Synthesis of mesoporous carbon as electrode material for supercapacitor by modified template method

The pore structures and electrochemical performances of mesoporous carbons prepared by silica sol template method as electrode material for supercapacitor were investigated. The mean pore size and mass specific capacitance of the mesoporous carbons increase with the increase of mass ratio of silica sol to carbon source （glucose）. A modified template method, combining silica sol template method and ZnCl2 chemical activation method, was proposed to improve the mass specific capacitance of the mesoporous carbon with an improved BET surface area. The correlation of rate capability and pore structure was studied by constant current discharge and electrochemical impedance spectroscopy. A commercially available microporous carbon was used for comparison. The result shows that mesoporous carbon with a larger pore size displays a higher rate capability. Mesoporous carbon synthesized by modified template method has both high mass specific capacitance and good rate capability.     

Structrue and Characteristics of Mesoporous Silica Synthesized in Acid Medium and Its Reaction Mechanism

1　IntroductionNanoporousmaterialsnotonlypossessasupermicrosizeeffectofnanoparticlesandahighsurfaceactivity ,butalsohaveahugeporevolumeandaloadingcapacity .Sotheyshowanexcellentpotentialforapplicationsinbio logicaltechnology ,medicalengineering ,andnovelf…     

Low-cost preparation of mesoporous silica with high pore volume

Mesoporous silica materials with high pore volume were successfully prepared by the chemical precipitation method, with water glass and a biodegradable nonionic surfactant polyethylene glycol （PEG）. The obtained materials were characterized by transmission electron microscopy （TEM）, scanning electron microscopy （SEM）, thermo gravimetric analyzer and differential scanning calorimetry （TG-DSC）, nitrogen adsorption-desorption measurements, and X-ray diffraction （XRD）. The results showed that the changes of the pore parameters depended on both the surfactant content and heat treatment temperature. When the content of PEG was 10wt% and the obtained PEG/SiO2 composite was heated at 600℃, the mesoporous silica with a pore volume of 2.2 cma/g, a BET specific surface area of 361.55 m^2/g, and a diameter of 2-4 μm could be obtained. The obtained mesoporous silica materials have potential applications in the fields of paint and plastic, as thickening, reinforcing, and flatting agents.     

Structrue and Characteristics of Mesoporous Silica Synthesized in Acid Medium and Its Reaction Mechanism

Structrue and pore characteristics of the mesoporous silica synthesized in acid medium were studied by means of XRD, HRTEM, BET, FT-IR, DSC-TGA, and the reaction mechanism was also investigated deeply. The results show that mesopores in the sample possess hexagonal arrays obviously, whereas the structure of silica matrix is amorphous. The results also show that the acting mode of silica and CTMA^ inside the mesopores was chemical bonding force. The structure of rnesoporous silica was mainly dependent on the aggregational condition of micelle of CTMA^ as well as their liquid- crystallized status. In addition, condensation and dehydration of silicate radicals were accompanied in the process of calcination, which resulted in the mesoporous structure ordered in local range and the pore sizes largening.     

Synthesis and characterization of bimodal mesoporous silica

Mesoporous silica with controllable bimodal pore size distribution was synthesized with cetyltrimethylammonium bromide (CTAB) as chemical template for small mesopores and silica gel as physical template for large mesopores. The structure of synthesized samples were characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and N₂ adsorption-desorption measurements. The experimental results show that bimodal mesoporous silica consists of small mesopores of about 3 nm and large mesopores of about 45 nm. The small mesopores which were formed on the external surface and pore walls of the silica gel had similar characters with those of MCM-41, while large mesopores were inherited from parent silica gel material. The pore size distribution of the synthesized silica can be adjusted by changing the relative content of TEOS and silica gel or the feeding sequence of silica gel and NH₄OH.     

介孔氧化铟纳米粒子的制备及其气敏性质

以介孔氧化硅KIT-6为硬模板制备了介孔氧化铟纳米粒子,并对其进行了X射线粉末衍射（XRD）、扫描电镜（SEM）、透射电镜（TEM）、氮气物理吸附分析。介孔氧化铟纳米粒子具有高的结晶度和有序介观结构,其尺寸为100 nm左右,比表面积为82 m2/g,孔径为4.5 nm左右,孔体积为0.42cm3/g。气敏性能测试结果表明介孔氧化铟纳米粒子对乙醇具有较好的敏感度,优于体相的氧化铟颗粒,在乙醇气体检测方面有潜在的应用。     

Different Synthesis Methods for Ordered Mesoporous Silicas And Their Characteristics Comparison

1　IntroductionInorganicmesoporousmaterialshaveahighpotentialforapplicationsinthefieldsofcatalysis,adsorption ,sepa rationprocesses,biologymaterials,novelopticalmaterialsetc.Mesoporousmaterialshaverapidlyattractedresearchinterestsinthefieldofphysics,chemistryandmaterialssince 1 990s.Oneofthemostrepresentativemesoporousmaterialsismesoporoussilicapreparedbyusingalkylquaternaryammoniumcationicsurfactantsastemplate[1 3 ].Recently ,themesoporoussilicahasbecomeoneofthemostactivefieldsofhost guestass…     

Effects of Assistant Agent on Mesoporous Structure of Silica MCM-41 Molecular Sieves

The nanostrutured mesoporous silica materials MCM- 41 with different pore sizes were synthesized by adding 1,3,5-trimethylbenzene (TMB) as assistant agent in the reactant mixture. The obtained samples were investigated by XRD, HRTEM, FTIR and N2 adsorptions. It is shown that the pore sizes, ordered degree and specific surface area increase effectively with the incremented addition of TMB in an appropriate range, but the (100) peak intensity of XRD pattern becomes weakened and the ordered degree decreases when the additive quantity continued to increase. With the addition of TMB in an appropriate range, the effective surfactant ion pair packing parameter, g=V/ao l, is mediated in the range of 1/3- 1/2 with the increment of V and l, indicating that mesoporons silica is a well-ordered hexagonal structure. Howvever, when the addition of TMB increases, g value becomes larger, which leads to a less long-range ordered structure for the uneven condissolution of TMB.     

有序介孔碳的制备及吸附Cr（Ⅵ）性能比较

利用模板炭化法,以不同温度下合成的SBA-15为模板,制备3种具有不同孔径大小的介孔碳．研究并比较3种不同孔径的介孔碳材料对铬Cr（Ⅵ）的吸附能力．结果表明,介孔碳的投入量、pH值、振荡时间因素等均对铬Cr（Ⅵ）的吸附效果存在一定影响．研究显示：在3个介孔碳中,CMK-3-150对铬的吸附能力最大,可以达到99．2％;当pH=2．0—4．0时,介孔碳对Cr（Ⅵ）的吸附最有利,3个介孔碳吸附能力都超过90％;吸附量随着振荡时间的延长而增加．同时对介孔碳CMK-3-100与传统商用活性碳CAC对Cr（Ⅵ）的吸附性能进行比较,结果表明：与CAC相比,CMK-3吸附量大,吸附速率快,到达平衡时间短,是一种较优的吸附剂．     

A comparative study of drying techniques on the morphology of porous silica gels synthesized via sol-gel process

The effect of drying techniques on the microstructure,morphology and pore structure of porous silica gels was studied in the paper.The gels were prepared by using sol-gel process and different drying routes:freeze-drying (FD),low pressure drying (LPD),high temperature drying (HTD) and chemical modification & ambient drying (CMD) techniques.Observation under pore distribution and structural properties showed that CMD technique leads to homogenous mesoporous silica material with specific surface area of 745 m2/g,and the average pore size around 20 nm,while LPD and HTD result in loosely packed particles with non-isotropic aggregation pattern.The specific surface areas of LPD and HTD samples are 419 and 513 m2/g respectively,and the pore size distribution of the samples are observed distributing widely in range of 10-100 nm.Freeze drying method is a new but prospective way to prepare mesoporous silica.The specific area of FD sample is around 500 m2/g.By the comparison for the properties of the gels,this paper wants to induce a further interest in finding a proper method to synthesize the porous silica gels for low price use.     

模板剂结构和合成温度对两步法制备介孔硅结构的影响

以F108和F127为模板剂,在不添加无机盐或辅助剂情况下,采用两步法在弱酸性体系中分别制备了具有Im3m结构的SBA．16及Fm3m结构的FDU-12硅基介孔材料．采用X射线衍射（XRD）、透射电子显微镜（TEM）及氮气吸附-脱附对其进行了表征,结果显示：在此条件下制备的两种不同结构的立方介孔硅均为典型的小孔（3．57～4．26nm）厚壁（9．68～9．81nm）型硅基介孔材料．结合制备过程中反应物组成及合成温度对形成小孔厚壁型介孔材料的过程进行了讨论．对体系合成温度变化的研究表明：温度的微小变化对最终产物有序性有着很大的影响,而最终产物的结构则是由所用的模板剂结构决定的．     

以非离子模板剂两步法合成介孔二氧化硅

以聚乙氧烯(20)失水山梨醇酯为结构模板剂,在高于硅的等电点条件下(pH为2～5),采用预水解两步法,合成了介孔氧化硅材料.分析了介孔氧化硅材料的合成过程,认为酸度、无机盐等因素对介孔二氧化硅有重要影响.     

Simple synthesis of magnetic mesoporous carbons with high surface areas by soft-template method

Magnetic Fe-containing ordered mesoporous carbons (Fe/OMCs) with high surface areas and pore volume were synthesized through a simple soft-template route, wherein phenolic resin was used as a carbon precursor, triblock copolymer F127 as a template agent, tetraethyl orthosilicate (TEOS) as a silica precursor and hydrated iron nitrate as an iron source. The effects of carbonization temperature, loading degree of TEOS on the structural parameters of these Fe/OMCs were evaluated by X-ray diffraction (XRD) and N₂ sorption analysis. The ordering, the specific surface area and the total pore volumes increased with the increase of carbonization temperature from 600 to 850 °C. And the specific surface area and the total pore volumes increased with the increase of TEOS loading.     

APTES改性介孔二氧化硅的制备及其 对重金属离子的吸附

以介孔二氧化硅为载体,3-氨基丙基三乙氧基硅烷(APTES)为改性剂,成功制备了氨基硅烷改性介孔硅球.并利用透射电子显微镜、能量色散X射线光谱仪和傅里叶变换红外光谱仪等对制备的介孔硅球进行了表征,同时考察了改性后的介孔硅对重金属铅的吸附效应.结果表明:通过改性处理,3-氨基丙基三乙氧基硅烷被成功接枝到介孔硅表面;氨基功能化介孔硅溶胶吸附剂对重金属Pb2+具有选择吸附特性,且吸附量随反应原料中APTES含量的提高呈现出相应的增加趋势.     

三模板剂法合成钛硅介孔纳米球

以十二烷基硫酸钠（DDS）、十六烷基三甲基溴化铵（CTAB）、聚丙烯-聚乙烯-聚丙烯三嵌段共聚物（P123）为模板剂,以硫酸钛和偏硅酸钠为金属源,使用三模板剂法首次合成出钛硅介孔纳米球材料。用XRD,ICP,HRTEM,SEM,FTIR和低温氮吸附等多种手段对材料进行了袁征。结果表明,所制备的钛-硅材料是介孔纳米球结构,球径约为2000nm。当n（钛）／n（硅）增加时,介孔孔径增大,比表面积降低。     

介孔氧化硅材料的合成及应用研究

采用十六烷基三甲基溴化铵（CTAB）为模板剂，通过加入不同量的1，3，5－三甲基苯（TMB）作为增大孔径的辅助剂合成出了不同孔径大小的氧化硅粉末，XRD、N2吸附曲线等测试手段表明所合成的材料为具有MCM－41结构特征的介孔材料；以该种材料制备了超微孔领域的多孔陶瓷，同时探讨了辅助剂对材料介孔结构和陶瓷气孔率的影响。结果表明，当辅助剂摩尔比小于x=0.4时，随着辅助剂加入量的增加，介孔材料的孔径、比表面积、结晶有序度等相应增加，但当加入量超过此范围时，结晶有序度反而下降，所获得的超微孔陶瓷其最大显气孔率可达56％。     

介孔碳片的合成及吸附脱硫性能

采用溶胶-凝胶法,以三嵌段共聚物聚氧化乙烯氧化丙烯氧化乙烯EO27- PO61-EO27 (P104)为模板剂,蔗糖为共模板,正硅酸乙酯(TEOS)为硅源,在强酸性及无机盐存在条件下制备出介孔硅片,并以此为硬模板,通过浓硫酸处理的方法成功制备了介孔碳片.并采用扫描电子显微镜、N2吸附-脱附实验对合成的介孔碳片进行了表征...     

酸性条件下介孔二氧化硅材料的制备

非离子表面活性剂为结构模板剂,在高于硅的等电点条件下（pH=2—5）,采用预水解法,合成了介孔氧化硅材料．分析了介孔氧化硅材料的合成过程,认为酸度、反应温度等因素对合成出的介孔材料具有重要作用．     

SBA－16硅基介孔材料结构对Cd^2＋吸附性能的影响

分别采用一步法和两步法,在不同酸性介质中设计合成了Im3m结构的SBA－16硅基介孔材料,并通过XRD、TEM、氮气吸附－脱附、^29Si固体核磁等手段进行了表征,研究SBA－16硅基介孔材料合成条件和结构对溶液中Cd^2＋吸附性能的影响．结果表明：在相同条件下,SBA－16硅基介孔材料的孔径越大、比表面积越高、孔壁表面Si—OH的数量越多,对Cd^2＋的吸附性能越佳．     

双孔硅胶整体材料的一步法合成及结构表征

采用溶胶-凝胶（sol-gel）技术,以嵌段共聚物Pluronic F127（EO106P070EO106）为模板剂,经一步法直接合成了具大孔和介孔结构的双孔硅胶整体材料,并通过SAXD、SEM、比表面积及孔径分析等手段对其结构进行了表征,结果表明所合成的硅胶整体材料具有大孔和介孔等级结构,且介孔具有一定程度的有序性。考察了反应条件对硅胶整体材料结构的影响,实现了对硅胶整体材料大孔结构、骨架结构及介孔结构的独立调控。该类型材料的高比表面积和双孔结构尺寸范围特别适用于作为一种新型的色谱分离材料。