Morphological characterization of microporous carbon materials

Abstracts are not published in this journal     

Morphological characterization of microporous carbon materials

Abstracts are not published in this journal This revised version was published online in November 2006 with corrections to the Cover Date.     

Boron-doped microporous nano carbon as cathode material for high-performance Li-S batteries

In this study,a boron-doped microporous carbon (BMC)/sulfur nanocomposite is synthesized and applied as a novel cathode material for advanced Li-S batteries.The cell with this cathode exhibits an ultrahigh cycling stability and rate capability.After activation,a capacity of 749.5 mAh/g was obtained on the 54th cycle at a discharge current of 3.2 A/g.After 500 cycles,capacity of 561.8 mAh/g remained (74.96％ retention),with only a very small average capacity decay of 0.056％.The excellent reversibility and stability of the novel sulfur cathode can be attributed to the ability of the boron-doped microporous carbon host to both physically confine polysulfides and chemically bind these species on the host surface.Theoretical calculations confirm that boron-doped carbon is capable of significantly stronger interactions with the polysulfide species than undoped carbon,most likely as a result of the lower electronegativity of boron.We believe that this doping strategy can be extended to other metal-air batteries and fuel cells,and that it has promising potential for many different applications.     

An activated microporous carbon prepared from phenol-melamine-formaldehyde resin for lithium ion battery anode

Microporous carbon anode materials were prepared from phenol-melamine-formaldehyde resin by ZnCl₂ and KOH activation. The physicochemical properties of the obtained carbon materials were characterized by scanning electron microscope, X-ray diffraction, Brunauer–Emmett–Teller, and elemental analysis. The electrochemical properties of the microporous carbon as anode materials in lithium ion secondary batteries were evaluated. At a current density of 100 mA g^?1, the carbon without activation shows a first discharge capacity of 515 mAh g^?1. After activation, the capacity improved obviously. The first discharge capacity of the carbon prepared by ZnCl₂ and KOH activation was 1010 and 2085 mAh g^?1, respectively. The reversible capacity of the carbon prepared by KOH activation was still as high as 717 mAh g^?1 after 20 cycles, which was much better than that activated by ZnCl₂. These results demonstrated that it may be a promising candidate as an anode material for lithium ion secondary batteries.     

用于空气中水蒸气吸-脱附的微孔泡沫炭制备研究

以蜜胺泡沫体为模板,采用氟化聚酰业胺制备了微孔泡沫炭.测定了其对环境中水气的吸附/脱附行为,发现:泡沫炭在空气中400℃活化1 h,可以提高其对水气的吸附能力.与活化前相比,对水气的吸附量几乎高达3倍,尽管其微孔容积仅增大了1.5倍.对环境水气中的可逆吸附率与微孔容积成线性关系,微孔容积为0.75mL/g的泡沫炭,其水气吸附率约为质最分数40%.     

TiO2在微孔型活性炭纤维上的固载及其对苯酚的光催化降解

以环氧树脂作为TiO2与活性炭纤维(ACF)之间联结的前驱体，使TiO2粘附于纤维表面。后经氮气氛下400℃-580℃不同温度的煅烧处理，制得TiO2／ACF复合体。采用BET，SEM，XRD及UV—Vis光谱等手段对复合体的物理化学特性进行了表征。以水中苯酚为目标污染物考察了TiO2／ACF样品的光催化性能、结果表明，460℃煅烧品较其他样品对苯酚具有更好的去除能力。在其重复利用过程中，始终保持了高的光催化效率，直至第三次循环，其最终对苯酚的去除量仍与P25粉体相当。而且，牢固负载的TiO2更具实用性，易于从水中回收。     

A microporous aluminum-based metal-organic framework for high methane,hydrogen, and carbon dioxide storage

We report a microporous aluminum-based metal-organic framework(MOF),BUT-22 for high methane(CH₄),hydrogen(H₂),and carbon dioxide(CO2)storage.At 296 K and 80 bar,BUT-22 exhibits a high gravimetric CH4 storage capacity of 530 cm³(STP)/g(0.379 g/g).BUT-22 also has a high gravimetric H₂storage capacity of 12 wt.%at 100 bar and 77 K.In addition,the CO₂adsorption studies revealed that BUT-22 exhibits a high absolute gravimetric CO2 uptake of 1.7 g/g at 296 K and 40 bar.     

Novel microporous carbon material with flower like structure templated by MCM-22

Novel flower like microporous carbons with very high surface area have been synthesized for the first time using MCM-22 zeolite as a template and sucrose as a carbon source. The textural parameters of the materials can easily be tuned by the simple adjustment of the sucrose to MCM-22 weight ratio. It has been also found that the specific surface area of the microporous carbon materials is much higher as compared with that of its parent zeolite template.     

炭黑增强橡胶复合材料的大变形细观力学模型

为考察炭黑对橡胶复合材料超弹性力学行为的影响,首先,利用不同填充体积分数的炭黑增强橡胶复合材料的准静态力学试验数据,对现有的基于均质化方法的"变形放大"细观力学模型的大变形表征能力进行了评估。其次,在此基础上提出了新的"第一不变量放大"关系,并获得了较为合理的预测结果。最后,利用随机序列吸附算法建立了较接近材料真实细观结构的球形颗粒填充数值模型,进行了大变形情况下的三维数值模拟;为考察颗粒聚集效应的影响,还设置了颗粒均匀随机分布和团聚随机分布两种形式。计算结果与试验数据的对照表明:提出的三维细观数值模型已经能在一定程度上预测填充橡胶的大变形宏观力学行为,且颗粒团聚随机分布模型的预测能力更好一些。试验结果验证了该模型的合理性,所建模型为进一步的相关研究提供了参考。     

KOH活化法制备汉麻秆活性炭及其微孔结构的研究

采用生物质材料制备比表面积大、微孔结构发达的活性炭,对于缓解资源紧缺、拓展活性炭在气相吸附和双电层电容器等方面的应用具有重大意义。以汉麻秆为原料、KOH为活化剂制备活性炭,通过正交试验探讨碱炭比、活化温度、活化时间对活性炭得率和碘吸附值的影响;采用场电镜、孔径分析仪对样品的微孔结构进行分析。结果表明,影响活性炭得率和碘吸附值的最显著因素分别为碱炭比和活化温度,在碱炭比4∶1、活化温度900℃、活化时间为0.5h的条件下,活性炭得率为72%、碘吸附值为2 047mg/g,比表面积为1 924.08m2/g,总孔容为1.01cm3/g,平均孔径为2.1nm;该活性炭的微孔结构发达(微孔率为81.19%),孔径分布较窄,同时存在超微孔和极微孔,且极微孔含量很高。     

PP微孔薄膜

聚丙烯微孔薄膜的性能,具有孔隙率30—35%,平均孔径在200—800A,有效氮气透过率1—5×10-3ml/cm2每秒(在自然环境),它的拉伸强度在所有方向上都大于60Mpa,比较了通过双向拉伸高β晶含量和经过热定型微孔薄膜的性能。     

Evidences of Rubber Grafting on Activated Carbon Surfaces Containing Fullerene-like Structures

It is shown that graphite is converted into an high disordered carbon black by prolonged ball milling. The kinetics of this transformation has been followed by powder x-ray diffraction, measurements of the crystallinity and of the surface area. Ball milling is able to introduce an high concentration of defective sites in the pristine graphite including the fullerene-like structures. By mixing with natural rubber both the pristine and the ball-milled graphite, it is shown by bound rubber measurements that the amount of rubber grafted (chemically linked) on the pristine graphite surface is negligible but reaches a very high level in the ball-milled graphite. Similarly, ball-milling of N660 carbon black causes a deep activation of its surface activity which can be measured by a significant increase in the bound rubber level and in the amount of grafted rubber in comparison to the pristine N660 sample. The bound rubber measurement has been performed also on a natural rubber masterbatch with extracted fullerene carbon black (EFCB). Also in this case extremely high levels of rubber grafting have been achieved in comparison to graphite. It is discussed and demonstrated that the fullerene-like nanostructures in carbon blacks play a key role in the formation of bound rubber phenomenon and in grafting natural rubber on carbon black surface.     

富勒烯和纳米管结构二硫化钨的研究进展

简要介绍了无机富勒烯结构二硫化钨(IF-WS2)纳米粒子和纳米管的发现和结构特点,详细介绍了IF-WS2纳米粒子和纳米管的化学气相反应、直接加热、模板法、化学气相输运等制备方法,阐述了它们的包裹形成机理、摩擦性质和在AFM针尖方面的潜在应用,旨在指出它们具有重要的科学研究价值和潜在的应用价值.     

低摩擦长寿命类富勒烯碳基薄膜的制备及其摩擦学特性

以甲烷(CH4)为前躯体,利用等离子体增强化学气相沉积(PECVD)技术,在单晶硅〈n-100〉基底表面制备含氢类富勒烯碳基薄膜(FL-C∶H)。采用高分辨透射电镜(HRTEM)、拉曼光谱仪(LABRAM)和多功能X射线光电子能谱仪(XPS)对薄膜及磨屑结构进行表征;利用摩擦磨损试验机、扫描电子显微镜(SEM)分别测试薄膜的摩擦学性能和观察磨屑的微观形貌。结果表明,所制备的碳基薄膜具有类富勒烯纳米结构,且磨屑的显微结构亦呈现类富勒烯结构的特征。同时,类富勒烯纳米结构的碳基薄膜具有优异的摩擦学性能,与传统非晶类金刚石薄膜相比,其磨损寿命显著提高,在载荷为30N、摩擦速率为0.1m/s下薄膜的磨损寿命为3 538.2m,摩擦系数低至0.012左右,显示出长寿命低摩擦特性。