Green sonochemical synthesis of cupric and cuprous oxides nanoparticles and their optical properties

Nanoparticles of cupric oxide (CuO) and cuprous oxide (Cu₂O) with various morphologies were synthesized by a green sonochemical process without any surfactants and templates. The Cu₂O nanoparticles with the truncated cubic, cubic octahedral and octahedral morphologies were prepared via the deoxidation of the CuO nanoparticles. The Cu₂O and CuO samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet visible absorption spectroscopy (UV–vis). The experimental results indicate that the molar ratio of sodium hydroxide to copper sulfate affects the morphology and size of the CuO and Cu₂O nanoparticles produced by the sonication. The band gap energy of CuO nanoparticles was 1.45–1.75 eV, the morphology had a great effect on the optical properties of CuO. The Cu₂O nanoparticles had broad emission peaks at the visible region, and the band gap energy was estimated to be 1.95–2.09 eV. The growth mechanisms of the CuO and Cu₂O nanoparticles are discussed.     

The anodic formation and cathodic reduction of cuprous oxide films on copper in sodium hydroxide solutions

The potentiodynamic response of the Cu/alkaline solution interface in the potential range where Cu₂O is formed and reduced has been investigated using a broad range of experimental conditions, including different electrode treatments. The reproducibility of the results is also critically considered. The cathodic reaction revealed that at least three different Cu(I) species are formed during the Cu₂O formation. One of them has been attributed to a soluble Cu(I) species. One out of the two remaining Cu(I) surface species undergoes potentiostatic ageing effects. The results are discussed in terms of previously proposed reaction mechanisms related to the Cu₂O formation and reduction.     

Preparation and shape evolution of cuprous oxide in the solution phases of copper (II) dodecyl sulfate

In this paper, the functionalized surfactant of copper dodecyl sulfate [Cu(DS)₂] was used both as the metal ion source and as the modifier to investigate the preparation and shape evolution of cuprous oxide (Cu₂O). The increase of Cu(DS)₂ concentration from 0.27 to 6.82 mM caused the morphological change of Cu₂O crystals from the truncated cubic to the cuboctahedral, then to the coexistence of the cubic and the truncated octahedral, and finally to the truncated octahedrons. As an experimental control, the inorganic salt of copper (II) chloride was also used as the metal ion source to conduct the precipitation of Cu₂O. These results indicate that the special adsorption of organic counterions (i.e., dodecyl sulfate ions) exerted a great influence on the shape control of Cu₂O crystals, especially at a relatively low concentration. Meanwhile, the d-glucose concentration and the incubation time of crystals were also considered. In conclusion, the competitive adsorption of surfactant ions and d-glucose molecules onto crystalline faces, as well as the aging time, accounted jointly for the shape control of Cu₂O crystals.     

氧化亚铜纳米棒的合成与表征

利用溶剂热法,以五水硫酸铜和氢氧化钠为原料,乙醇为还原剂,在乙醇与去离子水的混合溶剂中,140 ℃条件下溶剂热处理6～10 h制得了不同长径比的氧化亚铜纳米棒.利用X射线粉末衍射仪(XRD)及高分辨透射电镜(HRTEM)对合成产物进行了物相与形貌分析.检测结果显示合成的纳米棒结晶程度良好,尺寸较为均匀.在实验中还发现反应温度与溶剂中的含水量是影响乙醇还原性的主要因素.     

Preparation and near-infrared photothermal conversion property of cesium tungsten oxide nanoparticles

Cs_0.33WO₃ nanoparticles have been prepared successfully by a stirred bead milling process. By grinding micro-sized coarse powder with grinding beads of 50 μm in diameter, the mean hydrodynamic diameter of Cs_0.33WO₃ powder could be reduced to about 50 nm in 3 h, and a stable aqueous dispersion could be obtained at pH 8 via electrostatic repulsion mechanism. After grinding, the resulting Cs_0.33WO₃ nanoparticles retained the hexagonal structure and had no significant contaminants from grinding beads. Furthermore, they exhibited a strong characteristic absorption and an excellent photothermal conversion property in the near-infrared (NIR) region, owing to the free electrons or polarons. Also, the NIR absorption and photothermal conversion property became more significant with decreasing particle size or increasing particle concentration. When the concentration of Cs_0.33WO₃ nanoparticles was 0.08 wt.%, the solution temperature had a significant increase of above 30°C in 10 min under NIR irradiation (808 nm, 2.47 W/cm²). In addition, they had a photothermal conversion efficiency of about 73% and possessed excellent photothermal stability. Such an effective NIR absorption and photothermal conversion nanomaterial not only was useful in the NIR shielding, but also might find great potential in biomedical application.     

Characterization of oxide layers on copper by linear potential sweep voltammetry

The characteristics of the electrochemical reduction of copper oxide have been studied using linear potential sweep voltammetry. Copper(II) and copper(I) oxides, formed on copper electrodes during triangular potential cycling, reduced at potentials close to the reversible values for the CuO–Cu₂O and Cu₂O–Cu couples, respectively. The reduction of bulk Cu₂O and CuO deposited on carbon paste, glassy carbon and copper electrode surfaces required significant overpotentials. Both oxide species could be distinguished from the potentials of their cathodic reduction peaks. In each system studied, CuO was reduced before Cu₂O. We discuss the implications of these findings on the Pops and Hennessy galvanostic method for determining oxides formed on copper in the wire industry.     

(Zn,H)-codoped copper oxide nanoparticles via pulsed laser ablation on Cu-Zn alloy in water

ABSTRACT: Nanosized (5 to 10 nm) amorphous and crystalline nanocondensates, i.e., metallic α-phase of Zn-Cu alloy in face-centered cubic structure and (Zn,H)-codoped cuprite (Cu2O) with high-pressure-favored close-packed sublattice, were formed by pulsed laser ablation on bulk Cu65Zn35 in water and characterized by X-ray/electron diffractions and optical spectroscopy. The as-fabricated hybrid nanocondensates are darkish and showed photoluminescence in the whole visible region. Further dwelling of such nanocondensates in water caused progressive formation of a rice-like assembly of (Zn,H)-codoped tenorite (CuO) nanoparticles with (001), (100), and {111} preferred orientations, (111) tilt boundary, yellowish color, and minimum bandgap narrowing down to ca. 2.7 eV for potential photocatalytic applications.     

Effect of KOH on the continuous synthesis of cobalt oxide and manganese oxide nanoparticles in supercritical water

The effects of KOH on the supercritical hydrothermal synthesis of cobalt oxide and manganese oxide particles are investigated using a continuous-flow reactor. Significant changes in morphology, particle size, and oxidation state are observed by adding KOH. The spinel Co₃O₄ phase is transformed to a rocksalt CoO phase and the pyrolusite MnO₂ phase is transformed to a hausmannite Mn₃O₄ phase in the presence of 0.5 M KOH. The average particle size of the metal oxides decreased with an addition of KOH. The OH⁻ ions of KOH may act as a reducing agent as well as a supersaturation enhancing agent under supercritical water conditions.     

Electrochemical production of cuprous oxide using the anode-support system

The preferred process for the production of cuprous oxide powder is by the anodic dissolution of copper in an alkaline solution of sodium chloride. The purpose of the present investigation was to develop a cuprous oxide process suitable for use on an industrial scale usiing the anode-support system, i.e. an anode comprising a titanium mesh basket loaded with small pieces of high-grade copper scrap. Laboratory investigations with this type of anode together with a titanium mesh cathode were conducted using cells having capacities up to 400 dm³. The recommended operating conditions based on 120 h runs using the 400 dm³ cell are as follows: NaCl: 250 g dm^–3; c.d.: 6 A dm^–2; CI: 0.37 A dm^–3; temperature: 80°C; pH 10. Of particular importance, especially as regards the quality of the product and cell scale-up, is the relationship between the current and the volume of the electrolyte, denoted as Cl and expressed as A dm^–3. The use of anode and cathode diaphragms of polypropylene obviated the need for additives to counteract copper redox reactions in the cell. The power yield was 0.8–0.9 kWh kg^–1. The product was well within ASTM specification D912-65 for Cu₂O for use in antifouling paints.     

氧化亚铜在太阳能电池、光催化领域的研究进展

作为半导体光电功能材料,Cu2O薄膜和纳米材料由于具有独特的能带结构和优异的性能,在电子信息、能源、环境保护等领域具有重要的应用前景。介绍了Cu2O薄膜与纳米材料的制备方法及其在太阳能电池和光催化领域的应用。分析了目前存在的问题,并提出今后研究的对策。     

氧化亚铜微米晶的水热合成与生长机理

氧化亚铜是一种重要的P型半导体材料，目前因其独特的可见光催化性能在科研领域引起了广泛的重视。以CuSO4·5H2O为铜源，以α—D-葡萄糖为还原剂，并利用水热还原反应合成出了不同形貌的Cu2O微米晶。利用X射线粉末衍射分析（XRD）、透射电子显微镜（TEM）对合成的样品进行了形貌与结构的表征与分析。结果表明所合成的晶粒尺寸均匀且分散性好。讨论了不同条件下的晶粒生长机理，运用扩散机制与聚集机制解释了不同形貌的成因。     

Application of polarisation curves to the study of the electrochemical process for producing cuprous oxide

Polarisation curves are useful for establishing the optimum experimental conditions for producing electrolytic cuprous oxide. They provide a reasonable means of determining the influence of each variable on cuprous oxide formation at an electrode surface. In this work, a sodium chloride solution was electrolysed, and sodium hydroxide and sodium nitrate (in several concentrations) were added in successive stages to determine the behaviour of the resultant systems. Finally, the effect of the presence of cuprous oxide on the cathodic behaviour of the electrode was studied. The working electrode was of copper and the experiments were conducted at different temperatures. The polarisation curves were obtained without agitating the liquid and with aerated and deaerated solutions. The passage of nitrogen during 30 min removed oxygen from the electrolyte.     

Electrochemical production of cuprous oxide and metallic nickel in a two-compartment cell

The purpose of the present investigation was to develop an electrochemical process to obtain simultaneously cuprous oxide powder and metallic nickel in a two-compartment cell. Nafion® 901 bimembrane (Dupont, USA) was employed to separate the compartments to avoid the diffusion of nickel ions from the catholyte to the anolyte. A continuous addition of sodium hydroxide solution to the anodic compartment was necessary to form in situ the cuprous oxide by chemical reaction with the cuprous chlorocomplexes generated at the anode. As an anode system, a titanium basket filled with copper scrap wire was utilized. The anodic operating conditions were: NaCl 250 g dm^?3, pH 10, 80°C, c.d. 6 A dm^?2 and current concentration 0.4 A dm^?3, The cathodic parameters were: Ni²ⁱ 74 g dm^?3, H₃B0₃30 g dm^?3, sodium lauryl sulphate 0.5 g dm^?3, coumarin 0.15 g dm^?3, pH2, 50°C, c.d. 6 A dm^?2 Good quality red-violet cuprous oxide powder, meeting ASTM specifications D912-65 to be used in antifouling paints and metallic nickel (> 99.96% Ni) was obtained.     

甘油铜分光光度法测定生物柴油转化率的研究

采用甘油铜分光光度法测定了碱催化酯交换法制备生物柴油过程中的甘油含量,确立了最佳测定条件:取3.5 mL 0.05 g/mL NaOH与1 mL 0.05 g/mL CuSO4摇匀,加入3 min离心处理后的样品,超声5 min,离心3 min,然后在波长630 nm处测定吸光度。运用高碘酸钠氧化法对分光光度法的准确度进行验证。结果表明,改进后的方法操作简单,相对误差为-0.490%。     

Mn掺杂Cu_2O微粒的制备及其光催化性能研究

以乙酸铜和乙酸锰为原料,通过超声辅助水热法制备了Mn掺杂Cu_2O微粒,并对其结构和光电性能进行了表征与分析。以次甲基蓝为目标降解物,对样品的光催化性能进行了评价。结果表明,所制备的Cu_2O呈八面体形貌,具有(111)晶面择优取向,Mn掺杂Cu_2O形貌呈凹陷八面体,与纯Cu_2O相比,Mn掺杂Cu_2O微粒的粒径减小,比表面增大,在可见光范围内吸收强度和禁带宽度均增大,光电流增强,表面电阻显著降低,光生电子-空穴的分离效率得到有效提高。光催化活性得到了显著提高,次甲基蓝的降解率可达91.6%。     

The catalytic activity and electronic property of cupric oxide semiconductor

The correlation between catalytic and electronic properties has been experimentally verified for cupric oxide semiconductor. The catalytic activity of cupric oxide for CO oxidation was measured in terms of energy of activation for CO chemisorption whereas the electronic property was measured in terms of the electrical conductivity. The semiconducting properties of cupric oxide were varied by doping with different proportions of altervalent ions such as lithium and gallium.     

Vapour phase oxidation of ethylene glycol to glyoxal on supported cupric oxide

The vapour phase oxidation of ethylene glycol to glyoxal by air was studied in a stainless steel tube reactor using cupric oxide as a catalyst on carriers such as active alumina, pumice stone, silicon carbide, ceramics and fused alumina. A catalyst containing 3 to 5% cupric oxide on pumice stone was found to be satisfactory for the process. The effects of temperature, period of reaction and concentration of ethylene glycol and oxygen on the yield and conversion to glyoxal were studied, and the most suitable conditions were determined for the process. Carbon dioxide and formaldehyde were the major by-products in the reaction. Formaldehyde was formed mainly due to the homogeneous reactions of ethylene glycol with oxygen in the void space of the reactor. The formation of glyoxal and carbon dioxide were correlated by suitable empirical rate expressions.     

氧化锌和硫化镉共复合氧化亚铜纳米线的制备及其光催化性质

以氯化铜和氢氧化钠为原料,聚乙二醇为表面活性剂,水合肼为还原剂,水为溶剂,采用简单还原法制备氧化亚铜纳米线。然后通过水热法将纳米氧化亚铜、氧化锌和硫化镉进行复合。利用SEM和XRD对制备的产品进行表征。对制备的产品进行光催化活性测试。结果表明,在以汞灯为光源,亚甲基蓝的浓度为15 mg/L时,三元复合的产品活性最高,单纯氧化亚铜纳米线活性最低。     

氧化锌和硫化镉共复合氧化亚铜纳米线的制备及其光催化性质

以氯化铜和氢氧化钠为原料,聚乙二醇为表面活性剂,水合肼为还原剂,水为溶剂,采用简单还原法制备氧化亚铜纳米线。然后通过水热法将纳米氧化亚铜、氧化锌和硫化镉进行复合。利用SEM和XRD对制备的产品进行表征。对制备的产品进行光催化活性测试。结果表明,在以汞灯为光源,亚甲基蓝的浓度为15 mg/L时,三元复合的产品活性最高,单纯氧化亚铜纳米线活性最低。