辣根过氧化物酶在多壁碳纳米管——壳聚糖膜中的电化学和生物传感性质

采用壳聚糖包裹的多壁碳纳米管膜固定辣根过氧化物酶(HaP)于玻碳电极表面,实现了HRP的直接电化学并以此酶膜制备了NO生物传感器.在磷酸缓冲溶液中固定在电极表面的HRP氧化还原式电位为-0.354 V(us.SCE),直接电子转移速率常数为4.24±1.02 s-1.研究结果表明,固定在电极表面的HRP能保持其对一氧化氮还原的生物电催化活性,该传感器在NO浓度为1.0×10-4~1.4×10-3 mol L-1范围内存在线性响应,响应时间小于11 s,NO的检出限为7×10-4 mol L-1.多壁碳纳米管特殊的电学性质和壳聚糖良好的生物相容性性使得构筑的HRP生物传感器呈现了良好的应用前景,尤其适用于痕量NO的检测.     

壳聚糖-多壁碳纳米管/二茂铁修饰玻碳电极的电催化研究

利用多壁碳纳米管(MWCNTs)分散在壳聚糖/二茂铁形成的混合溶液,采用滴涂法对玻碳电极进行修饰,对多巴胺(DA)进行测定。结果表明,修饰后的玻碳电极能够有效促进DA在电极表面的电子传递速率,并且修饰电极对DA具有很好的催化氧化作用。DA氧化峰电流与其浓度在0.5～25μmol/L范围内呈良好的线性关系,检出限为3.89×10-7mol/L,并且常见物质对DA检测无干扰,DA注射液样品检测回收率为98.1%～100.9%。     

血红蛋白在碳纳米管/离子液体/纳米金修饰电极上的电化学特性及对过氧化氢的电催化分析

用碳纳米管/离子液体/纳米金修饰电极,构建了一种用于固定血红蛋白的新型复合材料,并对其形貌和电化学行为进行了表征。紫外光谱分析表明,血红蛋白在该复合膜内能很好地保持其原有的二级结构。采用循环伏安法和计时电流法对生物传感器的性能进行了研究。讨论了多壁碳纳米管(MWCNTs)用量、氯金酸浓度、电沉积时间对电极响应的影响,结果表明传感器对H2O2表现出良好的电催化性能。     

对硝基酚在β-环糊精/碳纳米管修饰电极上的电催化行为研究

以酸化处理的多壁碳纳米管与β环糊精为原料,采用静电自组装法制备了β环糊精/多壁碳纳米管复合材料。用循环伏安法研究了pH值、扫描速率、催化时间、原料比例、待测液浓度等因素对β环糊精/多壁碳纳米管修饰电极在对硝基酚溶液中电化学催化效果的影响。实验结果表明,β环糊精/多壁碳纳米管复合材料对对硝基酚电催化效果明显,且该催化过程为吸附控制过程。确定了最佳催化条件为选取邻苯二甲酸氢钾作为缓冲溶液,极化时间40s,碳纳米管与环糊精质量比为1∶3。对硝基酚浓度在1.3×10-6~3.5×10-4 mol/L时,对硝基酚的浓度与差分脉冲峰电流呈线性关系,相关系数为0.9985,检出限为1.223×10-7 mol/L。     

(Pt/Sn)-碳纳米管复合物的电催化性能

以碳纳米管(Carbon nanotubes,CNTs)为载体、乙二醇和甲酸钠为还原剂,采用浸渍法制备了不同Pt/Sn原子比的(Pt/Sn)-CNT复合物.通过X-射线衍射(XRD)和透射电子显微镜(TEM)对碳纳米管负载金属颗粒过程中的显微结构变化进行了研究.结果表明:Pt、Sn粒子在碳纳米管上高度分散,粒径分布在3.5nm～6.5nm之间,Sn元素以Pt-Sn合金和SnO2结构存在.循环伏安(CV)测试表明:Pt/Sn原子比为2.5:1～3.5:1时,(Pt/Sn)-CNT复合物的催化活性和抗毒化能力最佳.(Pt/Sn)-CNT复合物中CNTs保持了完整结构,对Pt、Sn粒子起到了稳定性作用,有利于提升(Pt/Sn)-CNT复合物对甲醇的氧化活性.     

氨基-β-环糊精/二茂铁/羧化单壁碳纳米管修饰的玻碳电极对多巴胺的电化学研究

对单壁碳纳米管进行羧化处理,然后将羧化的碳纳采管(SWCNTs)分散在氨基-β-环糊精(CD)/二茂铁(Fc)中形成混合溶液,并通过滴涂法利用该混合溶液制备修饰电极,用循环伏安法研究多巴胺(DA)在不同条件下的电化学行为.结果表明,经氨基-β-环糊精/二茂铁/羧化单壁碳纳米管修饰后的玻碳电极能够有效提高多巴胺在电极表面的电子传递速率,对多巴胺具有很好的催化氧化作用.     

辣根过氧化物酶在碳纳米管上的固定化及其固定化酶去除苯酚的研究

本文选用碳纳米管（CNTs）为载体,采用共价结合法,使用EDC／NHs交联剂将辣根过氧化酶（HRP）固定在CNTs上得到辣根过氧化酶固定化酶（HRP@CNTs）,系统研究了HRP的固定化条件,并考察了HRP@CNTs对苯酚的去除。HRP在CNTs上的最佳固定化条件是：HRP的固载量为7．5mg／gCNTs,温度为室温,固定化时间为15min。所得HRP@CNTs对苯酚的去除在20min内就可以进行完全,苯酚去除率达到78％。HRP@CNTs经过四次循环使用后对苯酚的去除率仍然可以保持为新鲜HRP@CNTs的1／3。此外,与自由的HRP相比,HRP@CNTs在PBS缓冲溶液中的储存稳定性显著增加,4℃条件下储存60天后,HRP@CNTs对苯酚的去除率几乎不变。     

纳米材料过氧化物模拟酶在比色分析及电化学传感器中的应用

纳米材料模拟酶与天然酶相比,稳定性好,反应活性较高,易于对各类功能分子或蛋白质等进行修饰和标记,能够方便地应用于生物分析检测中.近几年,国内外的研究人员制备出各种各样的新型纳米材料模拟酶用于过氧化氢、葡萄糖、癌症标志物的检测.简要总结了近年来国内外磁性纳米粒子、金属纳米粒子、纳米合金等纳米材料模拟酶在比色分析及电化学传感器中应用的研究进展.     

聚中性红/铁氰化镍/碳纳米管修饰电极的制备及其电催化过氧化氢的特性

采用循环伏安法在碳纳米管(CNTs)修饰的玻碳电极上合成聚中性红(PNR)/铁氰化镍(NiHCF)颗粒,并分别采用扫描电镜(SEM)、傅里叶红外(FTIR)、循环伏安法(CV)和计时安培电流法(CA)等方法考察了复合膜的微观形貌、结构和电化学催化性能。结果表明,复合膜为三维多孔有序的网络状结构,PNR和NiHCF以纳米颗粒形式存在并沿CNTs均匀分布。PNR/NiHCF/CNTs复合膜对过氧化氢(H2O2)表现出了优异的电催化性能并显示出了良好的协同效应。该复合膜电极对H2O2的催化还原电流与其浓度在6.25×10-6~3×10-3之间呈良好的线性关系,线性相关系数R=0.9989,检出限为1×10-7mol/L,同时具有较高的灵敏度1 455.9 mA·L/(mol·cm2),并且复合膜有良好的稳定性和重现性,可实际应用于H2O2传感器。     

碳纳米管和壳聚糖的层层静电自组装多层膜(英文)

将多壁碳纳米管(MWCNT)置于混酸(硝酸∶硫酸=1∶3)中,利用超声波振荡截短碳纳米管、并使其与羧基链接,而后基于阳离子聚合电解质壳聚糖(CS)和阴离子短切碳纳米管之间的静电作用,在玻璃衬底上通过层层的模式均匀稳定地自组装形成复合壳聚糖多层膜。UV-vis光谱显示:组装过程呈现均匀而连续的生长。AFM和SEM观察表明:CS/MWCNT多层膜具有良好的光学特性,在生物传感器方面具有潜在的应用前景。     

Comparative electrochemistry of haemoglobin on the long and ball milling shortened carbon nanotubes

Short multi-walled carbon nanotubes (S-MWCNTs) were obtained by ball milling method and employed as a supporting matrix to explore a novel immobilisation and biosensing platform of redox proteins such as haemoglobin (Hb). Compared to long MWCNTs, the shortened MWCNTs-based biosensor did not show better electrocatalytic activity, which was contrary to previous theoretical expectations. The electron transfer rate constants of Hb on long and short MWCNTs modified electrodes in phosphate buffer solution were 1.08 and 0.95?s^?1, respectively. The lower electron transfer rate between haemoglobin and the electrode can be attributed to their larger resistive properties, which were confirmed by cyclic voltammetry and AC impedance.     

单壁碳纳米管束的排布

流体排布法是实现碳纳米管定向排列的一种简单的方法。采用流体排布法在具有浸润性图案化的基底上成功地对单壁碳纳米管(SWNTs)束进行了水平方向上的排布。将SWNTs悬浮液滴入光刻胶制成的微通道中,在流体剪切力作用下,弯曲的SWNTs在一定程度上会被拉伸并且平行地排列在纳米级宽度的微通道中。将排列好的SWNTs阵列转移到一些不同间距的金电极对上面,制作成碳纳米管场效应晶体管(CNTFET)。CNTFET的电性能测试结果表明,制备的SWNTs束可以制造出不同电极间距同时具有良好电性能的CNTFET。     

Ball-milling modification of single-walled carbon nanotubes: purification, cutting, and functionalization

Single-walled carbon nanotubes (SWNTs) can be successfully cut with relatively homogeneous sizes using a planetary mill. The optimized conditions produce highly dispersible SWNTs that can be efficiently functionalized in a variety of synthetic ways. As clearly shown by Raman spectroscopy, the milling/cutting procedure compares very favorably with the most common way of purifying SWNTs, namely, treatment with strong oxidizing acids. Moreover a similar milling process can be used to functionalize and cut pristine SWNTs by one-step nitrene chemistry.     

Direct discrimination between semiconducting and metallic single-walled carbon nanotubes with high spatial resolution by SEM

Single-walled carbon nanotube (SWCNT) films with a high density exhibit broad functionality and great potential in nanodevices,as SWCNTs can be either metallic or semiconducting in behavior.The films greatly benefit from characterization technologies that can efficiently identify and group SWCNTs based on metallic or semiconducting natures with high spatial resolution.Here,we developed a facile imaging technique using scanning electron microscopy (SEM) to discriminate between semiconducting and metallic SWCNTs based on black and white colors.The average width of the single-SWCNT image was reduced to ～9 nm,～1/5 of previous imaging results.These achievements were attributed to reduced surface charging on the SiO2/Si substrate under enhanced accelerating voltages.With this identification technique,a CNT transistor with an on/off ratio of ＞105 was fabricated by identifying and etching out the white metallic SWCNTs.This improved SEM imaging technique can be widely applied in evaluating the selective growth and sorting of SWCNTs.     

Scanning electron microscopy imaging of single-walled carbon nanotubes on substrates

Scanning electron microscopy (SEM) plays an indispensable role in nanoscience and nanotechnology because of its high efficiency and high spatial resolution in characterizing nanomaterials.Recent progress indicates that the contrast arising from different conductivities or bandgaps can be observed in SEM images if single-walled carbon nanotubes (SWCNTs) are placed on a substrate.In this study,we use SWCNTs on different substrates as model systems to perform SEM imaging of nanomaterials.Substantial SEM observations are conducted at both high and low acceleration voltages,leading to a comprehensive understanding of the effects of the imaging parameters and substrates on the material and surface-charge signals,as well as the SEM imaging.This unified picture of SEM imaging not only furthers our understanding of SEM images of SWCNTs on a variety of substrates but also provides a basis for developing new imaging recipes for other important nanomaterials used in nanoelectronics and nanophotonics.     

Prediction of nonlocal scaling parameter for armchair and zigzag single-walled carbon nanotubes based on molecular structural mechanics, nonlocal elasticity and wave propagation

Atomic vibration in the Carbon Nanotubes (CNTs) gives rise to non-local interactions. In this paper, an expression for the non-local scaling parameter is derived as a function of the geometric and electronic properties of the rolled graphene sheet in single-walled CNTs. A self-consistent method is developed for the linearization of the problem of ultrasonic wave propagation in CNTs. We show that (i) the general three-dimensional elastic problem leads to a single non-local scaling parameter (e₀), (ii) e₀ is almost constant irrespective of chirality of CNT in the case of longitudinal wave propagation, (iii) e₀ is a linear function of diameter of CNT for the case of torsional mode of wave propagation, (iv) e₀ in the case of coupled longitudinal-torsional modes of wave propagation, is a function which exponentially converges to that of axial mode at large diameters and to torsional mode at smaller diameters. These results are valid in the long-wavelength limit.     

Selective adsorption of cations on single-walled carbon nanotubes: A density functional theory study

The selective adsorption of cation on single-walled carbon nanotubes (SWNTs) is systemically studied by using density functional theory calculations. It is found that the adsorption energy of cations on SWNTs depends on the concentration of cations and the diameter and the electronic structure of SWNTs. The binding strength of on each SWNT increases monotonically as the concentration of decreases, undergoing a change from endothermic to exothermic reaction. Generally speaking, the binding of on SWNTs becomes weaker as the diameter increases. In the medium-diameter region (9 < d < 11 Å), prefers to interact with metallic SWNTs (m-SWNTs) rather than semiconducting SWNTs (s-SWNTs) at the same concentration of . In the small-diameter region (d < 9 Å), the binding of is nearly independent of metallicity, but it is stronger than that of on the medium-diameter s-SWNTs. In the large-diameter region (d > 11 Å), the dependence of adsorption on the electronic structure is complicated, but the binding of is weaker than that on the medium-diameter s-SWNTs. Our results are in agreement with the experimental report that the small-diameter m- and s-SWNTs and the medium-diameter m-SWNTs are etched away by while the medium-diameter s-SWNTs and the large-diameter m- and s-SWNTs are intact.     

碳纳米管担载纳米银及其电催化甲醇氧化的研究

以水溶性离聚物聚（苯乙烯磺酸钠-co-丙烯酸）（PSA）接枝多壁碳纳米管为模板,制备了碳纳米管担载纳米银（AgNP@MWNT）,研究了在碱性条件下对甲醇氧化的电催化作用。结果表明接枝在MWNT表面的离聚物PSA有效地控制了AgNP在MWNT表面以2～4nm的尺寸均匀担载,促进了AgNP与MWNT之间的界面相互作用。制备的Ag@MWNT在水中能够稳定地均匀分散,在碱性条件下可有效地电催化甲醇氧化,抗甲醇中毒性能良好。