一维氧化铝基纳米材料的制备及其形成机理

采用二次阳极氧化法制备得到孔径为60 nm的氧化铝模板。将氧化铝模板放入NaOH溶液中腐蚀约4 min左右,制备得到了氧化铝纳米管、纳米线的混合物。将沉积有InSb纳米线的氧化铝模板放入NaOH溶液中进行腐蚀5～8 min后,制备得到了InSb/Al₂O₃纳米同轴电缆。在制备基础上,讨论了氧化铝纳米管、纳米线及InSb/Al₂O₃纳米同轴电缆的形成机理。     

模板法组装尼龙-66/铂同轴纳米电缆的研究

采用简单的溶液浸润多孔氧化铝模板的方法制备了PA66的纳米管,再以这种含有PA66纳米管的模板作为“二次模板”,通过电化学沉积技术,在聚合物纳米管内部沉积金属铂纳米线,制得了PA66/铂同轴纳米电缆。用SEM和TEM等测试手段对所制备的聚合物纳米管和同轴纳米电缆进行了表征。     

模板浸润法制备非极性聚合物纳米管和纳米线

以孔径为200 nm的多孔阳极氧化铝(AAO)为模板,采用聚合物溶液或熔体浸润模板的物理方法,以非极性通用聚合物为原料,首次制备了非极性聚合物纳米管、纳米线及其阵列结构。对纳米管和纳米线的形貌和结构进行了表征,结果表明对非极性聚合物而言,温度是影响一维纳米结构的主要因素,在较低温度下只能制得纳米线;较高温度下才能得到纳米管。还指出AAO膜纳米孔的高表面效应与熔体的作用能是形成聚合物一维纳米结构的主要驱动力。     

多段异质纳米线研究取得进展

最近,中科院固体物理所盂国文小组在“多段异质纳米线与纳米管组成的分支结构”研究方面取得进展。科研人员以分支形貌孔的氧化铝为模板,采用电沉积（生长纳米线）与化学气相沉积技术（生长纳米管）结合,获得了4种由纳米线／纳米管联结组成的复杂分支结构。在此基础上,他们在化学气相沉积前,用选择腐蚀技术腐蚀掉一小段纳米线．紧接着在纳米线的两端生长纳米管,从而筑了3种由纳米管／纳米线／纳米管组成的三段异质分支纳米结构。     

粗碲化铜碱浸工艺实验研究

针对铜阳极泥综合回收产生的副产物碲化铜渣含碲较高特点,研究采用碱浸工艺从粗碲化铜中分离碲,考察了氧化条件、碱浓度、浸出温度、浸出时间、液固比(mL/g)等因素对碲浸出率的影响,结果表明:粗碲化铜在碱性浸出最佳工艺条件为:浸出液碱浓度(NaOH)为15%,液固比(mL/g)为4∶1,浸出温度为85℃,浸出时间为120 min,碲的浸出率可达83%,碲可得到初步有效分离。     

碲化铋片式管的制备及性能研究

文章通过水热法先合成了碲纳米管,再以碲纳米管为前驱体通过溶剂热法,在乙二胺四乙酸二钠和强碱KOH的作用下,与氯化铋反应生成了具有异质结的碲化铋片式管,并发现若在合适的氢氧化钾浓度以及骤冷停止反应的条件下,碲化铋片式管可以断裂成单独的环状碲化铋纳米片以及较短的片式管。所得的碲化铋片式管与微米级碲化铋粉末混合后进行SPS烧结制备成块体,其热导率与经SPS烧结的微米级碲化铋粉末相比下降了约12%。     

基于置换反应制备铂基纳米管的研究进展

作为直接醇类燃料电池阳极和阴极的催化剂,Pt基纳米管的研究受到了广泛的关注。制备Pt基纳米管的方法很多,而以一维纳米线为模板并通过一维模板与铂的前驱物的置换反应制备Pt基纳米管的方法是最主要的方法,得到了广泛的应用。本文综述了利用置换反应制备Pt基纳米管的研究进展。     

多孔阵列聚合物模板及铜微/纳米线的可控制备

金属纳米线阵列材料是最具潜力的高时空分辨X射线强辐射源材料之一。采用集束热拉伸法,通过尺寸设计和参数控制,制备了包埋高度取向的聚苯乙烯微纳米线有序阵列结构的聚甲基丙烯酸甲酯复合丝,通过后续包埋、切片、溶解等处理过程,获得孔径/孔间距约为1∶1的多孔聚甲基丙烯酸甲酯模板。通过光学显微镜和扫描电镜(SEM)观察,二级模板的孔径及孔间距尺寸约十几微米,三级模板的孔径及孔间距尺寸约500 nm。利用电化学沉积技术在制备的模板上成功地生长了铜微/纳米线,铜纳米线长度超过10μm。该研究为特定尺寸要求的金属微纳米线阵列的制备提供了技术支持。     

pn型Cu2O/CdS纳米线的制备及性能

采用电沉积法,在AAO模板中成功制备出pn型Cu₂O/CdS纳米线阵列。利用扫描电子显微镜（SEM）、透射电子显微镜（TEM）和X射线衍射分析（XRD）对样品的形貌和结构进行表征,利用光照开路电位测试和光吸收光谱测试对Cu₂O/CdS纳米线的性能进行了研究。纳米线的直径约100 nm,与AAO模板孔径相同,XRD结果表明Cu₂O/CdS纳米线由立方晶系的Cu₂O和立方晶系与六方晶系混合晶系的CdS组成。Cu₂O/CdS纳米线的光响应性能增强。在Xe灯照射下Cu₂O/CdS纳米线表现出良好的光催化性能,光照7 h后,Cu₂O/CdS纳米线对罗丹明B的降解效率达到66.02%。     

高纯碲化亚铜粉体的制备

本文将5N铜粒和5N碲块按摩尔比2∶1混合,在2×10~(-3)Pa的真空条件下加热合成,制得高纯碲化亚铜。利用X射线衍射仪、扫描电镜、ICP发射光谱仪对产品的物相成分、表面形貌、杂质元素进行表征。结果表明,碲化亚铜粉体由Cu_2Te相构成,形貌为不规则颗粒,平均粒径为8.021μm,纯度较高,达99.995%。     

氧气(1)-乙酸(2)-水(3)三元系平衡溶解度的测定及关联

建立了测定气体在液体中溶解度的实验装置,该装置一次进料能够连续测定多种压力下的溶解度数据,并测定了25～80 ℃氧气在乙酸-水混合溶剂中的溶解度数据.建立了氧气在乙酸-水混合缔合溶剂中溶解度的计算模型,给出了模型参数,模型计算平均相对误差不超过±3.0%.     

Effect of Cu on Ni nanoparticles used for the generation of carbon nanotubes by catalytic cracking of methane

In this study, a simple method for the addition of Cu to unsupported nickel nanoparticles is employed to investigate the promotion effect of copper during the nickel-catalyzed decomposition of methane into carbon nanotubes. Bulk nickel and copper acetates were mixed by grinding the parent salts in a mortar, to obtain samples with selected Ni/Cu atomic ratios (NiCu_0.03, NiCu_0.07 and NiCu_0.16) that were decomposed in situ on methane streams using a thermogravimetric analyzer (TGA). Weight increase was related quantitatively to the production of carbon nanotubes by catalytic cracking of methane, and the materials were complementary characterized ex situ by electron microscopy. The results suggest that copper most likely induces the disaggregation of nickel particles during the course of the catalytic cracking, but copper by itself was not effective to improve quantitatively the production of carbon nanotubes. In spite of very low methane conversions, good quality multiwalled carbon nanotubes are obtained and characterized by HRTEM.     

Grafting of alkoxyamine end-capped (co)polymers onto multi-walled carbon nanotubes

Multi-walled carbon nanotubes (MWNTs) have been successfully modified by polystyrene, poly(?-caprolactone), and their block copolymers by addition reaction of the alkoxyamine-terminated precursors. Polymer-modified MWNTs are easily dispersed in good solvents for the grafted polymer, such as toluene and THF. This observation has been confirmed by TEM analysis. The grafting ratio of polystyrene chains at the surface of MWNTs depends on the polymer molecular weight.     

Ion-Exchange Behavior of Mercury(II) in Mixed Solvents: Separation from Zinc(ll), Cadmium(ll), Gold(lll), and Thallium(lll)

Abstract

Distribution coefficients of Zn(II), Cd(II), Au(III), Hg(II), T1(I), and Tl(III) between cation- and anion-exchangers Amberlite IR-120 and Amberlite IR-400, and aqueous solutions containing nitric or hydrochloric acid and organic solvents have been determined. The organic solvents were methanol, acetone, and tetrahydrofuran. The separation of Hg(II) from Zn(II), Cd(II), Au(III), and Tl(III) has been proposed in mixed solvents with high separation factors. Some of these separations have been actually performed using column method.     

Ionic Liquid Effect on the Reversal of Configuration for the Magnesium(II) and Copper(II) Bis(oxazoline)‐Catalysed Enantioselective Diels–Alder Reaction

Ionic liquids have been used to support a range of magnesium‐ and copper‐based bis(oxazoline) complexes for the enantioselective Diels–Alder reaction between N‐acryloyloxazolidinone and cyclopentadiene. Compared with reaction performed in dichloromethane or diethyl ether, an enhancement in ee is observed with a large increase in reaction rate. In addition, for non‐sterically hindered bis(oxazoline) ligands, that is, phenyl functionalised ligands, a reversal in configuration is found in the ionic liquid, 1‐ethyl‐3‐methylimidazolium bis[(trifluoromethanesulfonyl)imide], compared with molecular solvents. Supported ionic liquid phase catalysts have also been developed using surface‐modified silica which show good reactivity and enantioselectivity for the case of the magnesium‐based bis(oxazoline) complexes. Poor ees and conversion were observed for the analogous copper‐based systems. Some drop in ee was found on supporting the catalyst due a drop in the rate of reaction and, therefore, an increase in the contribution from the uncatalysed achiral reaction.     

The preparation of carbon nanotube (CNT)/copper composites and the effect of the number of CNT walls on their hardness,friction and wear properties

Carbon nanotubes with 2, 3, 8 and 20 walls are mixed with a copper powder (micrometer sized) and consolidated by spark plasma sintering. The microhardness of resulting composites is found to be over 50% higher than that for Cu and the friction coefficient against a steel ball is decreased by a factor of 3–4 while the wear and wear rate are reduced by a factor of 10–20. Raman maps of selected specimens outside and inside the worn surface show that double-wall carbon nanotubes remain intact. The reasons for the effect of the number of walls and carbon content are discussed.     

A chelating resin as a probe for the copper(II) distribution in grape wines

Presented hereafter is the pilot-study of the applicability of resin titration (RT) to mixed solvents in regard to the studies of metal distribution in wines – a beverage that has attracted great attention and that has been extensively studied in the recent years.The RT method of studying the distribution of species is based on the determination of the concentration of metal ions sorbed on the iminodiacetic resin Chelex 100 at different V/w (solution volume/mass of resin). The total metal ion present in the considered solution and the free metal ion are estimated from the titration curves. The method, already applied for water solutions, was tested here in mixed solvent media, at the pH around 3, with known amounts of copper(II) and ligands with different complexing properties. Satisfactory results have been obtained and commented critically.In the application of the RT method, the protonation and the exchange reactions of copper(II) with the considered sorbent were investigated in 12% ethanol, in KCl 0.1 and 1.0 M solutions, according to a well established procedure.Finally, a white grape wine (Riesling) from a winery in Oltrepò Pavese was analyzed with RTs. In the sample obtained before processing the wine, 50% of the total Cu(II) (∼18 μM) was combined with ligands with log α_M equal to 3.3; in the final product, the total Cu(II) was 4 μM, almost totally complexed. According to these findings, the ligands accountable for the copper complexation were not the major components in the wine, as they formed considerably weaker complexes.     

纳米碳管和纳米二氧化硅修饰玻碳电极示差脉冲伏安法测微量铜

本文用纳米碳管和纳米二氧化硅修饰的玻碳电极以1mol/LH2SO4为底液测定Cu^2＋,方法是先在-0．5V进行预还原120s,然后用示差脉冲伏安法进行阳极扫描,发现在-0．04V（vs．SCE）处出现铜的氧化峰,且峰电流与Cu^2＋的浓度在5．0×10^-8～1．0×10^-2mol/L范围内呈良好的线性关系,该方法的检出下限为1．0×10^--8mol/L。用标准加入法测得回收率范围为92．3％～104．2％,相对标准偏差（RSD）为3．5％。将此电极用于实际样品的测定,取得较好的结果。     

Carbon nanotubes and onions from carbon monoxide using Ni(acac)2 and Cu(acac)2 as catalyst precursors

New catalyst precursors (copper and nickel acetylacetonates) have been used successfully for the synthesis of carbon nanotubes and onion particles from carbon monoxide. Catalyst nanoparticles and carbon products were produced by metal-organic precursor vapour decomposition and catalytic disproportionation of carbon monoxide in a laminar flow reactor at temperatures between 705 and 1216 °C. Carbon nanotubes (CNTs) were formed in the presence of nickel particles at 923-1216 °C. The CNTs were single-walled, 1-3 nm in diameter and up to 90 nm long. Hollow carbon onion particles (COPs) were produced in the presence of copper particles at 1216 °C. The COPs were from 5 to 30 nm in diameter and consisted of several concentric carbon layers surrounding a hollow core. The results of computational fluid dynamics calculations to determine the temperature and velocity profiles and mixing conditions of the species in the reactor are presented. The mechanisms for the formation of both CNTs and COPs are discussed on the basis of the experimental and computational results.     

Influence of different functionalized multiwall carbon nanotubes on the mechanical properties of poly(ethylene terephthalate) fibers

Master batches with four different kinds of functionalized multiwall carbon nanotubes (MWCTs) were prepared through the mixing of MWCTs with poly(ethylene terephthalate) (PET) (0.01 : 0.99 w/w) in trifluoroacetic acid/dichloromethane mixed solvents (0.7 : 0.3 v/v) followed by the removal of the solvents in the mixture by flocculation. The results of scanning electron microscopy showed that a good dispersion of MWCTs in PET was achieved. The reinforced fibers were fabricated by the melt spinning of PET chips with small amounts of the master batch and then further postdrawing. The optimal spinning conditions for the reinforcement of fibers were a 0.6-mm spinneret hole and a 250 m/min wind-up speed. Among the four master batches, the fibers obtained from PET/master batch B made by acid-treatment had the highest enhancement of mechanical properties. For a 0.02 wt % loading of acid-treated MWCT, the breaking strength of the PET/master batch B composite fibers increased by 36.9% (from 4.45 to 6.09 cN/dtex), and the initial modulus increased by 41.2% (from 80.7 to 113.9 cN/dtex). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008