Fe3O4纳米粒子修饰碳纳米管的制备及其磁学性能（英文）

通过FeCl2.4H2O和FeCl3.6H2O混合共沉淀,合成平均粒径为6 nm和10 nm的Fe3O4纳米粒子。然后将两种Fe3O4纳米粒子分别与经HNO3氧化处理的多壁碳纳米管(MWCNTs)置于乙醇水溶液(水和乙醇的体积比为1∶1)中,在超声波作用下制备Fe3O4/MWCNT复合材料。用高分辨透射电子显微镜、X-射线光电子能谱、振动样品磁强计、X射线衍射仪、热重分析仪对所制备的Fe3O4/MWCNT复合材料进行表征。结果表明:由6 nm和10 nm Fe3O4纳米粒子所制备的Fe3O4/MWCNT复合材料中,Fe3O4的质量分数分别为26.65%和29.3%,相应的磁饱和强度分别为16.5 emug-1和7.5 emug-1。     

锂离子电池正极材料LiNi0.5FexMn1.5-xO4的电化学性能

以醋酸锂、醋酸锰、醋酸镍、草酸铁为原料,采用溶胶凝胶法制备出了4.6 V高电位材料LiNi0.5-FexMn1.5-xO4。合成化学计量比为n(Li)∶n(Mn)∶n(Ni)∶n(Fe)=1.3∶1.5-x∶0.5∶x(x=0,0.02,0.03,0.04)。在空气条件下于450℃下煅烧6h,再于800℃下烧结18h。对合成的材料用X射线衍射仪分析晶体结构和用扫描电镜(SEM)观察微观形貌,对电池进行首次充放电测试和循环效率测试。实验结果表明,LiNi0.5FexMn1.5-xO4三元正极材料为立方晶系,Fd3m空间群。以其为正极材料组装的锂离子电池在x=0.03时,充放电比容量为126mA·h·g-1。     

Preparation of porous chromium oxide nanotubes using carbon nanotubes as templates and their application as an ethanol sensor

Chromium oxide nanotubes were successfully prepared using multi-walled carbon nanotubes (MWCNTs) as a template via a supercritical fluid-mediated route. In this method, with chromium (III) nitrate nonahydrate as precursor, chromium oxide was first deposited on MWCNTs in supercritical ethanol in the presence of NH(4)HCO(3). The as-prepared chromium oxide/MWCNT nanocomposites were characterized by transmission electron microscopy, x-ray diffraction, infrared spectroscopy and thermogravimetric analysis. It was demonstrated that the MWCNTs were coated with a layer of amorphous Cr(2)O(3)·xH(2)O. The thickness of the Cr(2)O(3)·xH(2)O sheath on MWCNTs could be tuned by manipulating the ratio of precursor to MWCNTs. Calcining the composites at 550?°C, the MWCNTs were removed, producing polycrystalline α-Cr(2)O(3) nanotubes. The as-prepared α-Cr(2)O(3) sample was used as a sensor material to detect ethanol vapor, and it was demonstrated that the α-Cr(2)O(3) nanotubes exhibited good performance even at 400?°C.     

From cobalt nitrate carbonate hydroxide hydrate nanowires to porous Co(3)O(4) nanorods for high performance lithium-ion battery electrodes

We have developed a simple approach for the large-scale synthesis of cobalt nitrate carbonate hydroxide hydrate (Co(CO(3))(0.35)(NO(3))(0.2)(OH)(1.1)·1.74H(2)O) nanowires via the hydrothermal process using sodium hydroxide and formaldehyde as mineralizers at 120?°C. The porous Co(3)O(4) nanorods 10-30?nm in diameter and hundreds of nanometres in length have been fabricated from the above-mentioned multicomponent nanowires by calcination at 400?°C. The morphology and structure of cobalt nitrate carbonate hydroxide hydrate nanowires and Co(3)O(4) nanorods have been characterized by transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM) and x-ray powder diffraction (XRD). Moreover, the porous Co(3)O(4) nanorods have been applied in the negative electrode materials for lithium ion batteries, which exhibit high electrochemical performance.     

聚乙烯/马来酸酐接枝聚合物修饰多壁碳纳米管

多壁碳纳米管(MWCNTs)与混酸(浓硫酸∶浓硝酸体积比为3∶1)和无水乙二胺进行酸化、胺化反应使MWCNTs表面产生羧基和氨基基团,进而与聚乙烯/马来酸酐接枝聚合物(PE-g-MA)发生开环反应制备PE-g-MWCNTs,以提高MWCNTs在聚乙烯基体中的分散性。采用红外光谱、X-射线光电子能谱(XPS)和拉曼光谱对MWCNTs的化学修饰进行定性表征。结果表明:当MWCNTs的体积分数为0.67%时,MWCNT/PE复合材料的体积电阻率发生渗流突变。MWCNTs的体积分数在0.1%～1.2%时,MWCNT/PE复合材料体积电阻率由1016Ω.m下降至105Ω.m。     

锂离子电池正极材料Li3V2-2x/3Mnx（PO4）3的溶胶凝胶法合成和电化学性能

以CH3COOLi·2H2O、V2O5、Mn(CH3COO)2·4H2O、(NH4)2HPO4和蔗糖为原料,采用溶胶–凝胶法合成了掺锰磷酸钒锂/碳(Li3V2-2x/3Mnx(PO4)3/C)复合正极材料,用XRD、XPS、SEM、电化学性能对样品进行了表征.测试结果表明,少量锰的掺杂并未改变Li3V2(PO4)3/C的单斜结构,Li3V1.94Mn0.09(PO4)3中的Mn和V分别以+2和+3价存在,其颗粒类似球形,直径比较均匀且小于200 nm,并表现出良好的电化学性能.在0.1C倍率和3.0～4.8 V电压内,该样品的首次充、放电容量分别为182.1和168.8 mAh/g,放电效率高达92.69%,而且100次循环后,其放电比容量仍是首次放电容量的77.4%.     

MWCNT/PEDOT复合材料的微观结构和热电性能

热电转换技术能将大量的废弃热能转换为电能以重新利用,是一种绿色能源转换技术,可以有效提高能源利用效率,缓解煤炭、石油等主要化石类能源过度开采、使用带来的能源危机及环境污染问题,因此受到科研工作者的广泛关注,是近年来的研究热点。基于此,本文以电子型导电高聚物中机能较优的聚(3, 4-乙烯二氧噻吩)(PEDOT)作为研究主体,通过化学原位氧化聚合将多壁碳纳米管(MWCNT)复合到载体中得到MWCNT/PEDOT复合材料。利用XRD、拉曼、TEM及正电子湮没寿命(PAL)等方法对MWCNT/PEDOT复合材料的形貌和微观结构进行了系统研究,研究表明:当MWCNT含量高于24.9wt%时,复合材料中出现MWCNT团聚现象,其分散性变差。同时,MWCNT/PEDOT复合材料的热电性能测试结果显示,未掺杂PEDOT的电导率仅为7.5 S·m?1,而MWCNT含量为30.1wt%时,该复合材料的电导率高达566.59 S·m?1,提高近76倍。同时,30.1wt%MWCNT/PEDOT的功率因子(814.3×10?4 μW·(m·K2)?1)相对于未掺杂PEDOT(14.5×10?4 μW·(m·K2)?1)提高约56倍,这主要是由于PEDOT分子链与MWCNT掺杂物间π-π相互作用及MWCNT的高导电性。随着MWCNT含量的增加,PAL测试结果中第一寿命成分τ₁(即正电子在材料中湮没的第一寿命成分)的下降证实了该复合材料中MWCNT与PEDOT间界面变小或者界面间相互作用减弱,导致其热导率相对于未掺杂PEDOT有一定的上升,但远远低于功率因子的升高。最终,该MWCNT/PEDOT复合材料的热电优值(即热电材料Z_T值)由0.015×10?4升至0.45×10?4,增加了约30倍。结果表明:掺杂的高电导率MWCNT能够极大地提高PEDOT类电子型导电聚合物的热电性能。      

Amplified electrochemical detection of a cancer biomarker by enhanced precipitation using horseradish peroxidase attached on carbon nanotubes

An electrochemical nanoimmunosensor based on multiwall carbon nanotubes (MWCNTs)/gold nanoparticles (AuNPs) was developed for the amplified detection of prostate specific antigen (PSA). The amplified detection was achieved by the enhanced precipitation of 4-chloro-1-naphthol (CN) using a higher number of horseradish peroxidase (HRP) molecules attached on MWCNTs. The PSA nanoimmunosensor was fabricated by immobilizing a monoclonal anti-PSA antibody (anti-PSA) on the AuNP-attached thiolated MWCNT on a gold electrode. The sensor surface was characterized using scanning electron microscope, transmission electron microscope, quartz crystal microbalance, and electrochemical techniques. Cyclic and square wave voltammetric techniques were used to monitor the enhanced precipitation of CN that accumulated on the electrode surface and subsequent decrement in the electrode surface area by monitoring the reduction process of the Fe(CN)(6)(3-)/Fe(CN)(6)(4-) redox couple. Under the optimized experimental condition, the linear range and the detection limit of PSA immunosensor were determined to be 1.0 pg/mL to 10.0 ng/mL and 0.40 ± 0.03 pg/mL, respectively. The validity of the proposed method was compared with an enzyme-linked immunosorbent assay method in various PSA spiked human serum samples.     

Oxygen Barrier of Multiwalled Carbon Nanotube/Polymethyl Methacrylate Nanocomposites Prepared by in situ Method

Multiwalled carbon nanotubes (MWCNTs)/poly(methyl methacrylate) (PMMA) nanocomposites were prepared by ultrasonic assisted emulsifier free emulsion polymerization technique with variable concentration of functionalized carbon nanotubes. MWCNTs were functionalized with H 2 SO 4 and HNO 3 with continuing sonication and polished by H 2 O 2 . The appearance of Fourier transform infrared absorption bands in the PMMA/MWCNT nanocomposites showed that the functionalized MWCNT interacted chemically with PMMA macromolecules. The surface morphology of functionalized MWCNT and PMMA/MWCNT nanocomposites were studied by scanning electron microscopy. The dispersion of MWCNT in PMMA matrix was evidenced by high resolution transmission electron microscopy. The oxygen permeability of PMMA/MWCNT nanocomposites gradually decreased with increasing MWCNT concentrations.     

Microwave-assisted synthesis of ZnO/MWCNT hybrid nanocomposites and their alcohol-sensing properties

Zinc oxide and multi-walled carbon nanotube (ZnO/MWCNT) hybrid nanocomposites were synthesised by microwave-assisted method using the mixed solution of zinc acetate dehydrate (Zn(CH₃COO)₂·2H₂O) and treated MWCNTs. The syntheses were carried out at various microwave irradiation powers. The characterisation of the as-synthesised nanocomposites was conducted by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD results revealed that the composites were composed of two phases of MWCNTs and hexagonal wurzite ZnO. The SEM results showed that the ZnO nanoparticles were well decorated on the surface of MWCNTs. The amount of ZnO nanoparticles and their size increased with increasing irradiation power. Thick-film sensors were fabricated onto interdigitated conducting electrodes using as-synthesised hybrid composites as sensing materials. The alcohol-sensing behaviour of the hybrid composite films was investigated. The results indicated that the irradiation power had significant influence on the sensing response of the sensors toward alcohol. The sensor fabricated from the composite synthesised at higher irradiation power exhibited an enhanced alcohol-sensing performance.     

Multi-modal mesoporous TiO(2)-ZrO(2) composites with high photocatalytic activity and hydrophilicity

Utilizing the amphiphilic triblock copolymer Pluronic P123 as the surfactant, and Ti(O(n)Bu)(4) and ZrOCl(2)·8H(2)O as the inorganic sources, a series of multi-modal mesoporous TiO(2)-ZrO(2) composites have been successfully synthesized through a one-step method. The resultant materials were characterized in detail by x-ray diffraction, atomic force microscopy, high resolution scanning electron microscopy, transmission electron microscopy, N(2) adsorption and water contact angle measurements. The effect of calcination temperatures on the physical parameters, hydrophilicity and photocatalytic activity of the obtained mesoporous TiO(2)-ZrO(2) composites was also investigated in this paper.     

Poly(3- hydroxybutyrate)/Bioglass(®) composite films containing carbon nanotubes

Poly(3hydroxybutyrate) (P(3HB))/Bioglass(?)?composites incorporating multiwalled carbon nanotubes (MWCNTs) have been successfully prepared by the solvent casting technique. The microstructure, electrical properties and bioactivity of the composites were characterized using scanning electron microscopy, x-ray diffraction and current-voltage measurements. Different concentrations of MWCNTs were used to determine their effect on the electrical properties of the composites. MWCNTs and Bioglass(?) particles were found to be homogeneously dispersed throughout the P(3HB) matrix. The electrical resistance of the composite samples decreased on increasing the MWCNT concentration, as expected. An in vitro degradation study in simulated body fluid (SBF) was carried out on composite samples. The formation of hydroxyapatite on the surfaces of P(3HB)/Bioglass(?)/MWCNT composite films was confirmed after two months of immersion in SBF. This hydroxyapatite layer was not formed on the neat polymeric films and on composites containing MWCNTs only (without Bioglass(?)). It was found that the presence of MWCNTs did not hinder the bioactivity of the Bioglass(?) particles, as confirmed by SEM and XRD studies on composite samples.     

新型稀土荧光材料的合成及表征

合成了3种新型荧光材料Eu(o-OHC6 H4COO)2(phen)2(NO3)、Eu(p-OHC6 H4CH2COO)3(phen)和Eu(C6H5CHOHCOO)3(phen)(H2O),并通过元素分析、红外光谱、紫外光谱和荧光光谱对其进行了表征.通过对配合物荧光性能的研究,表明这3种配合物是较好的荧光材料.     

Preparation and properties of a carbon nanotube-based nanocomposite photoanode for dye-sensitized solar cells

This study fabricates dye-sensitized solar cells (DSSCs) based on TiO(2)/multi-walled carbon nanotube (MWCNT) nanocomposite photoanodes obtained by the modified acid-catalyzed sol-gel procedure. Results show that incorporating MWCNTs into a TiO(2)-based electrode efficiently improves the physicochemical properties of the solar cell. The results of dye adsorption and cell performance measurements indicate that introducing MWCNTs would improve the roughness factor (from?834 to?1267) of the electrode and the charge recombination of electron/hole (e(-)/h(+)) pairs. These significant changes could lead to higher adsorbed dye quantities, photocurrent and DSSC cell performance. Nevertheless, a higher loading of MWCNTs causes light-harvesting competition that affects the light adsorption of the dye-sensitizer, and consequently reduces the cell efficiency. This study suggests an optimum MWCNT loading in the electrode of 0.3?wt%, and proposes a sol-gel synthesis procedure as a promising method of preparing the TiO(2)-based nanocomposite.     

The poly(urethane-ionic liquid)/multi-walled carbon nanotubes composites

In the paper, a novel kind of imidazolium based poly(urethane-ionic liquid)/multi-walled carbon nanotubes (PUIL/MWCNT) composites was facilely prepared by uncovalent ways. The imidazolium based ionic liquid (IL) greatly improved the dispersion of pristine MWCNTs in PUIL by the π-cation interaction formed between the imidazolium cation and the π-electron of MWCNTs. The PUIL/MWCNT composites showed obviously increased modulus, glass transition temperature and tensile strength in comparison with PU/MWCNT composites. The thermal and mechanical properties of the PUIL/MWCNT composites presented significant increase with low load of the MWCNTs. It indicated the interactions between PUIL and MWCNTs played an important role to enhance the performances of the composites.     

A room temperature synthetic route to Mn3O4 nanoplates

Nanoplates of Mn3O4 were prepared by redox reactions of Mn(CH3COO)2 x 4H2O taking place in short chain n-alkylamine aqueous solutions such as n-butylamine, n-propylamine and n-hexylamine at room temperature. Phase purity was confirmed by powder X-ray diffraction. The high resolution transmission electron microscopy revealed the rectangle shape of Mn3O4 nanoplates with the average edge length of 22 nm and width of 19 nm. The prepared Mn3O4 nanoplates exhibited a coercive field of 5034 Oe at 10 K. The possible formation mechanism was also discussed.     

Synthesis and field electron emission properties of hybrid carbon nanotubes and nanoparticles

Hybrid ZnO-carbon nanotubes as well as nanodiamond-carbon nanotubes were synthesized via a straightforward process of plasma enhanced chemical vapor deposition. For the former, ZnO nanoparticles were instantly coated on the tube surface in the final growing process of carbon nanotubes, while for the latter diamond nanoparticles were grown using pretreatment of a silicon substrate with Ni(NO(3))(2)·6H(2)O/Mg(NO(3))(2)·6H(2)O alcohol solution prior to deposition and a high H(2)/CH(4) gas flow ratio in the deposition process. The morphology and microstructure of the obtained hybrid materials were characterized by transmission electron microscopy. Both hybrid ZnO-carbon nanotubes and nanodiamond-carbon nanotubes exhibited excellent field emission properties.     

Comparison of diatoms, exfoliated graphite, single-wall nanotubes, multiwall nanotubes, and silica for the synthesis of the nanomagnet Mn12

We have completed a preliminary series of experiments that compare the silicate shells of the marine organism diatoms to Single-Wall NanoTubes (SWNT), Multi-Wall NanoTubes (MWNT), Exfoliated Graphite (EG), and silica as templates for producing nanostructures of the manganese acetate cluster Mn12 (Mn12[CH3(COO)16(H2O)4O12].(2)CH3COOH.4H2O). Mn12 exhibits magnetic properties because of the molecular arrangement within the cluster and exhibits no exchange couplings between the individual clusters. Data from scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), and laser diffraction are discussed in terms of research that can expand the use of diatoms and other materials as templates for nanostructures.     

The enhanced microwave absorption property of CoFe(2)O(4) nanoparticles coated with a Co(3)Fe(7)-Co nanoshell by thermal reduction

CoFe(2)O(4) nanoparticles were fabricated by a sol-gel method and then were coated with Co(3)Fe(7)-Co by means of a simple reduction process at different temperatures under 2% H(2) with the protection of argon to generate the dielectric-core/metallic-shell structure. The optimum reflection loss (RL) calculated from permittivity and permeability of the 80 wt% CoFe(2)O(4)/Co(3)Fe(7)-Co and 20 wt% epoxy resin composites reached - 34.4 dB, which was much lower than that of unreduced CoFe(2)O(4) and epoxy resin composites, at 2.4 GHz with a matching thickness of 4.0 mm. Moreover the RL exceeding - 10 dB in the maximum frequency range of 2.2-16 GHz was achieved for a thickness of composites of 1.0-4.5 mm with 600?°C thermal reduction process. The improved microwave absorption properties are a consequence of a proper electromagnetic match and the enhanced magnetic loss besides its dielectric loss due to the existence of the core/shell structure in CoFe(2)O(4) composites. Thus, the reductive CoFe(2)O(4) nanoparticles have great potential for being a highly efficient microwave absorber.     

石墨烯/银纳米颗粒复合材料的制备及其对双氧水的电化学检测

以氧化石墨烯(GO)和硝酸银为原材料,聚乙烯吡咯烷酮(PVP)为还原剂和稳定剂,通过水热法制备出还原氧化石墨烯/银纳米颗粒(rGO/AgNPs)复合材料。采用透射电子显微镜(TEM)、X射线衍射(XRD)及紫外-可见分光光度计(UV-Vis)对rGO/AgNPs复合材料的形貌、组成和结构进行表征。同时,将rGO/AgNPs复合材料修饰到玻碳电极表面制备出过氧化氢(H_2O_2)电化学传感器,通过循环伏安法(CV)和计时安培响应法(i-t)对传感器进行电化学性能测试。实验结果表明:制备的rGO/AgNPs传感器具有较好的电化学性能,其对H_2O_2检测的灵敏度为340.6μA·(mmol/L)~(-1)·cm~(-2),响应时间为3s,最低检测极限为7.5μmol/L(S/N=3),线性检测范围为20~4950μmol/L(线性相关系数为R=0.9973)。