纳米氧化铜制备方法的研究进展

氧化铜(CuO)是二元过渡金属氧化物,其纳米结构单元有序自组装的复杂几何结构研究是近年来材料研究的热点。CuO纳米材料的多种创新研究主要是针对其制备方法,迄今为止已开发了一系列的制备方法,各种方法制备出不同结构的CuO纳米材料以适用于多方面的应用需求。本文分别对纳米氧化铜的固相合成法、液相合成法、电化学合成法、溶剂燃烧合成法以及配位沉积法这五种制备方法的研究进展做了分析总结和概述。     

水/AOT/环己烷微乳液体系制备纳米CuO颗粒及其性质表征

纳米CuO是一种具有小尺寸效应、表面与界面效应、量子尺寸效应以及宏观量子隧道效应的纳米材料，广泛运用于催化、医药、抗菌及传感器方面。微乳法作为制备纳米CuO的有效的方法之一，能够制备出稳定性高、单分散性好、粒径小的纳米CuO颗粒。采用X射线衍射仪研究了纳米CuO的组成，采用扫描电镜研究了纳米CuO的尺寸和形貌，采用电化学工作站研究了纳米CuO的电化学性质。实验结果表明：所制备样品即为纳米CuO。纳米CuO的尺寸随着水油摩尔比的增加而逐步增大，但是纳米CuO的粒径分布越不均匀，说明它的单分散性并不是很好。纳米CuO的析氢电催化性能比20%Pt/C差。     

氧化铜纳米粒子的制备与表征

纳米材料具有诸多优良特性,使其具有物理性质与常规块体材料不同,被誉为本世纪最有前途的材料。纳米氧化铜具有低熔融温度、低分解温度和高热释放已经成为可用于亚稳态含能复合材料中的比较理想的氧化剂材料。以PEG为模板,用CuCl2·2H2O和NaOH为原料,通过溶液反应制备CuO纳米粒子。分别讨论了反应物配比、PEG的分子量、PEG用量对产物形貌的影响,以得到制备CuO纳米粒子的最佳实验条件。     

纳米硫酸钙制备及应用研究进展

纳米硫酸钙因其特有的物理化学性质和力学性能在医疗、建材、橡胶材料、阻燃材料、复合材料等领域有着较为广泛的应用前景。本文介绍了近些年来国内纳米硫酸钙材料的制备方法,主要介绍了微乳液法制备硫酸钙纳米材料（纳米管／纳米粒／纳米棒）,并对纳米硫酸钙的研究现状和发展趋势进行了概述。     

氧化铈形貌对甲醇水蒸气重整制氢CuO/CeO2催化剂性能的影响

采用简单的改变焙烧气氛的方法改变水热法合成的CeO2纳米材料的形貌,得到的CeO2纳米材料再通过浸渍法制备CuO/CeO2催化剂,并将其应用于甲醇水蒸汽重整制氢反应。采用SEM、XRD、BET、H2-TPR、N2O滴定和XPS等对催化材料进行了表征,着重探讨了氧化铈形貌对催化剂结构、性质和性能的影响。结果表明,纳米棒状结构的CeO2负载CuO后得到的CuO/CeO2催化剂性能最佳,这主要是因为纳米棒状结构的CeO2与CuO的相互作用较强,表面存在较多的晶格缺陷和氧空穴,进而使得CuO/CeO2催化剂表相Cu含量增加,Cu物种的还原温度较低,催化活性较好。当反应温度为260 °C、水醇物质的量比为1.2、甲醇气体空速为800 h-1时,甲醇转化率可达100%,重整气中CO摩尔含量为0.16%。     

水热法制备纳米分散颗粒和晶须材料进展

纳米分散颗粒和一维晶须材料性能优越、用途广泛,是近年研究热点。液相法尤其是水热法因具有过程简单和能耗低等特点而被广泛用于制备纳米材料。首先介绍了近年来水热技术在纳米分散颗粒制备中的进展,包括超临界水热法、连续水热法以及水热改性法,并分析了其实现纳米颗粒粒径及分散性控制的原理。然后介绍了两种水热制备晶须材料的新思路,包括水热重结晶法和离子诱导-结构重整法,阐述了其实现晶须定向生长的机制。     

水热法制备纳米分散颗粒和晶须材料进展

纳米分散颗粒和一维晶须材料性能优越、用途广泛,是近年研究热点。液相法尤其是水热法因具有过程简单和能耗低等特点而被广泛用于制备纳米材料。首先介绍了近年来水热技术在纳米分散颗粒制备中的进展,包括超临界水热法、连续水热法以及水热改性法,并分析了其实现纳米颗粒粒径及分散性控制的原理。然后介绍了两种水热制备晶须材料的新思路,包括水热重结晶法和离子诱导-结构重整法,阐述了其实现晶须定向生长的机制。     

纳米铝/氧化铜复合材料的制备及热性能

以聚乙二醇(PEG)为模板制备了纳米氧化铜。以一种高分子材料为包覆材料自组装制备了纳米铝/氧化铜(Al/CuO)复合材料。采用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、能谱仪(EDS)、X射线衍射(XRD)等对材料的结构形貌进行了表征。利用热重分析法(TG)和差示扫描量热法(DSC)对比研究了自组装法(含包覆材料)与超声共混法(不含包覆材料)制得样品的热性能。研究了不同Al与CuO摩尔比下Al/CuO复合材料的放热量。结果表明,纳米铝与CuO发生铝热反应的放热峰约为576.4℃,放热量达1 093J/g。含有包覆材料的复合材料比不含包覆材料的复合材料具有更大的放热量。在纳米铝与CuO摩尔比为1.0∶1.2时铝热反应放热量最大,可达1 093J/g。     

纳米ZnO合成方法的研究现状

Zn O作为优良的半导体材料,其纳米材料(如纳米线、纳米棒等)在光、电、磁等方面因具有独特的性能而被广泛的应用于各个领域,因此,纳米Zn O的制备在近些年得到充分的发展,主要的制备方法分为固相法、液相法和气相法三大类。就气相法和液相法中常用的几种方法进行研究进展分析,指出每类方法的优势和存在问题,并对纳米Zn O制备技术的发展趋势进行展望。     

纳米材料对醇酸树脂涂料的改性

采用均匀沉淀法等方法制备了纳米晶须ZnO、纳米ZnO、纳米Ag、纳米TiO2、纳米SiO2等材料，并采用。一射线衍射法(XRD）、双气路氮气吸附法、扫描电子显微镜(SEM)等方法测定了所制备的纳米材料的一些物化性能指标。同时还考察了它们对醇酸树脂涂料性能的影响。结果表明纳米材料能提高醇酸树脂涂料的抗菌性能和耐酸耐碱性能。     

Constructing Morphologically Tunable Copper Oxide-Based Nanomaterials on Cu Wire with/without the Deposition of Manganese Oxide as Bifunctional Materials for Glucose Sensing and Supercapacitors

Morphologically tunable copper oxide-based nanomaterials on Cu wire have been synthesized through a one-step alkali-assisted surface oxidation process for non-enzymatic glucose sensing. Subsequently, copper oxide-based nanomaterials on Cu wire as a supporting matrix to deposit manganese oxide for the construction of heterostructured Mn-Cu bimetallic oxide architectures through spontaneous redox reaction in the KMnO₄ solution for supercapacitors. Field emission scanning electron microscopy (FESEM), field emission transmission electron microscopy (FETEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) confirmed that morphological and phase transformation from Cu(OH)₂ to CuO occurred in copper oxide-based nanomaterials on Cu wire with different degrees of growth reaction. In non-enzymatic glucose sensing, morphologically tunable copper oxide-based nanomaterials owned the high tunability of electrocatalytically active sites and intrinsic catalytic activity to meet efficient glucose electrooxidation for obtaining promoted non-enzymatic glucose sensing performances (sensitivity of 2331 μA mM⁻¹ cm⁻² and the limit of detection of 0.02 mM). In the supercapacitor, heterostructured Mn–Cu bimetallic oxide-based nanomaterials delivered abundant redox-active sites and continuous conductive network to optimize the synergistic effect of Mn and Cu redox species for boosting the pseudo-capacitance performance (areal capacitance value of 79.4 mF cm⁻² at 0.2 mA cm⁻² current density and capacitance retention of 74.9% after 1000 cycles). It concluded that morphologically tunable copper oxide-based nanomaterials on Cu wire with/without deposition of manganese oxide could be good candidates for the future design of synergistic multifunctional materials in electrochemical techniques.     

In-situ study of reduction of copper catalysts

Isothermal hydrogen interaction with unsupported CuO and 15%CuO/ZnO at about 419–427 K has been followed by in-situ X-ray diffraction as monoclinic CuO is replaced by zero-valent Cu° without direct evidence of formation of intermediate Cu₂O. Surprisingly, less than half of the copper phases within such samples is X-ray detectable. X-ray analysis indicates that reduction of crystalline CuO in CuO/ZnO catalysts may not be retarded by ZnO, but TPR-TGA suggests that reduction of more amorphous CuO may be so retarded.     

Characterization of copper oxidation by linear potential sweep voltammetry and UV-Visible-NIR diffuse reflectance spectroscopy

The aim of this study was to characterize the compounds grown on copper during oxidation at low temperature (T<573 K) in air by electrochemical and optical methods. The following oxides have been characterized: a precursor Cu _x O of mixed valency character, a non stoichiometric cuprous oxide, CuO and its precursor. The mechanism of reduction has been established for layers containing CuO and a non stoichiometric copper(I) oxide. CuO is reduced before cuprous oxide. In complicated cases, it is impossible to draw conclusions from the characteristics of the electrochemical reduction (the first step of CuO reduction and the reduction of Cu(I) species specific of the non-stoichiometry are observed at the same potential). Nevertheless, the association of a non-destructive technique such as diffuse reflectance spectroscopy and electrochemical methods allows identification of the different species present in corrosion layers on copper surfaces.     

Biosynthesis of copper oxide nanoparticles using biomass,peel, and extract polysaccharides of Solanum Tuberosum for ultrasound‐assisted adsorption of azo direct red 80 contaminants

Bio-fabrication of nanomaterials using plant polysaccharides has recently attracted much scientific attention due to its low cost and simple operation. The green synthesis of copper oxide nanoparticles as adsorbent is performed for the removal of azo direct red 80 contaminants from aqueous solution with adsorption and ultrasonic-assisted adsorption processes. The biomass, peel, and extract polysaccharides of Solanum Tuberosum were applied as eco-friendly stabilizing agents to synthesize nanoparticles. The CuO nanoparticles were characterized using FESEM, XRD, BET, and antibacterial activity tests. The CuO nanoparticles biosynthesized from peel extract have better structural properties as compared to the nanoparticles prepared from biomass and extract of Solanum Tuberosum. The result showed that the average crystallite size of the CuO nanoparticles was about 25 nm with a specific surface area of 16.35 m²/g. The adsorption capacities of 13.09 and 14.07 mg/g were obtained for dye removal with the adsorption and ultrasonic-assisted adsorption processes. Adsorption process followed the pseudo-second-order kinetic model and the contribution of intra-particle diffusion was also observed. The adsorption potential of the nanoparticles in adsorption and ultrasonic-assisted adsorption processes was assessed for binary dye solution with synergetic effect. The CuO nanoparticle has shown its high regeneration ability even after 4 consecutive cycles of regeneration-reuse.     

Preparation and thermal conductivity of CuO nanofluid via a wet chemical method

In this article, a wet chemical method was developed to prepare stable CuO nanofluids. The influences of synthesis parameters, such as kinds and amounts of copper salts, reaction time, were studied. The thermal conductivities of CuO nanofluids were also investigated. The results showed that different copper salts resulted in different particle morphology. The concentration of copper acetate and reaction time affected the size and shape of clusters of primary nanoparticles. Nanofluids with different microstructures could be obtained by changing the synthesis parameters. The thermal conductivities of CuO nanofluids increased with the increase of particle loading.     

Electrical Insulating Properties of Porcelain Enamels on Copper

The electrical properties of copper oxide-bearing porcelain enamels fired on sheet platinum and of the clear base porcelain enamel fired on sheet copper were measured. The dielectric constant, dissipation factor, and resistivity of the coatings were determined from room temperature to 700°F., and at frequencies varying from 0.1 to 100 kc. per second. The effect of firing time, firing temperature, and coating thickness on the copper ion content resulting in the coatings fired on copper was investigated. The copper ion concentration of the porcelain enamels fired on cop per was determined by X-ray fluorescence analysis. Electrical measurements of coatings fired on platinum and on copper were correlated with the copper ion concentration of the coating. At concentrations in the coating below 5% CuO, some marked changes occurred in the electrical characteristics of the coatings as a function of CuO content. These changes were even more accentuated at elevated temperatures. At concentrations varying from 5% CuO to the saturation point of CuO in the coating (about 20% CuO for coatings fired at 1600°F.), the electrical properties of these coatings at room temperature were nearly unchanged throughout this range, whereas at elevated temperatures the general effect was that of a decrease in dielectric constant and dissipation factor as the CuO content was increased.     

Synthesis and Application of Stable Copper Oxide Nanoparticle Suspensions for Nanoparticulate Film Fabrication

Colloidal suspensions of copper oxide (CuO) nanoparticles were prepared by an alcothermal method, in which copper acetate was reacted with sodium hydroxide in the presence of acetic acid in ethanol at 78°C. The prepared suspension was stable for up to 1 month without stabilizers such as surfactants. Transmission electron microscopy analyses revealed that the suspension contained nanosized CuO particles of 5–10 nm size with a narrow size distribution. Nanoparticulate CuO films packed with grains smaller than 60 nm were fabricated on Si substrates by spin coating a suspension of CuO nanoparticles and subsequent heat treatment at 500°C.     

纳米CuO/ZnO去除H_2S反应条件及机理研究

以纳米CuO/ZnO作为去除H2S的活性组分,考察了反应温度、空速、氧分压等反应条件和掺铜量对纳米CuO/ZnO脱硫性能的影响,并分析了CuO对脱硫剂脱硫机理的影响。结果表明:脱硫剂TZ2(Cu:Zn物质的量比为1:18.40)有较高的脱硫性能;空速越低脱硫性能越高;反应温度由25℃升高到120℃,脱硫性能先下降后升高,120℃的脱硫性能略高于25℃;氧分压为10%时,有最佳的脱硫性能;CuO的加入增大了脱硫产物向多硫化物及单质硫的转化。     

NO TPD and H2-TPR studies for characterisation of CuMOR catalysts The role of Si/Al ratio, copper content and cocation

NO TPD, H₂-TPR and XRD have been used to characterise copper-exchanged mordenites with different Si/Al ratios, copper contents and cocations. The results showed that copper is mainly in the form of isolated Cu²⁺ ions in CuMOR catalysts with copper exchange ≤20%, whereas at higher copper exchange CuO species are also present. These results were obtained with H and Na as cocation and were achieved by changing either the catalyst Si/Al ratio or the copper content. The data also indicate that the cocation mainly affects copper location and that copper is more easily reduced in sodium form catalysts than in protonic form.

It was found that the isolated Cu²⁺ ions are the most effective species for NO adsorption and the most active species for NO SCR.