酚醛-糠醛基炭气凝胶对NaCl溶液的电吸附行为

以酚醛-糠醛基炭气凝胶为电极,用恒电位仪提供直流电压,在静态电吸附装置进行了NaCl溶液电吸附试验。考察了NaCl溶液浓度、炭气凝胶电极厚度及施加的电位等因素对电吸附的影响。研究表明,随着NaCl溶液浓度的增加,电吸附量明显增加。在低浓度下,微孔的“电场交叠效应”非常显著。0.6V~2.0V范围的电吸附试验表明,电位在1.5V以下电吸附量随电位改变异常显著,1.5V以后变化趋缓。炭气凝胶电极厚度在0.5nm~1.5mm范围增加时,电吸附量呈现单调减少的趋势。在电压为1.2V厚度为0.5mm时,其电吸附量达到12.7mg/gCA。理想的电吸附电极应富含中孔并尽可能降低电极厚度。     

酚醛环氧-环硫树脂的合成和表征

采用F-51环氧树脂与硫化剂在水溶液中反应制备F-51环氧-环硫树脂。聚合物用红外光谱,核磁共振进行了表征。研究了反应时间,反应温度,环硫树脂含量对凝胶时间的影响。实验结果表明,随着环硫树脂的量的增加,凝胶化时间逐渐缩短。同时,还对环氧-环硫树脂的折光指数进行了测试。     

木质素酚醛基炭气凝胶的制备及电化学性能

以木质素、苯酚和甲醛为原料,NaOH为催化剂,溶胶凝胶法制备了木质素酚醛基有机凝胶,经CO2超临界干燥及高温炭化得到了炭气凝胶(LPCA)。采用扫描电镜(SEM)、比表面及孔结构分析仪表征了材料的结构,通过恒流充放电测试了炭材料的电化学性能。结果表明,制备得到的炭气凝胶以微孔和中孔为主,比表面积达356.6m2/g,首次放电比容量为583.94mAh/g,充放电循环30次比容量未见明显的衰减。     

炭气凝胶微球的凝胶化机理

以间苯二酚和甲醛为原料,溴化十六烷三甲基铵为催化剂,通过反相悬浮聚合法成功制备了炭气凝胶微球.研究了反应体系的黏度、酸度、温度以及反应中间产物紫外光谱的变化情况,探讨该凝胶反应的作用机理.结果表明:凝胶反应是一个酚醛缩合过程,其反应历程可以分为线性缩聚、交联、胶粒生长和宏观凝胶化四个阶段.     

苯酚-间甲酚-糠醛基炭气凝胶的制备及微结构控制

以苯酚、间甲酚和糠醛为原料,在正丙醇溶剂中以盐酸为催化剂经溶胶-凝胶过程合成了醇凝胶,直接超临界正丙醇干燥得到有机气凝胶,在氮气保护下裂解制备出富含中孔的炭气凝胶.用IR、N2吸附、SEM、TEM等表征气凝胶的结构特征,考察了问甲酚苯酚摩尔比对凝胶结构的影响.结果发现:提高间甲酚的含量能够增强聚合物的交联密度,减小聚合物与溶剂的相溶性,缩短相分离时间,有利于得到较小的纳米颗粒和孔径的炭气凝胶.所制得的炭气凝胶平均中孔孔径随间甲酚含量的增加从47 nm逐渐减小至13 nm,BET比表面积和中孔孔容在m-C/P=0.33时达到最大值.     

单宁改性酚醛基炭气凝胶的制备及其CO2吸附性能

基于绿色低成本的单宁所具有的大量反应性羟基,其与醛类反应具有与苯酚或间苯二酚相似的机制。在传统的酚醛树脂基(苯酚-尿素-甲醛)炭气凝胶的基础上,通过添加单宁进行改性,成功制备出新型高效的CO₂吸附用酚醛基炭气凝胶。通过扫描电子显微镜(SEM)、傅里叶红外光谱(FTIR)和氮气吸脱附测试对其表面化学和孔隙结构进行了系统表征,同时通过CO₂吸脱附测试对其CO₂吸附量、选择性吸附及吸附热等进行了研究。结果表明：以绿色可再生的生物质原料单宁对原料进行部分取代,不仅可以显著降低产品成本,还可以明显改善其CO₂的吸附性能。当单宁的添加量(15 g)为苯酚用量的50wt%时,样品具有最大的比表面积(1 376.31 m2·g^-1)和微孔体积(0.55 cm3·g^-1),是一种极具潜力的气体吸附材料。其相应的CO₂吸附量高达5.36 mmol·g^-1,选择性吸附和吸附热则分别为16.84和34.49 kJ·mol^-1<...     

炭气凝胶负载Pt基催化剂的制备及其甲醇氧化催化性能

以间苯二酚(R)和甲醛(F)为原料,制备R-F炭气凝胶(RF-CAs).继以后者为载体采用浸渍还原法制备铂基催化剂Pt/CA,并比较其与由相同负载工艺制得的以Vulcan XC-72为载体的铂基催化剂Pt/XC72的催化甲醇氧化反应的性能.结果表明,前者具明显高的甲醇氧化催化活性,显示CAs是一种极具潜在竞争力的燃料电池催化剂载体材料.     

辐射合成水凝胶的结构表征

本文用ＩＲ、ＵＶ光谱、光射线衍射仪及ＤＴＡ与ＴＧ等分析手段，对辐射合成水凝胶进行了结构表征，并探讨了这些结构因素对水凝胶溶胀性能的影响。     

炭气凝胶结构的形成和控制

炭气凝胶是一种新型的多孔炭材料,具有可调控的独特的孔结构和良好的导电性,可应用于超级电容器、高效吸附材料、催化剂载体等.本文研究了酚醛基炭气凝胶纳米结构的形成过程和控制方法.炭气凝胶的孔结构主要取决于其前驱体--有机气凝胶.有机气凝胶结构源于溶胶-凝胶聚合中的微相分离过程,相分离经历了从成核--生长--亚稳分解的过渡,在成核--生长区停留时间的长短决定了气凝胶的骨架结构和孔结构.微相分离过程受到酚醛团簇的化学结构和溶剂环境的影响,通过调控酚醛团簇的化学结构和溶胶-凝胶聚合的溶剂环境,可以实现有机气凝胶的纳米结构调控,结合干燥和炭化控制,可以实现炭气凝胶结构的有效调控.     

炭气凝胶及其有机气凝胶前驱体的吸附性能

间苯二酚和糠醛的醇溶液在六次甲基四胺催化下经溶胶-凝胶过程合成醇凝胶,常压干燥后得到有机气凝胶,经炭化获得炭气凝胶.利用TEM和N2吸附表征了炭气凝胶及其有机气凝胶前驱体的结构,并通过有机蒸汽吸附实验研究了气凝胶的结构-吸附性能关系.实验结果表明：有机气凝胶和炭气凝胶对极性有机蒸汽的静态饱和吸附量高于对非极性有机蒸汽的静态饱和吸附量;提高热处理温度,有利于气凝胶对低浓度极性有机蒸汽和各种浓度非极性有机蒸汽的吸附,但不利于对高浓度极性有机蒸汽的吸附;随着有机蒸汽浓度的提高,气凝胶对极性有机蒸汽的吸附量明显增大,但对非极性有机蒸汽的吸附量影响不大,仅略微上升.此外,气凝胶的室温脱附率高达60 %～85 %.     

新型纳米甲酚-甲醛气凝胶的制备及表征

首次以混甲酚（J）和甲醛（F）为原料,在NaOH(C)催化作用下制备混甲酚甲酸气凝（JF）,考察了制备条件与气凝胶性能的关系,并用TG,TEM,NMR,FT－IR,N2吸附表征了气凝胶结构,结果表明,JF气凝胶的密度随反应物浓度和催化剂含量的增加而增加,混;甲酚与甲酝酿落空－凝胶过程中形成的交联键是亚甲基醚键和亚甲基键,JF气凝胶是可孔约30nm,网络粒子直径约20nm,是典型的中孔材料,有机气凝热解可以得到炭气凝胶,在300－600度之间,JF气凝胶失重显著。     

Enhanced field emission characteristics of nitrogen-doped carbon nanotube films grown by microwave plasma enhanced chemical vapor deposition process

Nitrogen-doped carbon nanotube (CNT) films have been synthesized by simple microwave plasma enhanced chemical vapor deposition technique. The morphology and structures were investigated by scanning electron microscopy and high resolution transmission electron microscopy. Morphology of the films was found to be greatly affected by the nature of the substrates. Vertically aligned CNTs were observed on mirror polished Si substrates. On the other hand, randomly oriented flower like morphology of CNTs was found on mechanically polished ones. All the CNTs were found to have bamboo structure with very sharp tips. These films showed very good field emission characteristics with threshold field in the range of 2.65-3.55 V/μm. CNT film with flower like morphology showed lower threshold field as compared to vertically aligned structures. Open graphite edges on the side surface of the bamboo-shaped CNT are suggested to enhance the field emission characteristics which may act as additional emission sites.     

丙烯酸系三元嵌段共聚物的合成与表征

利用基团转移聚合（ＧＴＰ）技术,在室温下使用单官能团引发剂,通过对单体加料顺序与时机的控制,合成了一系不同组成比,不同分子量的聚甲基丙烯酸甲酯－聚丙烯酸正丁酯（或乙酯）－聚丙烯腈嵌段共聚物,用ＦＴ－Ｉ,Ｈ－ＮＭＲ,ＧＰＣ等方法对共聚物进行表征,共聚过程活性中心的转移机理。     

Synthesis and Characterization of Transition Metals Doped ZnO Nanorods

Different morphologies of undoped and transition metals(Mn,Co and Ni) doped one-dimensional(1D) ZnO nanocrystals were successfully synthesized by chemical method in an air atmosphere using polyvinylpyrrolidone(PVP) as a surfactant.The structure and optical properties were studied by scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD),thermal gravimetric analysis(TGA),ultraviolet visible(UV-vis) absorption spectra and photoluminescence(PL) spectra.The doped ZnO nanorods exhibited a blue-shifted band gap and enhanced ultraviolet(UV) emission.In addition defect related emission was observed for the doped ZnO.     

SrZrO3基质氧化物粉体的水热合成和表征

用水热晶化法制备了ＳｒＺｒＯ３纯相和ＳｒＺｒ１－ｘＭｘＯ３－α（Ｍ＝Ａｌ、Ｇａ、Ｉｎ；ｘ≤０．２０）体系氧化物，通过ＸＲＤ、ＳＥＭ、ＩＲ＾２７Ａｌ ＭＡＳＮＭＲ和化学分析，对产物的物相、粒度和所掺杂质进入晶格的数量进行了表征。结果表明，产物为正交结构钙钛矿、粒度为５￣１５μｍ，在０≤ｘ≤０．２０范围内，产物的金属离子比与投料基本一致。     

Formation of new carbides with diamond structure from carbon film containing transition metal

New carbide crystallites, which have a solid-solution phase with diamond structure, were formed from amorphous carbon film containing a transition metal such as Fe, Co, Mo or Ti by vacuum heating at 500-800 °C. The lattice constants for each solid-solution phase have been determined from electron diffraction patterns and high-resolution transmission electron microscope images. The formation of carbon polymorphs has been summarized as being dependent on the heat treatment temperature.     

Morphological modification of β-FeSi2 on Si(111) by high temperature growth and post-thermal annealing

β-FeSi₂ crystals have been grown on Si(111) substrates, and morphological modification of the β-FeSi₂/Si(111) by high temperature growth and post-thermal annealing was investigated. The morphological feature of the β-FeSi₂ crystals significantly depends on the growth conditions, especially, substrate temperature during growth. The β-FeSi₂ continuous layers with relatively smooth surfaces were grown at the low substrate temperatures of 650-700 °C with exposure of the grown layers to Sb flux during the growth. On the other hand, nano-scaled islands have been grown at the higher substrate temperature of 850 °C. The structural property, interfacial morphology and growth evolution of the β-FeSi₂ islands were examined, and compared with those for the layers grown at a lower substrate temperature. In addition, the morphological evolution of the β-FeSi₂/Si layers by post-thermal annealing was examined, and it was found that the interfacial smoothness between the β-FeSi₂ layers and the Si(111) substrates was improved by the post-thermal annealing on condition that a thin SiO_x amorphous overlayer should be formed on the β-FeSi₂ layer during the post-thermal annealing. The mechanisms of the morphological modification at the β-FeSi₂/Si(111) interface by the post-thermal annealing will also be discussed.     

Structural property of β-FeSi2 layers deposited on FeSi from a molten salt

The microstructural properties of the β-FeSi₂/FeSi structure prepared from a molten salt have been characterized using transmission electron microscopy (TEM). The β-FeSi₂ films were grown on FeSi substrates at the heat treatment temperature of 900 °C from 1 min to 24 h using the molten salt technique. It is found that the films consisted of a thin surface layer and a thick underlying layer with columnar-shaped domains. The crystallographic directions of the domains are mostly randomly oriented. The β-FeSi₂ domains in the film, however, have specific crystallographic orientation relationships with the adjoining domains and the FeSi substrate. A high density of the stacking faults on the β-FeSi₂ (100) planes was also observed through the films. Moreover, the growth evolution of the β-FeSi₂ domains, the defect characteristics and the formation mechanism of the defects are discussed.     

超临界CO2中聚乳酸的合成及表征

以辛酸亚锡为催化剂用超临界二氧化碳作溶剂成功地实现了L-丙交酯的开环聚合,聚合产物用FT-IR、^1H-NMR、^13C-NMR、DSC和GPC进行了分析表征,结果表明：超临界二氧化碳流体中左旋丙交酯开环聚合不是离子型聚合．可能是配位一插入聚合。所合成的聚乳酸具有很高的光学活性;所得聚合物无论分子量大小,都具有熔点和中等结晶度,且随分子量的增大而升高。