Preparation and characterization of ordered porous carbons for increasing hydrogen storage behaviors

We prepared ordered porous carbons (PCs) by using a replication method that had well-organized mesoporous silica as a template with various carbonization temperatures in order to investigate the possibility of energy storage materials. The microstructure and morphologies of the samples are characterized by XRD, TEM, and FT-Raman spectroscopy. N₂ adsorption isotherms are analyzed by the t-plot method, as well as the BET and the H–K method in order to characterize the specific surface area, pore volume, and pore size distribution of the samples, respectively. The capacity of the hydrogen adsorption of the samples is evaluated by BEL-HP at 77 K and 1 bar. From the results, we are able to confirm that the synthesis of the samples can be accurately governed by the carbonization temperature, which is one of the effective parameters for developing the textural properties of the carbon materials, which affects the behaviors of the hydrogen storage.     

Steam-carbon gasification catalyzed by calcium: Assessment of the porous structure of active carbons from plum stones and synthetic active carbons

A need for an elaboration of the methods for synthesis and characterization of activated carbons with a requisite porous structure has existed for a long time. One of the methods giving possibility for creating controlled mesopore and micropore structures deals with the steam gasification of various carbon materials. In this work the effects of calcium catalyst on the catalytic steam gasification of active carbons from plum stones and porous polymers are presented. Determination of micropores capacity and specific adsorption in mesopores have been performed by means of the _s method, but adsorption on the heterogeneous solids was described by the integral equation with various local isotherms. This equation has been solved by the regularization method. Based on this method the changes in structural parameters of active carbons depending on the amount of calcium catalyst were estimated.Nomenclature d width of slit-like micropore - F(x) distribution function of the half-width - p vapor pressure of sorbate - p/p _N relative pressure - PSAC Plum Stone Active Carbon - average pore radius, nm - S ₁ relative limit of the validity of experimental point on the adsorption isotherm in the computations by means of regularization method - SAC Synthetic Active Carbon - S _BET specific surface area calculated by means of BET method, m²/g - S _mes mesopore surface area, m²/g - S _mic micropore surface area, m²/g - T absolute temperature, K - V _mes sorption capacity of mesopores, cm³/g - V _mic sorption capacity of micropores, cm³/g - V _p sorption capacity of pores, cm³/g - w/w weight in weight concentration - x half-width of slit-like micropore, nm - x ₁ maximum of half-width of micropore slit, nm - average half-width of slit-like micropore, nm - X _min-X _max integration limits of thex Greek Letters Greek Letters variance of average half-width of slit-like micropore, nm² - local relative filling of micropores - total relative filling of micropores     

Estimation of the porous structure of active carbons

Active carbons from apricot, plum, peach, and grape stones were prepared. The analysis of adsorption isotherms of benzene vapor showed that the active carbons obtained from fruit stones have highly homogeneous microporous structures withW ₀ 0.30 cm³ g^–1,E ₀ 24.5 kJ mol^–1, andx ₀ 0.42 nm, and they contain ultramicropores along with micropores.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1934–1936, October, 1995.This study was financially supported by the Russian Foundation for Basic Research (Project No. 94-03-09550).     

超高比表面积氮掺杂多孔碳材料的制备及其超级电容性能

以蔗糖为碳源、尿素为氮源、草酸钾为活化剂,通过简单的研磨和高温碳化制备了具有超高比表面积(大于3 000 m²·g^-1)的氮掺杂多孔碳材料。采用多种手段对多孔碳材料的微观形貌、比表面积、孔结构和表面氮物种进行了表征,探究了不同温度下草酸钾和尿素对碳材料的比表面积、氮含量和超级电容性能的影响。结果表明,仅使用草酸钾作为活化剂制备的碳材料KC-800的比表面积为1 114 m²·g^-1,而同时使用草酸钾和尿素制备的样品KNC-800的比表面积高达3 033 m²·g^-1。在以6.0mol·L^-1 KOH为电解液的三电极体系中,当电流密度为0.5 A·g^-1时,KNC-800的比电容为405 F·g^-1,而KC-800的比电容仅为248 F·g^-1。这表明草酸钾和尿素的加入显著提高了多孔碳材料的比表面积和超级电容性能。电容贡献分析表明,KNC-800的双电层电容值和赝电容值均...     

超高比表面积氮掺杂多孔碳材料的制备及其超级电容性能

以蔗糖为碳源,尿素为氮源,草酸钾为活化剂,通过简单的研磨和高温碳化制备了具有超高比表面积(大于3 000 m²·g^-1)的氮掺杂多孔碳材料。采用多种手段对多孔碳材料的微观形貌、比表面积、孔结构和表面氮物种进行了表征,探究了不同温度下草酸钾和尿素对碳材料的比表面积、氮含量和超级电容性能的影响。结果表明,仅使用草酸钾作为活化剂制备的碳材料KC-800 的比表面积为 1 114 m2·g^-1,而同时使用草酸钾和尿素制备的样品 KNC-800 的比表面积高达 3 033 m²·g^-1。在以 6.0mol·L^-1 KOH 为电解液的三电极体系中,当电流密度为 0.5 A·g^-1时,KNC-800 的比电容为 405 F·g^-1,而 KC-800 的比电容仅为248 F·g^-1。这表明草酸钾和尿素的加入显著提高了多孔碳材料的比表面积和超级电容性能。电容贡献分析表明,KNC-800的双电层电容值和赝电容值均高于KC-800。KNC-800在电流密度为0.5 A·g^-1时经过10 000次循环后仍能保持98.3%的初始比电容,表现出优异的循环性能。     

Prediction of the micropore structure parameters and adsorption properties of activated carbons

A regularity govering variations of volume and linear size of micropores in carbon adsorbents during their vapor-gas activation was found. A parameter was proposed that characterizes the degree of development of the micropore system in activating carbons and an initial carbonized material. The parameter is defined as the number (or surface area) of micropores in the volume unit of the micropore zones. This parameter allows one to rationalize the choice of carbonized materials for the preparation of activated carbons with specified adsorption properties and to establish the range of activation beyond which the structure of the micropores loses stability. Furthermore, the parameter serves to predict how activation affects micropore structure parameters and adsorption properties of carbons. This in turn indicates the optimal degrees of microporosity of carbons needed to attain required adsorption properties.     

低成本硫掺杂多孔碳材料的制备及其超级电容性能

以廉价的胶态二氧化硅为模板,蔗糖为碳源,硫酸为预碳化试剂和硫源,通过硬模板法制备了相对廉价的硫掺杂多孔碳(SSC-T,T℃代表碳化温度)材料。采用多种表征方法对多孔碳材料的微观形貌、孔道结构、比表面积和表面硫物种进行了表征,探究了硫酸和碳化温度对多孔碳材料的微观形貌、孔道结构和比表面积的影响。结果表明,碳化温度对碳的孔结构、比表面积和硫元素的含量有显著的影响,其中900℃碳化得到的样品SSC-900具有最大的比表面积、孔体积和比电容,远高于未加入硫酸制备的碳材料SC-900,表明硫酸的加入可以提高碳材料的比表面积、孔体积,进而提高碳材料的比电容。与昂贵的有序介孔碳CMK-3相比,SSC-900具有成本更低、孔径更大和电容性能更好的优点。在以6.0 mol·L^-1 KOH为电解质的三电极体系中,在0.5 A·g^-1的电流密度下,SSC-900的比电容可以达到357 F·g^-1,而SC-900和CMK-3的比电容分别仅为152和266 F·g^-1。电容贡献分析表明,SSC-900的双层电容值和赝电容值均高于SC-900。此外,SSC-900在0.5 A·g^-1的电流密度下循环10 000次后仍能保持98.4%的初始比电容。     

低成本硫掺杂多孔碳材料的制备及其超级电容性能

以廉价的胶态二氧化硅为模板,蔗糖为碳源,硫酸为预碳化试剂和硫源,通过硬模板法制备了相对廉价的硫掺杂多孔碳(SSC-T,T℃代表碳化温度)材料。采用多种表征方法对多孔碳材料的微观形貌、孔道结构、比表面积和表面硫物种进行了表征,探究了硫酸和碳化温度对多孔碳材料的微观形貌、孔道结构和比表面积的影响。结果表明,碳化温度对碳的孔结构、比表面积和硫元素的含量有显著的影响,其中900℃碳化得到的样品SSC-900具有最大的比表面积、孔体积和比电容,远高于未加入硫酸制备的碳材料SC-900,表明硫酸的加入可以提高碳材料的比表面积、孔体积,进而提高碳材料的比电容。与昂贵的有序介孔碳CMK-3相比,SSC-900具有成本更低、孔径更大和电容性能更好的优点。在以6.0 mol·L^-1 KOH为电解质的三电极体系中,在0.5 A·g^-1的电流密度下,SSC-900的比电容可以达到357 F·g^-1,而SC-900和CMK-3的比电容分别仅为152和266 F·g^-1。电容贡献分析表明,SSC-900的双层电容值和赝电容值均高于SC-900。此外,SSC-900在0.5 A·g^-1的电流密度下循环10 000次后仍能保持98.4%的初始比电容。     

Preparation and evaluation of nano-hydroxyapatite/poly(styrene-divinylbenzene) porous microsphere for aspirin carrier

A novel vehicle for the delivery of aspirin (ASA) was prepared from porous nano-hydroxyapatite/poly(styrene-divinylbenzene) [nano-HAP/P(St-DVB)] composite microspheres by grafting nano-HAP [Ca10(PO4)6(OH)2] onto porous P(St-DVB) microspheres. Four types of porous composite microspheres were prepared, each with different nano-HAP contents. The ASA-loaded composite microspheres prepared with 10% and 15% nano-HAP (mass ratio) exhibited excellent buoyancy with relatively short instantaneous floating time (within 10 min) and a long sustained floating time (12 h) in simulated gastric juice. They also offered good sustained release of ASA (up to 8 h). Furthermore, these composite microspheres displayed good buffering capacity that prevented the buildup of acidity caused by hydrolysis of ASA, keeping the pH of gastric juice within the normal range (pH 0.9 to 1.5). The results showed that porous nano-HAP/P(St-DVB) composite microspheres prepared with 10% and 15% nano-HAP could be used as a novel drug carrier for ASA, providing a sustained release dose without leading to stomach irritation, a side effect that is often associated with ASA medication.     

硼、氮共掺杂多孔碳的制备及其超电容性能

分别以含氮菲咯啉、四硼酸钾和醋酸锌为碳源、活化剂和模板,制备了B、N共掺杂多孔碳(BN-PC),并探究模板质量对BN-PC结构和储电性能的影响。当醋酸锌质量为5g时,所得BN-PC₅中B、N杂原子含量分别为 20.21%、18.29%。电化学测试结果表明,以6 mol·L^-1 KOH为电解液,BN-PC₅电极展现出高的比电容(在0.05 A·g^-1电流密度下为255 F·g^-1)、优异的倍率性能(在20A·g^-1电流密度下为188F·g^-1)和卓越的循环稳定性(在5 A·g^-1的电流密度下循环10 000次比电容保持率为97%)。以3 mol·L^-1 ZnSO₄为电解液,在平均功率密度为56W·kg^-1时,BN-PC₅电容器的能量密度可达27Wh·kg^-1。     

硼、氮共掺杂多孔碳的制备及其超电容性能

分别以含氮菲咯啉、四硼酸钾和醋酸锌为碳源、活化剂和模板,制备了B、N共掺杂多孔碳(BN-PC),并探究模板质量对BN-PC结构和储电性能的影响。当醋酸锌质量为5 g时,所得BN-PC₅中B、N杂原子含量分别为20.21%、18.29%。电化学测试结果表明,以6 mol·L^-1KOH为电解液,BN-PC₅电极展现出高的比电容(在0.05 A·g^-1电流密度下为255 F·g^-1)、优异的倍率性能(在20 A·g^-1电流密度下为188 F·g^-1)和卓越的循环稳定性(在5 A·g^-1的电流密度下循环10 000次比电容保持率为97%)。以3mol·L^-1ZnSO₄为电解液,在平均功率密度为56 W·kg^-1时,BN-PC₅电容器的能量密度可达27 Wh·kg^-1。     

Preparation of biomass-activated porous carbons derived from torreya grandis shell for high-performance supercapacitor

Journal of Solid State Electrochemistry - In this paper, we reported a novel biomass-derived porous carbon from torreya grandis shell for the first time by means of carbonization and KOH activation...     

Synthesis and electrochemical performance of hierarchical porous carbons with 3D open-cell structure based on nanosilica-embedded emulsion-templated polymerization

A novel synthesis of hierarchical porous carbons （HPCs）with 3D open-cell structure based on nanosilica- embedded emulsion-templated polymerization was reported. An oil-in-water emulsion containing SiO2 colloids was fabricated using liquid paraffin as an oil phase, resorcinol/formaldehyde and silica sol as an aqueous phase, and Span 80/Tween 80 as emulsifiers. HPCs with macropore cores, open meso/ macropore windows, and abundant micropores were synthesized by the polymerization and carbonization of the emulsion, followed by scaffold removal and further KOH activation. A typical HPCs sample as supercapacitor electrode shows the charge/discharge capability under large loading current density （30 A/g） coupling with a reasonable electrochemical capacitance in KOH electrolyte solution.     

Hierarchical porous nanofibers of carbon@nickel oxide nanoparticles derived from polymer/block copolymer system

The triblock copolymer (PAA-b-PAN-b-PAA) is prepared by reversible addition-fragmentation chain-transfer polymerization, and then blended with polymer (PAN) and metal hydroxide (Ni(OH)₂) as a precursor for heat-treatment. A composite material of hierarchical porous nanofibers and nickel oxide nanoparticles (HPCF@NiO) is prepared by electrospinning combined with high-temperature carbonization. The effects of the ratio of PAA and PAA-b-PAN-b-PAA on the internal structure of nanofibers and their electrochemical properties as positive electrode materials are investigated. The experimental results show that when the ratio of PAA to PAA-b-PAN-b-PAA is 1.3 to 0.4, it has good pore structure and excellent electrochemical performance. At the current density of 1 A/g, the specific capacitance is 188.7 F/g and the potential window is −1 V to 0.37 V. The asymmetric supercapacitor assembled with activated carbon as the negative electrode materials has a specific capacitance of 21.2 F/g in 2 mol/L KOH and a capacitance retention of 85.7% after 12,500 cycles at different current density.     

Preparation and drug release behavior of temperature-responsive mesoporous carbons

A temperature-responsive composite based on poly (N-isopropylacrylamide) (PNIPAAm) and ordered mesoporous carbons (OMCs) has been successfully prepared by a simple wetness impregnation technique. The structures and properties of the composite were characterized by infrared spectroscopy (IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), N₂ sorption, thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). The results showed that the inclusion of PNIPAAm had not greatly changed the basic ordered pore structure of the OMCs. Ibuprofen (IBU) was selected as model drug, and in vitro test of IBU release exhibited a temperature-responsive controlled release delivery.     

Preparation and characterization of porous titania-grafted poly(styrene-divinylbenzene)/maleic anhydride nanocomposite microspheres

Mesoporous titania-grafted poly(styrene-divinylbenzene)/maleic anhydride [P(St-DVB)/MA] nanocomposite microspheres were prepared by an open ring reaction method.The titania nanoparticles were first modified by attachment of amino groups to their surface to prevent particle aggregation,and to allow the nanoparticles to covalently bond the polymer microspheres,the surface of which was modified by attachment of MA functional groups to enable the polymer to retain their porous structures and to react with the a...     

Preparation and structure characterization of carbons prepared from resorcinol-formaldehyde resin by CO2 activation

In this work, carbon xerogels with a high pore volume and surface area (up to 2.58 cm³/g and 3200 m²/g respectively) have been synthesized using the sol-gel polycondensation of resorcinol (R) with formaldehyde (F) in a basic medium of monoethanolamine (MEA), followed by drying and pyrolysis. This medium (MEA) has not been used in previous investigations. The effect of activation with CO₂ on the pore size distribution and the chemical functional groups has been investigated using N₂ (77 K) adsorption, FTIR and elemental analysis techniques. A series of experiments has been conducted to investigate the effect of activation time and activation temperature. Activation of the samples was carried out at 850, 900 and 980 °C for times ranging from one to three hours. Within the range of activation conditions, an increase in activation time at 850 °C results in a continuous steady rise of the BET surface area and total pore volume. However, at the two higher temperatures, the surface area shows a maximum when plotted against activation time. FT-IR results show that the use of MEA as a catalyst leads to the formation of nitrogen functional groups in the surface of the resin.     

Multiwavelength Raman spectroscopy analysis of a large sampling of disordered carbons extracted from the Tore Supra tokamak

Disordered carbon often exhibit a complex Raman spectrum, with four to six components. Here, a large variety of disordered carbons, forming a collection of samples with a great variety of structures, are analyzed using multi-wavelength Raman microscopy (325.0, 514.5, 785.0 nm). They allow us to extend Raman behaviour known for nano-crystalline graphite to amorphous carbons, (dependence with the excitation wavelength) and other known for amorphous carbons to nano-crystalline graphite, (differentiation of the smallest cluster size probed using different excitation wavelengths). Experimental spectra were compared to simulated spectra, built using known laws, to evidence a new source of broadening.     

Preparation and characterization of templated porous carbons from sucrose by one-pot method and application as a CO2 adsorbent

The templated porous carbons were prepared from sucrose by one-pot method. In this method in which the pre-synthesis of the hard template is eliminated, the porous carbons were produced by organic-inorganic self-assembly of sucrose, tetraethyl ortosilicate (TEOS), Pluronic P123 and n-butanol in an acidic medium, and subsequent carbonization. The synthesis parameters such as sucrose amount, TEOS molar ratio and carbonization temperature were evaluated for describing their effects on the pore structures of the synthesized carbons. The prepared porous carbons were characterized by N₂ adsorption, thermogravimetric analysis (TGA), Raman spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) techniques. The carbon dioxide adsorption uptakes of the obtained porous carbons were determined at 1 bar and 273 K. The templated carbon obtained with the lowest TEOS molar ratio exhibited the highest BET surface area of 1289 m²/g and micropore volume of 0.467 cm³/g, and showed the highest CO₂ uptake of 2.28 mmol/g.     

Preparation of a new hydrophilic copolymer from a polylactone and the structure analyses

A new hydrophilic copolymer having three kinds of hydroxyl groups, i.e. primary OH on -hydroxy allyl alcohol component, secondary OH on cyclic hemiacetal component and tertiary OH on -hydroxy acrylate component, was prepared by reducing a ‘polylactone’, poly(1-oxa-2-oxobutane-1,4:3,3-tetrayl), with NaBH₄ in mixed solvents containing an alcohol. The structural analyses were performed by the solution ¹H NMR and the solid state ¹³C NMR spectroscopies of the reduced samples. The composition of the three components turned out to be variable to the alcohol species used for the mixed solvent.