共查询到17条相似文献,搜索用时 64 毫秒
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利用PVK-NH2和酰氯化的多壁碳纳米管(MWNTs)之间的酰胺化反应制备了聚乙烯咔唑共价接枝的碳纳米管杂化材料MWNT-PVK。该材料在许多常见的有机溶剂中具有良好的溶解度。在514.5nm激光的激发下,观察到的D-带和G-带强度比(ID/IG)分别从MWNTs的0.96增加到MWNT-COOH的1.05再增加到MWNT-PVK的1.19,这意味着羧基和PVK分别共价接枝到MWNTs的表面。PVK在MWNTs上的共价接枝导致了PVK的荧光强度大幅度下降,这种荧光淬灭现象,说明了在材料体系中处于激发单重态的MWNTs与给电子的PVK之间可能发生了电荷转移现象。 相似文献
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采用循环伏安法和悬凃法,在玻碳电极表面进行聚(3,4)-乙撑二氧噻吩(PEDOT)和多壁碳纳米管修饰,制备多壁碳纳米管-聚(3,4)-乙撑二氧噻吩复合修饰电极。通过扫描电镜观察复合电极的表面形貌,通过电化学阻抗谱(EIS)和循环伏安(CV)对复合电极进行电化学表征,用差分脉冲法(DPV)研究对苯二酚浓度与峰电流之间的线性关系。实验结果表明,制备的复合修饰电极对对苯二酚有明显的电催化作用,氧化还原峰电流明显增大;在p H为7.0的磷酸缓冲液(PBS)里,对苯二酚的峰电流最大。在1×10-5~5×10-4mol/L对苯二酚的浓度范围内,复合修饰电极的氧化峰电流值与浓度呈线性关系,其线性方程为y=47.95+0.097 9x,R2=0.961,检出限为1.9×10-6mol/L。制备的复合修饰电极能够增强电化学信号,具有较好的稳定性。 相似文献
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分别采用聚羧酸减水剂、聚乙烯吡咯烷酮(PVP)、洗衣粉(XYF)等3种表面活性剂并结合超声波分散方法,研究了多壁碳纳米管(MWCNTs)在水中和水泥浆中的分散性及其对水泥强度的影响,采用人工观察和扫描电子显微镜分别评价了MWCNTs在水中的分散性和在水泥硬化体中的分布情况。结果表明:单独采用减水剂为分散剂并在超声波分散条件下,MWCNTs在水中和水泥浆中容易发生团聚,无法起到增强作用;在超声波分散作用下,采用PVP和XYF为分散剂能够显著提高MWCNTs在水中和水泥浆中的分散性,PVP大幅度提高了水泥硬化体强度,但XYF却使强度大幅度降低,这是因其具有的较强起泡功能使水泥硬化体中的气泡量增加、气孔尺寸提高,并形成一些较大孔隙,从而显著降低了水泥石的密实性。 相似文献
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《应用化工》2017,(10):2048-2052
运用线性扫描伏安法(LSV)研究了磺胺(SA)在多壁碳纳米管修饰电极(MWNTs/GCE)上的电化学行为,探讨并确定了修饰体积和浓度、支持基质种类、最佳pH值、富集电位和时间等磺胺的最佳检测条件。结果表明,在pH=8.0的Na2HPO4-NaH2PO4缓冲体系中,磺胺在多壁碳纳米管修饰电极上检测到一个不可逆的氧化峰,且在1.0×10-5~2.0×10-4mol/L浓度范围内,磺胺氧化峰电流与其浓度呈现良好的线性关系,线性回归方程为Ip(μA)=0.493 6×C(μmol/L)+9.984 1,相关系数为R=0.996 3,检测下限为8.0×10-6mol/L,平行测定的相对误差(RSD)小于1.463%(n=8),样品平均加标回收率为99.21%~100.93%。 相似文献
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《应用化工》2022,(10):2048-2052
运用线性扫描伏安法(LSV)研究了磺胺(SA)在多壁碳纳米管修饰电极(MWNTs/GCE)上的电化学行为,探讨并确定了修饰体积和浓度、支持基质种类、最佳pH值、富集电位和时间等磺胺的最佳检测条件。结果表明,在pH=8.0的Na2HPO4-NaH2PO4缓冲体系中,磺胺在多壁碳纳米管修饰电极上检测到一个不可逆的氧化峰,且在1.0×10-52.0×10-4mol/L浓度范围内,磺胺氧化峰电流与其浓度呈现良好的线性关系,线性回归方程为Ip(μA)=0.493 6×C(μmol/L)+9.984 1,相关系数为R=0.996 3,检测下限为8.0×10-6mol/L,平行测定的相对误差(RSD)小于1.463%(n=8),样品平均加标回收率为99.21%2.0×10-4mol/L浓度范围内,磺胺氧化峰电流与其浓度呈现良好的线性关系,线性回归方程为Ip(μA)=0.493 6×C(μmol/L)+9.984 1,相关系数为R=0.996 3,检测下限为8.0×10-6mol/L,平行测定的相对误差(RSD)小于1.463%(n=8),样品平均加标回收率为99.21%100.93%。 相似文献
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An original image analysis method is presented to characterize multi-walled carbon nanotubes from transmission electron microscopy images. The analysis is performed in three steps: (i) image preprocessing in order to isolate the nanotubes from the background, (ii) image segmentation, aiming at keeping only the measurable sections of nanotubes, and finally (iii) tube characteristics measurement. The measurement is based on a Lambert-like electron absorption law and is performed on the original gray level image itself. Two geometrical and one physical characteristics are determined for each tube, namely, its outer and inner radius and a linear electron absorption coefficient. The method is illustrated by comparing a pristine and an annealed carbon nanotube samples. The compaction of the tube walls during annealing is shown to result from a lowering of the external radius while the inner radius is left unchanged. 相似文献
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Lixiang Li 《Carbon》2005,43(3):623-629
Double-walled carbon nanotubes (DWNTs) were synthesized in a large scale by a hydrogen arc discharge method using graphite powders or multi-walled carbon nanotubes/carbon nanofibers (MWNTs/CNFs) as carbon feedstock. The yield of DWNTs reached about 4 g/h. We found that the DWNT product synthesized from MWNTs/CNFs has higher purity than that from graphite powders. The results from high-resolution transmission electron microscopy observations revealed that more than 80% of the carbon nanotubes were DWNTs and the rest were single-walled carbon nanotubes (SWNTs), and their outer and inner diameters ranged from 1.75 to 4.87 nm and 1.06 to 3.93 nm, respectively. It was observed that the ends of the isolated DWNTs were uncapped and it was also found that cobalt as the dominant composition of the catalyst played a vital role in the growth of DWNTs by this method. In addition, the pore structures of the DWNTs obtained were investigated by cryogenic nitrogen adsorption measurements. 相似文献
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Zongnan Miao Zhennan Jia Zhi Yu Shaokang Chen Shengtai Zhou Pengbo Liu Huawei Zou 《应用聚合物科学杂志》2020,137(44):49357
In this study, a series of polyimide/multi-walled carbon nanotubes (PI/MWCNTs) composite aerogels with anisotropic properties were fabricated. First, the poly(amic acid) ammonium salt (PAS)/MWCNTs suspension was prepared by blending poly(amic acid), deionized water, triethylamine, MWCNTs, and CNT dispersant with the aid of ultrasonication treatment. Afterwards, the aqueous PAS/MWCNTs suspension was unidirectionally frozen at −65 ± 5°C, then followed by freeze-drying. Subsequently, the PI/MWCNTs composite aerogels were obtained after thermal imidization treatment. Morphology observations revealed that PI/MWCNTs composite aerogels exhibited a “hive-like” structure while viewed along the freezing direction, whereas a typical channel-like pore structure was observed perpendicular to the freezing direction. This typical structure rendered PI/MWCNTs composite aerogels with anisotropic properties such as heat conduction, electrical conductivity as well as electromagnetic interference shielding effectiveness when the aerogels were characterized at different directions. 相似文献
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Bo Gao 《Electrochimica acta》2010,55(7):2311-9232
Nanocomposite of benzenesulfonic functionalized multi-walled carbon nanotubes doped polyaniline (PANi/f-MWCNTs) was synthesized via a low-temperature in situ polymerization method. The PANi/f-MWCNTs composite has a thin film of PANi coating uniformly on the surface of the f-MWCNTs. The electrochemical results show that PANi/f-MWCNTs nanocomposite possesses good rate response, which could ascribe to the uniform structure and the better conductivity of composite as well as the in situ doping/de-doping process between the benzenesulfonic acid groups of f-MWCNTs and PANi chain. In addition, the composite also has better capacity and cyclability than PANi/p-MWCNTs composite. It could attribute to the presence of f-MWCNTs, which makes more electrolyte contact with PANi to participate in faradaic redox reactions and dopes with the PANi polymer chain through the benzenesulfonic acid groups to form stable polyemeraldine salts. 相似文献
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Preparation and characterization of multi-walled carbon nanotubes supported PtRu catalysts for proton exchange membrane fuel cells 总被引:1,自引:0,他引:1
A series of PtRu nanocomposites supported on H2O2-oxidized multi-walled carbon nanotubes (MWCNTs) were synthesized via two chemical reduction methods—one used aqueous formaldehyde (HCHO method) and the other used ethylene glycol (EG method) as the reducing agents. The effects of the solvents (water and ethylene glycol) and the surface composition of the MWCNTs on the deposition and the dispersion of the metal particles were investigated using N2 adsorption, TEM, ICP-AES, FTIR and TPD. The wetting heats of the MWCNTs in corresponding solvents were also measured. The characterizations suggest that combination of the surface chemistry of the MWCNTs with the solvents decides the deposition and the dispersion of the metal nanoparticles. These nanocomposites were evaluated as proton exchange membrane fuel cell anode catalysts for oxidation of 50 ppm CO contaminated hydrogen and compared with a commercial PtRu/C catalyst. The data reveal superior performances for the nanocomposites prepared by the EG method to those by the HCHO method and even to that for the commercial analogue. Structure–performance relationship of the nanocomposites was also studied. 相似文献