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采用原位悬浮聚合和熔融加工制备了不同纳米水滑石含量的偏氯乙烯-丙烯酸甲酯(VDC-MA)共聚物/纳米水滑石复合材料,并通过高温炭化和模板消除得到多孔炭材料。采用电镜、X射线衍射、N2吸脱附法表征了复合材料和多孔炭的结构。结果表明,纳米水滑石含量≤6.25%(质量)时,纳米水滑石基本以初级粒子均匀分散在VDC-MA共聚物基体中,并在炭化过程中转化为金属氧化物;金属氧化物可经酸洗去除,起到模板致孔作用;同时VDC-MA共聚物炭化过程形成大量微孔,因此得到的多孔炭具有微孔和中孔分布。当炭化温度较低时(600~700℃)相似文献
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《高校化学工程学报》2015,(4)
通过直接碳化由可逆加成-断裂链转移(RAFT)活性自由基聚合制备的聚偏氯乙烯-b-聚乙二醇-b-聚偏氯乙烯共聚物(PVDC-b-PEG-b-PVDC),制备了微孔-中孔复合多孔炭,并对其电化学性能进行了研究。凝胶渗透色谱仪表征表明通过RAFT聚合制得的PVDC-b-PEG-b-PVDC的分子量较高(MnGPC7000 g?mol-1)、分子量分布较窄(PDI1.5)。采用热重分析、扫描电镜、N2等温吸脱附法表征了嵌段共聚物的热分解特性和多孔炭的结构,发现PEG链段可完全热分解而具有形成中孔的模板作用,PVDC链段热分解形成含微孔的炭骨架,最终形成兼有微孔和中孔、最大比表面积达1242m2?g-1、孔容达0.49 cm3?g-1的多孔炭。电化学测试表明制备的多孔炭的电化学特性良好,当电流密度为0.5 A?g-1时,PVDC-b-PEG4k-b-PVDC基多孔炭的比电容达到157 F?g-1,显著优于文献报道的PVDC基多孔炭的比电容。 相似文献
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通过简单的无机盐磷酸氢二铵催化稳定化、炭化及不同碱炭比KOH活化制备了高比表面积的多孔淀粉基炭微球材料。采用电子扫描显微镜(SEM)、高分辨透射电子显微镜(HRTEM)及N2吸脱附测试对实验所制得的炭微球样品的形貌及孔结构进行了分析。结果表明:不同KOH碱炭比制备的多孔淀粉基炭微球材料具有较大的比表面积(﹥2 300 m2/g),且均含有大量的大孔和微孔,在6 mol/L的 KOH电解液对称的双电层电容器中多孔淀粉炭材料表现出优异的电化学性能,在100 A/g的大电流密度下,炭微球电极材料具有最大的质量比电容高达248 F/g。 相似文献
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采用可逆加成-断裂链转移(RAFT)活性自由基聚合制备了聚苯乙烯-b-聚偏氯乙烯-b-聚苯乙烯嵌段共聚物(PS-b-PVDC-b-PS),以此嵌段共聚物为碳前驱体,直接碳化制备微孔-中孔复合多级多孔炭。采用凝胶渗透色谱仪和核磁共振仪表征了嵌段共聚物结构,表明通过RAFT聚合可制得分子量较高(MnGPC >6000 g·mol-1)和分子量分布较窄(PDI<1.5)的PS-b-PVDC-b-PS。采用热重分析表征嵌段共聚物热解特性,采用扫描电镜、N2吸脱附表征多孔炭形貌和孔隙结构。结果表明嵌段共聚物同时具有PVDC和PS链段的热失重峰,PS链段可完全热解而具有形成中孔的模板作用,PVDC链段热降解形成含微孔的炭骨架,最终形成兼有微孔和中孔的多级多孔炭;随着PS嵌段含量的增加,嵌段共聚物的成炭率逐渐降低,孔隙尺寸逐渐增大;当PS/PVDC聚合度比为4.3时,多孔炭的比表面积、中孔率和平均孔径达到最大,分别为839 m2·g-1、54%和2.02 nm。 相似文献
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能源消费增加促使绿色能源开发成为趋势,同时推动能源存储系统快速发展,超级电容器以高功率密度和长循环寿命的优势得到广泛关注,其中电容炭材料逐渐成为研究热点。用来源广泛、有可再生性、价格低廉、绿色环保的生物质制备超级电容器用多孔炭材料,在开发绿色能源的同时解决了能源存储问题。多孔炭材料结构调控与性能完善是提高超级电容器性能的重要途径之一。综述了生物质衍生多孔炭材料及其在超级电容器领域的应用,按原料来源(植物、动物和微生物)及材料维度(0D、1D、2D和3D)的分类体系,多孔炭材料制备方法及技术现状。将多孔炭的制备分为炭化和活化,简述了炭化与活化机理、活化方式选择和常见活化剂特性,但生物质衍生多孔炭材料制备过程中影响因素多,且性能不及传统煤基碳材料,需进行多方面设计优化,包括选择生物质前驱体、合理使用炭化技术、调控活化过程各影响因素和选择改性过程中掺杂物等。基于在超级电容器领域的应用需求,重点探讨生物质多孔炭材料优化方式,包括孔结构调控、表面元素掺杂及与石墨烯复合形成新型炭材料等。梳理多孔炭材料用于超级电容器中时的难题与重点,通过寻找多孔炭材料在高比表面积、均匀孔隙分布和高导电性3方面的最优... 相似文献
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本文综述了国内外在调控多孔炭材料孔径分布,特别是提高其中孔率方面的研究进展,着重介绍了催化活化、界面活化、混合聚合物炭化、有机凝胶炭化、铸型炭化等孔径调控技术及其孔结构形成机理。为控制多孔炭材料的孔径大小和分布,提出其中孔容积(率)和吸附性能提供了理论和实验依据。 相似文献
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Emerging applications such as gas storage require porous carbon materials with tailored structural and surface properties. Template synthesis approach to porous carbons offers opportunities for tailoring these properties. In this study, ammonium-form zeolite Y (NH4Y) was used as a template and furfuryl alcohol (FA) was employed as a carbon precursor to prepare microporous carbons by simple impregnation method. The effects of synthesis conditions such as carbonization temperatures and heating rates on the pore structure of the microporous carbons were investigated. The thermal behaviors of FA-NH4Y mixtures and zeolite/carbon composites were studied by thermogravimetric analysis (TGA). The physical, structural, and surface properties of the microporous carbons were characterized with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscope (FESEM), elemental analysis, and physical adsorption of nitrogen. Microporous carbons with high surface areas, pore volumes and nitrogen-containing surface functional groups can be readily synthesized. 相似文献
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Three inorganic adsorbents were applied as templates to produce porous carbons from polystyrene-based organic polymers. As matrices, amorphous silica gel, mesoporous alumina and microporous zeolite 13X were used. Organic precursors were polystyrene sulfonic acid (co-maleic acid) sodium salt and polystyrene co-maleic acid isobutyl/methyl mixed ester. The impregnated templates were carbonized at 800 °C. After removal of inorganic matrices porous carbons were obtained. Materials were characterized by adsorption of nitrogen, thermal analysis, potentiometric titration and SEM. Owing to the template carbonization, highly mesoporous carbons were obtained (SBET up to 1500 m2/g, Vt up to 3 cm3/g) with majority of pores with sizes between 20–200 Å. Although the carbons were not replicas of their matrices, the carbonization within the confined space with utilization of self-released pore formers resulted in unique carbonaceous materials with very acidic surface. That acidity is linked to either exothermic effect of sodium reactivity with moist air or susceptibility for air oxidation of small graphene layers formed in the confined pore space. 相似文献
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Nannan Wang Yong Hong Terence Xiaoteng Liu Qi Wang Jiarui Huang 《Ceramics International》2021,47(1):899-906
A microporous–mesoporous carbon has been successfully prepared via carbonization of sucrose followed by heat treatment process. The obtained porous carbon possesses abundant micropores and mesopores, which can effectively increase the sulfur loading. The composite exhibited a remarkable initial capacity of 1185 mAh g?1 at 0.2 A g?1 and maintained at 488 mAh g?1 after 200 cycles, when employed for lithium?sulfur batteries. Moreover, the composite displayed enhanced rate capabilities of 1124, 914 and 572 mAh g?1 at 0.2, 0.5 and 1.0 A g?1. The outstanding electrochemical capabilities and facile low?cost preparation make the new microporous–mesoporous carbon as an excellent candidate for lithium sulfur batteries. 相似文献
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Norikazu Nishiyama Tao Zheng Yusuke Yamane Yasuyuki Egashira Korekazu Ueyama 《Carbon》2005,43(2):269-274
Microporous carbons have been synthesized by the carbonization of cationic surfactant-resorcinol/formaldehyde (RF) composites, which were themselves formed by electrostatic organic-organic interaction. The porous structure produced by the decomposition of the surfactant plays an important role for the gasification of the RF polymer at higher temperatures. The pore size of the carbon prepared from tetrapropylammonium bromide (TPAB)-RF, cetyltrimethylammonium bromide (C16TAB)-RF and decyltrimethylammonium bromide (C10TAB)-RF mixtures can be estimated as 0.53 nm from the Horvath-Kawazoe method using N2 adsorption isotherms. Their pore size distributions were very narrow, showing that the microporous carbons derived from surfactant-RF mixture may have promise as adsorbents and membrane materials. 相似文献
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Marta Sevilla 《Carbon》2006,44(3):468-474
Graphitic porous carbons with a wide variety of textural properties were obtained by using a silica xerogel as template and a phenolic resin as carbon precursor. The synthetic procedure used to prepare them was as follows: (a) infiltration of the porosity of silica by a solution containing phenolic resin, (b) carbonization of the silica-resin composite, (c) removal of the silica skeleton, (d) impregnation of the templated porous carbon with a metallic salt and (e) catalytic graphitization of the impregnated carbon by heat treatment at 900 °C. The graphitization of the carbons thus prepared varies as a function of the carbonization temperature used and the type of metal employed as catalyst (Fe, Ni or Mn). The porous characteristics of these materials change greatly with the temperatures used during the carbonization step. These graphitized carbons exhibit high electrical conductivities up to two orders larger than those obtained for the non-graphitized samples. 相似文献
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《Fuel Processing Technology》1998,57(3):149-161
Active carbons with a burn-off of 52% have been prepared from four coals of different rank and origin after preoxidation to different degrees at 543 and 473 K, and further carbonization at 1123 K. The activation has been carried out with CO2 at 1123 K at two flow rates viz. 7 cm3 min−1 and 500 cm3 min−1. Active carbons have also been prepared from a preoxidized coal by activation to different degrees of burn-off between 10 and 80%. The effect of the degree of oxidation, the flow rate of the activating gas and the extent of burn-off on the porous structure development of active carbons has been examined. The active carbons prepared from unoxidized coal have poor textural characteristics (porosity, N2 and CO2 surface area). Nevertheless, the textural characteristics are enhanced as the degree of preoxidation of the coal is increased. The low flow rate of CO2 (activating gas) produces active carbons with a better microporous character. The degree of activation (the extent of burn-off) of the carbon determines the porous structure of the active carbon. At low degrees of burn-off (less than 50%) the product is largely microporous. At higher degrees of burn-off between 35–65% the product has a mixed porous structure and contains all types of pores. Active carbons with a given textural character can be obtained by controlling the degree of oxidation of coal and the degree of activation of the carbonized material. 相似文献