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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)

Pore-size-tunable nitrogen-doped polymeric frameworks for high performance sodium ion storage and supercapacitors

Abstract

Sodium-ion batteries (SIBs) is considered as a promising alternative to lithium-ion batteries. Supercapacitors (SCs) are receiving great attention for their significantly higher power density than batteries and prolonged cycle life. Herein, SIBs and SCs based on N-doped amorphous multi-size pores dominated polymeric frameworks were fabricated and examined. The enlarged interlayer spacing and multi-size-pore dominated interconnected architecture with high specific surface area, high pore volume and high N content optimize the electrochemical performance of N-PPF-20. As an anode material, N-PPF-20 exhibited a sodium ion storage capacity of 432.2 mAh g−1 at a current density of 0.05 A g−1, while maintaining a reversible capacity of 61.1 mAh g−1 at an ultrahigh current density of 20 A g−1. Additionally, a specific capacity of 158.3 mAh g−1 at 1 A g−1 was obtained after 1000 cycles, indicating an excellent cycling stability. When tested as an electrode material for SCs, N-PPF-20 delivered a high specific capacitance of 438.7 F g−1 at 0.1 A g−1, and a specific capacitance of 111.2 F g−1 was achieved even at a high current density of 10 A g−1. Meanwhile, a long-term cycling life test demonstrated a specific capacitance of 120 F g−1 at an ultrahigh current density of 10 A g−1 after 10,000 cycles.

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Rapid and phase pure synthesis of microporous copper silicate (CuSH–1Na) with 12-ring channel system

Abstract

Phase pure sample of the microporous copper silicate CuSH–1Na has been obtained by simplified hydrothermal method without using additives (H2O2 and Na2HPO4). Ion exchange of Na+ by Cs+, Ca2+ and Sr2+ ions showed that the structure can suffer partial replacement of the charge compensating cations. Ion exchange with Cs+ resulted in distinct dehydration while the ion exchange with Sr2+ increased the total amount of water. Water content in the Ca-exchanged sample is comparable to the as-synthesized sodium phase. Raman spectroscopy revealed that the divalent cations as Ca2+ and Sr2+ induce stronger local structural deformations than the monovalent Cs+. These structural changes have been also followed by the refined lattice distortions. Magnetic analyses showed that CuSH–1Na presents a very weak ferromagnetic interaction along the Cu2+ chains with a nearly vanishing Curie–Weiss temperature. This magnetic coupling is associated with super-super-exchange interactions through Cu–Na–O–Na–Cu paths. Antiferromagnetic coupling, attributed to inter-chains super-super-exchange interactions, competes with the ferromagnetic one and prevails at the lowest temperature.

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Synthesis of carbon molecular sieve microspheres via amino phenolic resin as precursor formed from in-situ reaction composite micelles

Abstract

The carbon molecular sieve microspheres (CMSm) is one kind of porous carbonaceous materials. Owing to its high surface area and stability, CMSm have been attracted immense attention in various fields. In this study, the CMSm with tunable pore structure has been synthesized via self-assembling, in-situ reaction and soft-templating method in aqueous system. Meanwhile, the influence of carbonization temperature, heating rate, surfactant content and the amount of pore-forming agent (1, 3, 5-trimethylbenzene) on the morphology and pore properties of CMSm were studied. The result of nitrogen adsorption/desorption analysis indicates that the volume of the micropores increases as carbonization temperature increases, and generally decreases as the heating rate increases. The amount of surfactant and pore-forming agent have little influence on the volume of the micropores. It is also found that the CMSm have good hydrogen storage performance.

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Modification of metal organic framework HKUST-1 with CuCl for selective separation of CO/H 2 and CO/N 2

Abstract

Separation and recovery of CO from CO, H2, and N2 mixtures is quite imperative, due to the huge demands in chemical industry, aims of human health, and regulations of hydrogen fuel cell techniques. Cu(I) π complexation adsorbents show great potentials for CO adsorption. In this work, the typical MOF, HKUST-1 was modified with CuCl by the monolayer dispersion method for preparation of π complexation adsorbents. The resultant adsorbents were well characterized with XRD, and N2 adsorption−desorption isotherms (− 196 °C). These results suggest that CuCl has been successfully modified on HKUST-1. The CO, H2, and N2 adsorption performance of the adsorbents at 25 °C was tested as well. In addition, CO/H2 and CO/N2 selectivity was predicted by the ideal adsorbed solution theory (IAST). In general, the adsorbents modified with CuCl show better performance than pristine HKUST-1 on the CO separation from CO, H2, and N2 mixtures, including the CO adsorption capacity and the CO/H2, CO/N2 selectivity.

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Synthesis of carbon aerogels based on resorcinol–formaldehyde/hydroxyethyl cellulose/carbon fiber and its electrochemical properties

Abstract

Ternary carbon aerogels (CAs) were fabricated via a sol–gel process using resorcinol–formaldehyde (R–F), hydroxyethyl cellulose (HC) and carbon fibers (CFs) in the presence of an acid–base catalyst. The acid–base catalyst was composed of ascorbic acid (VC) and sodium carbonate. The products were carbonized at 900 °C in a nitrogen atmosphere. The effects of the acid–base catalyst on the structure and the electrochemical properties of the resulting CAs were studied. The textural and electrochemical properties were investigated by variable instruments (e.g. scanning electron microscopy (SEM), transmission electron microscopy (TEM), an ASAP 2420 surface-area analyzer, and a GAMRY Interface 1000 electrochemical workstation). These tests showed that, when the molar ratios of F/R, VC/R and Na2CO3/R were 2, 0.02 and 0.002, respectively, and the mass ratios of HC/R and CF/R were 0.09 and 0.005, respectively, the specific surface area of the resulting CA was 1071 m2 g−1 and its specific capacitance was 131 F g−1; both of these values are substantially better than those in prior reports.

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Mesoporous ZrO 2 –Al 2 O 3 (ZA) mixed metal oxide as an efficient and reusable catalyst for the liquid phase O -methoxymethylation reaction under solvent free conditions

Abstract

Mixed metal oxide based solid acids like ZrO2–Al2O3 (ZA) with Al2O3 different loadings (2, 4, 6, 8 and 10 mol%) were prepared by wet impregnation method and characterized by PXRD, NH3-TPD, BET, ICP-OES, SEM, and TEM techniques. These solid acids were evaluated for their catalytic activity in the synthesis of a series of O-methoxymethylated products under solvent-free conditions at a moderate temperature in shorter reaction time (~20 min). This is achieved by various substituted alcohols and dimethoxy methane in good yields. Solid acids containing ZA used in this study exhibited good catalytic activity in the reaction. In case of 6 mol% ZA which has highest surface acidity, surface area and catalytically active tetragonal phase was found to be highest active in the O-methoxymethylation reaction up to ~99% yield. These catalysts were found to be reactivable and reusable.

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Direct synthesis of nano titania on highly-ordered mesoporous SBA-15 framework for enhancing adsorption and photocatalytic activity

Abstract

This paper reports the synthesis of TiO2-containing mesoporous catalysts for effectively enhancing the adsorption and photocatalytic activity. The factors that affect the photocatalytic activity of catalyst composites, including types of silica support, TiO2 content, calcination temperature, and catalyst mass, were examined in this study. The samples were characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, and surface area analysis. The experimental results showed that incorporating TiO2 nanoparticles into silica gel or SBA-15 frameworks could enhance the photodegradation rate more effectively than pure TiO2. The TiO2/SBA-15 sample displayed much higher adsorption and photocatalytic activity levels than did TiO2/silica-gel. The pore volume and pore size of TiO2/SBA-15 were as high as 1.317 cm3/g and 7.51 nm, respectively, which exceeded those of TiO2/silica-gel (0.437 cm3/g and 3.68 nm, respectively). The rate constants of photocatalysis were determined. The photodegradation rate of the catalyst increased with decreasing TiO2 content and increasing calcination temperature. The proposed method of preparing mesoporous photocatalysts is simple and suitable for mass production.

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Cascade use of bamboo as raw material for several high value products: production of xylo-oligosaccharide and activated carbon for EDLC electrode from bamboo

Abstract

The cascade use of bamboo as the raw material for high-value products, that is, the production of xylo-oligosaccharide and the preparation of activated carbon for EDLC electrode, was proposed as an economically effective use of bamboo in this study. Xylo-oligosaccharides, such as xylobiose and xylotriose, were successfully produced from bamboo in a water solution by a hot compressed water process. The solid residue of bamboo after the treatment of the hot compressed water was carbonized at 400–800 °C, then activated with KOH. The KOH activation was effective for the preparation of activated carbon having a high BET specific surface area of ca. 2600 m2 g−1 from the solid residue. The amount of ash drastically decreased by the hot compressed water treatment, which should be an advantage as the precursor for EDLC electrodes. The capacitance values measured in a 1 M H2SO4 aqueous solution of the activated carbon derived from the solid residue compared well with those from the bamboo.

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