纳米金刚石球晶的激光溅射产生与透射电镜表征

在高温高压合成金刚石技术日趋成熟的同时，气相沉积（CVD）条件下实现常压金刚石膜的合成已倍受人们的关注．利用脉冲激光溅射石墨，发现可在一定的基底上获得一类具有某些金刚石特征的薄膜，即类金刚石碳膜（DLC）［‘－‘j．这为在常规条件下合成金刚石带来了新的希望．但DLC只具有金刚石的某些特征，而基本上不具备晶体的有序结构［”’j．我们曾报道了在激光液相溅射的产物中观察到众多的碳球D‘，并通过高分辨透射电镜（HREM）、选区衍射（SAED）及其它相关实验，确定了其具有金刚石结构．且实验部分实验所用的激光是Q开关Nd…     

原子层沉积技术制备高性能低铂载量燃料电池膜电极

应用原子层沉积技术在碳材料复合电极基体上制备了低铂载量的高性能膜电极.将碳载体(XC-72R)与聚四氟乙烯乳液均匀混合后涂布在碳纸上,在马弗炉中350℃烧结,构成复合电极的基底.然后采用原子层沉积技术将铂活性组分沉积在电极基底上制得膜电极的阳极,将该阳极与经过预处理的质子交换膜及阴极压合即得膜电极.由扫描电镜(SEM)、透射电镜(TEM)、X射线衍射(XRD)和循环伏安(CV)等分别表征该电极,单电池测试膜电极的性能.结果表明,活性组分在阳极中高度分散,膜电极具有良好的稳定性.膜电极的最大功率密度可达3.34 kW.(gPt)-1,是商业催化剂常规方式下制备的膜电极的1.76倍.以本文方法制得的膜电极具有铂载量低、单位质量铂的能量密度高等特点,有望在燃料电池领域应用.     

用理学3064X荧光仪分析碳

在理学３０６４Ｘ荧光仪上采用十八烷基马来酸（ＯＨＭ）晶体作为色散单元，通过改造电路，调整晶体倾角，获得对碳分析的良好线性，在流气正比计数器（ＦＰＣ）窗膜分别为５μｍ和０．６μｍ条件下，碳元素的峰背比分别达到３８．９１和５４．０４。作者分析了白口铸铁和碳化硅中的碳，结果表明在理学３０６４Ｘ荧光仪上定量分析碳是可行了，具有快速、简便、准确、多元素同时分析的特点，可用于日常分析     

流动注射-示差脉冲阳极溶出伏安法中壁喷玻碳汞膜电极表面状态研究

通过显微观察,研究了在流动注射一示差脉冲阳极溶出伏安法中,使用壁喷玻碳电极时,在不同的预镀汞膜条件下,在电极表面上形成的汞膜的状态。并获得了适宜的预镀汞膜条件。适宜的预镀汞膜条件为:。     

用TEM分析溅射法制备Ag超微粒的空间分布

用透射电镜对在氩气中电离溅射沉积于碳膜上的Ag超微粒进行了直接研究。通过明场象和电子衍射观察分析发现,在溅射入射角为60°时,经不同的出射角收集,形成的超微粒的粒径、粒径分布、形态和物相结构各有不同。     

恒电位条件下制备聚苯胺PAn及其电化学行为

恒电位条件下在玻碳电极上用电化学聚合法制备了聚苯胺膜，研究了聚合条件如聚合电位，聚合介质，苯胺浓度等对聚苯胺膜化学性质的影响，从而确定了制备聚苯胺的最佳聚合方法和条件，并讨论了在不同支持电解质溶液中和不同ＰＨ值条件下ＰＡｎ膜的循环伏安行为，认为５５０ｍＶ出现的氧化还原峰与阴离子的掺杂有关。     

空心碳半球锂离子电池负极的高倍率性能研究

以聚苯乙烯球为模板,通过水热法包裹硬碳层,又用微波法迅速引发聚苯乙烯核裂解的两步反应,制备了高比表面的空心碳半球.采用扫描电镜和透射电镜观察材料形貌,并测试该负极的电化学性能.在高倍率充放电条件下,与石墨、中间相碳微球电极相比,空心碳半球显现出了更高的容量和优异的寿命.     

脉冲电弧放电电离甲醇溶液制备碳膜的研究

利用脉冲电弧放电电离甲醇溶液在常压下研究了含金刚石成分的碳膜的制备。用扫描电子显微镜(SEM)、傅里叶红外光谱(FT-IR)、激光Raman光谱和X射线衍射(XRD)研究了在确定的基片温度下甲醇浓度以及放电电压等沉积条件对薄膜的形貌和金刚石的合成的影响。研究结果表明：在放电电压低于2kV时，薄膜主要由无序石墨和无定形碳组成。提高放电电压有助于金刚石的合成，在高的放电电压下，降低甲醇溶液浓度有利于提高碳膜中金刚石成分的含量。     

水热法合成具有汞(Ⅱ)识别能力的荧光碳点

以柠檬酸和酪蛋白为原料,采用水热法一步合成荧光碳点。所合成的碳点在350 nm激发波长下的荧光量子产率为48.9%,透射电镜显示荧光碳点呈球形,平均粒径为2.5 nm,红外光谱结果表明碳点表面含有羧基和氨基等活性基团,在水溶液中Hg(Ⅱ)对荧光碳点表现出选择性猝灭效果,基于此种现象建立了检测Hg(Ⅱ)的新方法。     

介孔碳/聚苯胺修饰电极的制备及其对Cu~(2+)的响应研究(英文)

制备了一个新的电极-聚苯胺掺杂介孔碳修饰电极(PANI-MC),并且研究了电极的电化学性质。在介孔分子筛SBA-15的孔道中沉积蔗糖,然后在氮气的保护下,1200℃热裂解,生成孔道规则排列的介孔碳(MC);XRD、N2吸附-脱附、TEM等方法表征了介孔碳的结构,用SEM表征了PANI-MC修饰电极的形貌。结果表明:复合电极膜与修饰前的聚苯胺膜形貌不同,与介孔碳形貌相似,介孔碳纳米微粒的大小清洗可辨,长度大约为20~40μm。复合电极循环伏安结果显示:峰电位向负电位方向移动,这可能是因为介孔碳的孔道结构阻碍了离子的转移。同时,还研究了复合电极对Cu2+的相应,表明:电极对低浓度的Cu2+有很好的线性相应,可以作为Cu2+的感应器。     

A viable way to tailor carbon nanomaterials by irradiation-induced transformations

Since the discovery of carbon nanotubes (CNT), transmission electron microscopy (TEM) has been the most important tool in their investigation. It is possible to use electron irradiation in a TEM to construct a single-walled carbon nanotube (SWCNT) from an amorphous carbon film. Here we show that such a synthesis method creates a large number of carbon ad-atoms, which after some critical amount of radiation act to restore the system by reconstructing the carbon film. The behavior of the ad-atoms can be controlled by adjusting the current density in the microscope, suggesting that carbon nanomaterials can be tailored by electron irradiation.     

Investigation of surface topography, morphology and structure of amorphous carbon films by AFM and TEM

Morphology and structure of amorphous carbon films deposited with a pulsed arc source (LASER-ARC) have been studied using microscopical methods (SEM, TEM and AFM), electron diffraction and spectroscopical investigation (EELS). The parameters of the arc source and the deposition conditions (substrate temperature) influence morphology and structure of deposited amorphous carbon films. Especially the incorporation and growth of particles, embedded in the film have been investigated. By particle analysis using an optical microscope a majority of particles that is smaller than 500 nm has been determined. The morphology has been also demonstrated similar by AFM and TEM images. Their number and size of particles is strongly influenced by the deposition temperature. The structure of amorphous film is characterized by the EELS-spectra, but the particle structure was not detectable.     

HDPE,LLDPE或LDPE高取向薄膜微结构的电子显微学研究

木工作用透射电子显微术及电子衍射技术研究3种PE(HDPE,LLDPE或LDPE)均聚物高取向薄膜的微结构。定量测定了它们的结晶尺寸。通过倾斜样品电子显微学研究确定了不同种PE纤维结构的对称性。     

硅丙型核壳结构乳胶粒子的制备及成膜过程

采用分步乳液聚合方法, 分别在不同步骤中将乙烯基硅氧烷单体作为共聚单体引入聚丙烯酸酯类乳液共聚合体系中, 制备出具有窄分布多层核壳结构形态的硅丙型乳胶粒子. 利用透射电子显微镜(TEM)表征, 乳胶粒子具有硅丙型核壳结构; 动态激光散射(DLS)分析得到的乳胶粒子的直径与TEM数据相符; 同时由多频调制差示扫描量热(TOPEM-DSC)技术分析得到的乳胶粒子的3个玻璃化转变温度与实验设计相符, 证实乳液粒子的核壳结构; 利用Horus成膜仪对乳胶粒子成膜过程进行全程监控. 利用多种助剂制得水性木器涂料, 其漆膜的硬度、耐丙酮性、耐水性、耐醇性及耐压痕等性能优异.     

Electrochemical Properties of Ordered Mesoporous Carbon Film Adsorbed onto a Self‐Assembled Alkanethiol Monolayer on Gold Electrode

A stable ordered mesoporous carbon (OMC) film electrode was successfully constructed by adsorbing OMC onto a self‐assembled monolayer (SAM) of C₁₈H₃₇SH chemisorbed on the Au electrode. Transmission electron microscopy (TEM), atomic force microscopy (AFM), and electrochemical methods were used to characterize the properties of the OMC film electrode. The adsorbed OMC can restore the heterogeneous electron transfer almost totally blocked by the alkanethiol monolayer. Nyquist plots show a sharply decrease of the charge transfer resistance (R_ct) of the Fe(CN) couple at the OMC film electrode. Furthermore, the OMC film electrode is found to possess a significantly reduced interfacial capacitance and largely enhanced current response of hydrogen peroxide. This novel approach to the fabrication of stable OMC film electrode with excellent electrochemical properties is believed to be very attractive for electrochemical studies and electroanalytical applications.     

乙腈中电化学法制备类金刚石薄膜

利用液相电沉积的方法在1600V,60℃条件下,从乙腈中沉积出类金刚石薄膜,发现了电流密度随反应时间呈波动变化的规律,并利用原子力显微镜和透射电子显微镜对薄膜不同生长阶段的形貌进行了考察.     

Development of an Integrated System for Immobilization and Mediating Charge to Alcohol Dehydrogenase During Bioelectrocatalytic Oxidation and Detection of Ethanol

A robust biocatalytic electrode film utilizing multiwalled carbon nanotubes intentionally derivatized with poly(diallyldimethylammonium chloride), PDDA, as well as integrated with alcohol dehydrogenase is considered here for potential application as a stable efficient anode in a biofuel cell and a specific working electrode in amperometric sensors. PDDA‐modified CNTs were characterized using transmission electron microscopy (TEM) and infrared spectroscopy (FTIR). Once immobilized on a glassy carbon electrode substrate, they facilitate not only distribution of charge but also immobilization of alcohol dehydrogenase molecules. The resulting integrated bioelectrocatalytic system was able to induce oxidation of ethanol and NADH as well as to produce relatively high currents at a fairly low potential.     

Electron‐Beam Irradiation in TEM of Hard‐Segment Homopolymers and Polyurethanes with Different Hard‐Segment Content

Summary: A hard‐segment homopolymer (HSH) and segmented poly(ester urethanes) (PESU) were studied by TEM to estimate their stability against electron‐beam irradiation. The bright‐field image and electron‐diffraction modes in TEM and optical polarised microscopy were used. It is shown that both soft and hard segments are sensitive to the electron beam. None of the films was stable enough to register an electron‐diffraction pattern without damage.

Electron‐diffraction pattern taken from the film of hard‐segment homopolymer crystallised at 100 °C from DMF: (a) the pattern registered immediately; (b) the pattern registered after 5 s of exposure in the TEM at the same place.     

Effects of carbon nanotube functionalization on the agglomeration and sintering of supported Pd nanoparticles

The size of carbon nanotube supported Pd and PdO nanoparticles was investigated on oxidatively functionalized multiwall carbon nanotubes. All samples were characterized by transmission electron microscopy, X-ray diffractometry, X-ray photoelectron spectroscopy and Raman spectroscopy. The average particle diameter calculated from TEM image analysis was found to be inversely proportional with the duration of the oxidation in nitric acid. Crystallite sizes determined from XRD patterns confirmed this general tendency.     

石墨烯/类金刚石碳复合薄膜的电化学沉积及其场发射性能

采用液相电化学方法在硅基底上制备了石墨烯掺杂的类金刚石碳复合薄膜,探讨了电化学沉积复合薄膜的机理。利用扫描电子显微镜（SEM）、拉曼光谱（Raman）、透射电子显微镜（TEM）和傅里叶变换红外（FTIR）光谱技术对薄膜表面形貌和微观结构进行了分析表征。结果表明,石墨烯片均匀分散沉积在含氢类金刚石碳（a-C：H）基体中,沉积的石墨烯/类金刚石（G/a-C：H）复合薄膜表面相对均匀平整。场发射测试显示石墨烯掺杂使开启电场从4.7 V·μm^-1增加至5.8 V·μm^-1,场发射电流密度从384 μA·cm^-2显著增加至876 μA·cm^-2。