimensional bicontinuous nanoporous materials by vapor phase dealloying

MXene molecular sieving membranes for highly efficient gas separation

Solid-state synthesis

Publisher Correction: Hierarchical self-entangled carbon nanotube tube networks

Three-Dimensional Bi-Continuous Nanoporous Gold/Nickel Foam Supported MnO2 for High Performance Supercapacitors

Ultrathin graphene oxide-based hollow fiber membranes with brush-like CO2-philic agent for highly efficient CO2 capture

Redox-switchable breathing behavior in tetrathiafulvalene-based metal–organic frameworks

Лента новостей (Journal of Porous Materials)

Synthesis and hydrogen storage properties of zirconium metal-organic frameworks UIO-66(H 2 ADC) with 9,10-anthracenedicarboxylic acid as ligand

Abstract

Zirconium metal-organic frameworks UIO-66(H2ADC) was synthesized with 9,10-anthracenedicarboxylic acid as ligand by the simple solution method (SS)and solvothermal reaction (S). The influence of different reaction conditions on the structure and properties of UIO-66(H2ADC) were investigated. The structures of samples UIO-66(H2ADC) were characterized by the powder X-ray diffraction, infrared spectroscopy and nitrogen sorption technique. UIO-66(H2ADC) and UIO-66 had the same face-centered cubic topology. When the feed ratio was 1.2:1 (metal:organic linker), the reaction temperature was 45 °C and reaction time was 12 h by the simple solution method (which was named UIO-66(H2ADC)-SS), UIO-66(H2ADC)-SS had the best crystallinity and BET specific surface area (432 m2/g) with average pore size of around 4.38 nm. And when at reaction condition was temperature of 85 °C, the feed ratio of 0.61:1(metal:organic linker) and time of 24 h by solvothermal reaction (denoted as UIO-66(H2ADC)-S), UIO-66(H2ADC)-S had the biggest BET specific surface area (772 m2/g) and had smaller average size of around 2.73 nm. The hydrogen storage properties of different samples were determined by hydrogen storage analyzer. UIO-66(H2ADC)-S and UIO-66(H2ADC)-SS hydrogen uptake capacity were 29.2 and 10.9 mg/g at 298 K, 5 MPa, respectively. When considering of unit the specific surface area adsorption UIO-66(H2ADC)-S and UIO-66(H2ADC)-SS were 0.0378 and 0.0252 mg/m2, but UIO-66 was 0.0233 mg/m2 ,which shown UIO-66(H2ADC) have good hydrogen uptake capacity. Interaction energy of UIO-66(H2ADC) and hydrogen was − 5.73 kJ/mol.

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Hierarchical ZSM-5 zeolite designed by combining desilication and dealumination with related study of n-heptane cracking performance

Abstract

The effect of the basic (NaOH) and/or acid (citric acid and EDTA-2Na) treatment of ZSM-5 zeolite has been studied comparing the structural and acidic features and their catalytic performance in n-heptane cracking. The properties of the catalysts have been elucidated using XRD, N2 low-temperature sorption, 27Al and 29Si NMR, pyridine adsorbed FTIR, NH3–TPD, SEM and TEM analysis. The results showed that the degree of desilication and dealumination of ZSM-5 zeolites was greatly dependent on the agents. NaOH obviously created new mesopores on parent ZSM-5 zeolites by desilication. Citric acid contributed to the removal of nonframework Al species, causing the increase of micropore surface area. EDTA-2Na promoted desilication and simultaneously converted part of removed framework Al species into nonframework Al species. The treatment of ZSM-5 combined with those three agents was very effective to obtain a hierarchical structure with partial breakdown of the crystallites and high acid amounts of both Brönsted and Lewis acid sites. Catalytic tests showed that the post-treated ZSM-5 catalysts had higher activity and stability than parent ZSM-5 catalyst at the same reaction temperature. The synergetic effect of Brönsted acid and Lewis acid of ZSM-5 catalyst (Z5-ACE) probably facilitated n-heptane conversion, while more clean micropore and newly created mesopores facilitated the slight increase of olefin selectivity and suppressing the formation of coke deposition in its inherent micropores to some extent.

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Wettability of porous anodic aluminium oxide membranes with three-dimensional, layered nanostructures

Abstract

The architecture-dependent wettability of three-dimensional (3D), porous anodic aluminium oxide (AAO) membranes with varying surface morphologies including hierarchical, mesh and honeycomb nanostructures is reported. The surface morphology and underlayer structure play different roles in regulating the wetting behaviour of the AAO membranes. For the mild AAO membranes, the wetting behaviour of the ultra-thin top layer is dominated by the surface morphology in which the water contact angles (WCAs) of the AAO membranes with hierarchical, mesh and honeycomb structures are approximately 113.7° ± 4.6°, 94.9° ± 0.7° and 98.8° ± 5.8°, respectively. The wetting behaviour of the 3D, layered AAO membranes is dominated by both the surface morphology and the underlayer structure. Notably, the WCA of the mild AAO membrane with a layered hierarchical structure increases in the second layer (increase in the hole density). The WCAs of the three kinds of layered hard AAO membranes decrease in the second layer (increase in the hole depth) and then decrease slowly or increase in the third transition layer (decrease in the hole density). The WCAs of all the AAO membranes decrease linearly at different rates with the formation of the ordered bottom layer. The above results can facilitate the engineering of nanostructures for controlling the surface wetting behaviour of materials and devices for applications in multiple fields.

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An efficient and controllable ultrasonic-assisted microwave route for flower-like Ta(V)–MOF nanostructures: preparation, fractional factorial design, DFT calculations, and high-performance N 2 adsorption

Abstract

With respect to different applications of metal–organic framework (MOF) in the medical, industrial and environmental fields, it is very important to choose a new structure that can be synthesized by fast, eco-friendly and affordable methods with distinctive properties so that the properties could be systematically controlled. In this study, new Ta–MOF nanostructures are synthesized by novel methods of microwave (Mw) and ultrasonic assisted microwave (UAMw) in environmental conditions. The final products are characterized by relevant techniques. Although in the both methods, the synthesized products have favourable properties; the use of the UAMw method would produce samples with distinct features such as high thermal stability of 240 °C, average particle size distribution (PSD) of 23 nm and significant specific surface area (SSA) of 2012 m2/g. For a better comprehension of the Ta–MOF formation, computational studies are performed using DFT calculations. In order to investigate the effect of the synthesis parameters on different features of the products, the fractional factorial design is used. The results of analysis of variance confirm that the parameters such as Mw power, Mw duration, ultrasonic temperature, ultrasonic power and ultrasonic duration have a significant effect on PSD and SSA of Ta–MOF samples. Due to the fractional factorial design of the experiments, response surface methodology would optimize the probability of producing samples with the small PSD of 15 nm and high SSA of 2588 m2/g; this desirable amount would provide situations to use these compounds in diverse fields.

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Chemical activation of mesoporous carbon with ultrahigh pore volume for highly supported adsorption of CO 2

Abstract

A novel mesoporous carbon (AMC850) with worm-like mesoporosity, very large BET surface area (2935 m2/g), and ultrahigh pore volume of 3.41 cm3/g was facilely synthesized from etching of the pristine mesoporous carbon (MC850) with sodium amide (NaNH2). The mesoporosity in the synthesized AMC850 was significantly expanded in comparison with pristine mesoporous carbon. The synthesized AMC850acts as an efficient support, could accommodate much more pentaethylenehexamine (PEHA) in comparison with the pristine MC850, giving PEHA@AMC850 composites. The resultant PEHA@AMC850 showed much improved property for the selective capture of CO2 in comparison with AMC850 (2.02 mmol/g vs. 0.73 mmol/g, at 75 °C). Thus, the PEHA@AMC850 composites showed promising application in the selective capture of CO2 from flue gas.

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Facile synthesis of diamine-functionalized hollow mesoporous silica sphere with self-templating method

Abstract

A new N-[3-(trimethoxysilyl)propyl]ethylenediamine-functionalized hollow mesoporous silica sphere (DA-HMSS) was synthesized by a two-step self-templating method, including hydrolysis and co-condensation of tetraethyl orthosilicate and N-[3-(trimethoxysilyl)propyl]ethylenediamine in the presence of ammonia solution and hexadecyltrimethylammonium bromide, following with hydrothermal incubation in pure water after the removal of hexadecyltrimethylammonium bromide. The successful formation of silica framework and incorporation of organic component in DA-HMSS were confirmed by Fourier transform infrared and solid-state 29Si cross-polarization/magic-angle-spinning nuclear magnetic resonance spectroscopic measurements as well as CHN elemental analysis. The hollow morphology of DA-HMSS was revealed by transmission electron microscopy, whereas its porosity was disclosed by nitrogen adsorption–desorption isotherm measurement. Furthermore, its carbon dioxide adsorption capability was also investigated.

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Opacified graphene-doped silica aerogels with controllable thermal conductivity

Abstract

In this work, we developed a new type of thermal insulation materials by combining the silica aerogel (SiO2) and graphene (G) followed by aging and supercritical drying. The effects of different G/SiO2 mass ratios on the microstructures and properties of opacified G/SiO2-x composite aerogels were investigated. The results showed that the graphene was well-distributed in the SiO2 matrix. Meanwhile, the opacified composite aerogels showed high-specific surface area (~ 1000 m2/g). Due to the unique bandgap feature and conjugated large π bond of graphene, the thermal insulation property of G/SiO2-x composite aerogels was enhanced in contrast with the pure SiO2 aerogel. Moreover, a possible mechanism of heat transfer was discussed to interpret the result.

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Inclusion complexes of eucalyptus essential oil with β-cyclodextrin: preparation, characterization and controlled release

Abstract

In this study, eucalyptus essential oil (EEO) was encapsulated into β-cyclodextrin (β-CD) by saturated aqueous solution method. The success of EEO encapsulation was confirmed by laser light scatting, scanning electron microscopy, Fourier transform infrared spectroscopy, differential scanning calorimeter and thermogravimetric analysis. Releasing characteristics experiments were carried out at various temperatures, relative humidity (RH), storage time and high temperature stability test. Release kinetics of EEO from the inclusion complexes was investigated by zero-order kinetics, first-order kinetics and Avrami’s equation. The result showed that the release model of EEO from inclusion complexes fitted better for Avrami’s equation. Kinetics analysis based on the Avrami’s equation revealed that the release of EEO was accelerated with the increases of RH and temperature. For storage time treatment, the volatilization of EEO was significantly inhibited after encapsulation. High temperature stability test further revealed that EEO was protected after having been encapsulated into β-CD. For all treatments, the release parameter n was between 0.5 and 1.0, which presenting a diffusion-limited and first-order mode. These results indicated that encapsulation enhanced the stability and prolonged the acting time of EEO, and the release rate of EEO can also be passively controlled by the ambient temperature, humidity and storage time.

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