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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)

Effect of preparation conditions of benzene bridged Ti incorporated periodic mesoporous organosilicas on selectivity improvement of cyclohexene epoxidation

Abstract

Benzene bridged Ti incorporated periodic mesoporous organosilicas (Ti-PMOs) was prepared following an in situ hydrothermal method by using P123 as a structure directing agent in acidic condition, tetrabutyl titanate (TBOT) as titanium source, tetraethoxysilane (TEOS) as inorganic Si-source and 1, 4-bis(triethoxysilyl)benzene (BTEB) as organic Si-source. The effects of preparation conditions of Ti-PMOs, mole ratio of TEOS/BTEB and ageing time, on the catalytic performance for the cyclohexene epoxidation with tertbutyl hydroperoxide as an oxidant agent were investigated. By means of a variety of characterized method, the results showed that the proper mole ratio of TEOS/BTEB was 3:1, which was favor of maintaining good mesoporous structure, ageing time of preparation mixture solution was a key factor to improve the catalytic performance of Ti-PMOs. NH3-TPD indicated that sample prepared at ageing time 48 h had more readily exposed active titanium site, which significantly improve the selectivity of cyclohexene oxide to 97.7% from 37.7% at 24 h ageing time. The hydrophobic group of benzene bridged on the pore wall was benefit for the approach of cyclohexene and formation of the active tetravalent titanium.

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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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Solvothermal synthesis of porous conjugated polymer with high surface area for efficient adsorption of organic and biomolecules

Abstract

Aimed to prepare high efficient dye sorbent and control water pollution, herein we utilized solvothermal method to synthesize porous polyimide (PI) polymer with a large surface area using DMSO as solvent. Unlike the solid-state thermal polymerized PI with low surface area of 5 m2g−1, this PI material prepared in DMSO solvent possessed a large surface area of 430 m2g−1, which was beneficial for adsorption of organic dye in waste water, achieving a max MO adsorption of 200 mg g−1 three times higher than that of multiwalled carbon nanotube. The adsorption kinetics of dye molecules on PI was investigated in detail and the R2 value of 0.99071 for pseudo-second-order model confirms the adsorption was fitted best with Langmuir isotherm.

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Study on the preparation of ordered mesoporous carbon-based catalyst from waste microalgal biomass for the synthesis of biokerosene

Abstract

Investigation on preparation of novel ordered mesoporous carbon-based catalyst (MCC catalyst) containing super-acid sites from waste microalgal biomass was established. The waste microalgal biomass was partially carbonized at 400 °C for 2 h obtaining biochar; then the obtained biochar was introduced to a sulfonation process using concentrated sulfuric acid. The sulfonation was established at 150 °C for 15 h producing sulfonated biochar. The MCC catalyst was prepared through condensation–evaporation method in an alkaline media containing cetyltrimethylammonium bromide (CTAB) as structure directing agent. The parameters of the condensation including time of evaporating and CTAB content were investigated while fixing temperature at 90 °C during the process. A special hydrothermal treatment was also applied to the preparation of the MCC catalyst in order to expand its mesopores for more convenient with large molecule diffusion. The catalyst activity was well demonstrated by converting linseed oil to biokerosene which could be used as biokerosene—component for blending with aviation fuels. The MCC catalysts were characterized by X-ray diffraction, infrared spectroscopy, energy dispersive X-ray, scanning electron microscopy, transmission electron microscopy, nitrogen adsorption–desorption method and ammonia-temperature programmed desorption techniques. The biokerosene composition was determined by gas chromatography–mass spectroscopy method.

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Synthesis of a highly hydrophobic silica mesostructure by a modified co-condensation procedure and evaluation of its drug release capability

Abstract

A highly hydrophobic silica mesostructure was synthesized by a modification on the conventional co-condensation procedure that involved the partial substitution of hexadecytltrimethylammonium, used as mesostructure directing agent, by hexadecyltrimethoxysilane. That modification allowed the production of a highly ordered hexagonal silica mesostructure with the mesopores partially filled with high amounts of hexadecyl chains, covalently bonded to inorganic framework. After extracting the reminiscent template molecules, ibuprofen was loaded into the mesostructure in order to evaluate its drug release properties. The drug loading amount (21 wt%) was comparable to the one reported for MCM-41 with grafted propylamine groups (25 wt%), indicating that C16-chains were not fully compacted occluding the pores. A slow ibuprofen release was observed in simulated body fluid (pH 7.2) by a process controlled by an anomalous transport with contribution of diffusional and relaxational components, according to the Korsmeyer-Peppas kinetics model. That hydrophobic mesostructure produced has the potential of being use as a carrier for low water soluble drugs with an extended delivery effect, but without the disadvantages of co-releasing toxic surfactant molecules or the need of non-toxic specific templates to be prepared.

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Preparation of effective Ag-loaded zeolite antibacterial materials by solid phase ionic exchange method

Abstract

Ag-loaded antibacterial zeolite materials were prepared by a solid phase ionic exchange approach with small NaA zeolite crystals synthesized by sol–gel method as carrier, NH4NO3 and AgNO3 as raw materials. The influence of AgNO3 amount, reaction temperature, and reaction time on silver load in the zeolite was investigated. The phase composition and morphology of the Ag-loaded zeolite were also characterized. In addition, the antibacterial activity, sustained-release performance, and anti-tarnish property of the Ag-loaded zeolite were studied. The results show that the Ag-loaded zeolite was synthesized under optimum conditions. The amount of silver load in the zeolite was up to 23.45% (mass ratio). The minimum inhibitory concentration value (MIC value) was 9.17 ppm, and the diameter of inhibition zone for Escherichia coli was 16.3 mm. The MIC value was 12.50 ppm, and the diameter of inhibition zone for Staphylococcus aureus was 14.5 mm. Furthermore, the Ag-loaded zeolite materials demonstrate good sustained-release performance and anti-tarnish property.

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Three-dimensional porous carbon aerogels from sodium carboxymethyl cellulose/poly(vinyl alcohol) composite for high-performance supercapacitors

Abstract

Three-dimensional interconnected porous carbon aerogels were successfully prepared by the pyrolysis of sodium carboxymethyl cellulose/poly(vinyl alcohol) composite using borax as a cross-linking agent. After sol–gel, freeze-drying, carbonization and KOH-activation treatments, the as-obtained carbon aerogels exhibited high specific surface areas (SSAs) and excellent electrochemical performance. The optimal sample showed a high SSA of up to 601.4 m2/g with a total pore volume of 0.38 cm3/g. The aCA-3 sample exhibited an excellent capacitance of 182.8 F/g at a current density of 0.5 A/g, within a potential window of − 1.0 to 0.0 V in a 6 M KOH electrolyte solution. In addition, the aCA-3 electrode showed excellent cyclability with 96.2% capacitance retention efficiency at 2 A/g current density after 2000 cycles of charge/discharge. These easily prepared, well-structured and high-performance carbon aerogels have significant potential applications in advanced electronic devices and energy storage systems.

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Effect of meso- and micropore structures on the hydrogen storage properties of nanoporous carbon materials

Abstract

We report on the pore structure and hydrogen storage properties of nanoporous carbon (NPC) prepared by KOH activation of rice husk ash. The specific surface area of the NPC increased from 220 to 2770 m2/g with an increase in KOH/rice husk ash weight ratio from 1:1 to 7:1. In addition, the micropore volume of the NPC increased from 0.08 to 0.73 cm3/g with an increase in KOH quantity. Furthermore, the mesopore volume also increased from 0.08 to 2.17 cm3/g. Results of pore size distribution studies indicated NPC pore size widening from the micropore to the mesopore scale with the addition of further KOH. The stored hydrogen content of the NPC therefore increased with the development of the pore structure. From these results, we propose that this change in pore size is responsible for the increase in stored hydrogen content in NPCs.

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