Preparation and electrocatalytic property of three-dimensional nano-dendritic platinum oxide film

Platinum oxide electrode, as an important part of hydrogen concentration monitoring sensor built in containment, needs to withstand extreme conditions such as high temperature, high humidity, and high irradiation and can still work normally even in the case of serious accidents, which puts forward higher requirements for its performance. In present study, platinum oxide film electrode was successfully prepared with three-dimensional nano-dendritic, uniform, and crack-free on platinum substrate by reactive magnetron sputtering, and the influence of different substrate temperature and sputtering atmosphere on the composition, morphology, and electrocatalytic property of the film was investigated. The results show that platinum oxide film is composed of PtO and PtO₂. As the temperature increases from room temperature (RT) to 200°C, the oxygen vacancies in the amorphous film are gradually repaired and convert to the crystalline state, which shows increasing PtO₂ ratio, increasing electrochemical active area (ECSA), and improved stability. When the temperature is rising to 400°C, the film shows decreasing oxygen vacancies, increasing average grain size. Because PtO₂ decomposes into PtO and Pt, and thus ECSA decreases, the stability and oxygen reduction activity of the films decreases gradually. At the same temperature, the crystalline film obtained in Ar/50%O₂ has higher concentration of oxygen vacancies and smaller average grain size than that obtained in O₂, resulting in larger ECSA and relatively good stability. By contrast, the platinum oxide film electrode prepared in Ar/50%O₂ and 200°C has better stability and excellent electrocatalytic activity for oxygen reduction.     

Adhesion of an aromatic thermosetting copolyester with copper foils

Copper foils have been widely used in microelectronic devices. Adequate adhesion between copper foils to various substrates, such as Si, SiO₂, polyimide, is crucial to high performance of these devices. The adhesion between a new high temperature adhesive, aromatic thermosetting copolyester (ATSP), and various copper foils, namely, zinc(Zn)‐coated copper foil, copper foil and nickel (Ni)‐coated copper foil was characterized by a 90° peel strength test. It was found that the peel strength of Zn‐coated copper foil to ATSP was 1050 N/m, which was more than three times higher than copper foil and five times that of Ni‐coated copper foil. Scanning electron microscopy (SEM), atomic force microscopy (AFM) and X‐ray photoelectron spectroscopy (XPS) studies indicated that this higher adhesion results from the stronger mechanical interlocking due to the rougher surface of Zn‐coated copper foil, and from chemical reactions at the interface which occur during the curing process of ATSP on the Zn‐coated copper surface. In contract to the adhesive failure at the ATSP/Cu and ATSP/Ni interfaces, the failure mechanism of ATSP/Zn is both cohesive and adhesive. Copyright © 2004 John Wiley & Sons, Ltd.     

Bismuth Film Electrodes for Adsorptive Stripping Voltammetric Determination of Sunset Yellow FCF in Soft Drinks

The bismuth film electrode was used to record well‐developed voltammograms of azo food coloring Sunset Yellow FCF (SY). The employed Bi(III)/HClO₄ plating solutions produced very adhesive and mechanically stable films that were applied in both stationary and flow conditions. The influence of the dimensions of the glassy carbon support, plating solution concentration and potential was discussed. The sensitivity of SWV was sufficient to obtain a linear calibration curve for low concentration levels of SY (below 0.1 mg/L; LOD=1 µg/L, linear range 4.4–87 µg/L). The measurements in a flow system were considered as a tool for the determination of relatively high concentrations (>1 mg/L; LOD=300 µg/L, linear range 300–8800 µg/L) of SY.     

Investigation of an alternative chemical agent to recover valuable metals from anode slime

Anode slime (AS) including high content of precious metals is a by-product obtained after the electro-refining stage in copper production. In this study, it is aimed to recover Cu, Au, and Ag from the AS by using 1-butyl-3-methyl-imidazolium hydrogen sulphate ([Bmim]HSO₄) ionic liquid (IL) as a green solvent. The effects of IL concentration, temperature, reaction time and pulp density on recovery of valuable metals were statistically investigated. A high copper recovery of 87.52% was obtained under optimum condition as in 60% (v/v) [Bmim]HSO₄ at 50 °C after 2 h, pulp density at 40 g/L (1/25 solid/liquid ratio). Also, a remarkable gold recovery as 97.32% has been achieved in 80% (v/v) [Bmim]HSO₄ at 95 °C after 4 h, pulp density at 40 g/L. Temperature and IL concentration were detected as the most effective parameters for copper and gold recovery from AS, respectively. Silver could not be recovered from the AS due to the lower solubility in [Bmim]HSO₄ IL media. According to experimental results, [Bmim]HSO₄ could be offered as an alternative leaching agent, instead of conventional solvents, to recover valuable metals from copper anode slime.     

Optical and electrical measurements on CO2 covered copper films

Thin polycrystalline copper films are deposited in a special UHV cell on glass substrates and are covered step by step with CO₂. The optical and electrical properties of the films are studied in-situ by means of ellipsometry and resistivity measurements. The properties of the clean films correspond to literature data. In the case of monolayer adsorption of CO₂, the changes in the ellipsometrical angles are δΔ≈+1° and δψ≈+0.1°, similar to the Cu/O and Cu/CO systems. Three-dimensional island growth leads to a drastical increase of δΔ and δψ by several orders of magnitude. The resistivity first quickly decreases and then slowly reapproaches the initial value. This marked kinetics is quantitatively interpreted on the basis of a diffusion model.     

Adhesion characteristics of aromatic thermosetting copolyester and glass fiber laminates with copper foils for improved circuit boards

Copper foils are the vital elements used in microelectronic devices. Adequate adhesion between copper foils to various substrates, such as Si, SiO₂ and polyimide, is crucial to functional electronic devices. Liquid‐crystalline polymers (LCPs) can be used as substrates for these modules as well as the adhesive to copper foils. The adhesion between aromatic thermosetting copolyester (ATSP)/fiberglass fabric (GF) laminates and copper foils was characterized by peel strength tests. It was found that ATSP/GF laminates with copper foil using ATSP oligomers as adhesive showed a highest average peel strength of 711 N · m^?1. Scanning electron microscope (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) showed an excellent bond between the composite and the copper foil interface. Failure occurred between the backside of the copper foil and the ATSP/GF laminates in the peeling test and the mechanism is discussed. Thermogravimetic analyzer (TGA) indicated a thermal stability up to 371°C for ATSP/GF composite substrate and a glass transition temperature of over 400°C as determined by peak in tan δ during Dynamic Mechanical Analysis (DMA). Copyright © 2016 John Wiley & Sons, Ltd.     

Robust perfluorosilanized copper surfaces

Polished copper (Cu) surfaces modified with 1H,1H,2H,2H‐perfluorodecyltrichlorosilane (PFTS) have been shown to be very hydrophobic and stable. Mechanically polished, oxidized, and PFTS‐reacted Cu surfaces were characterized by X‐ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy, which confirmed the presence of perfluorinated alkyl chains. For a PFTS‐modified Cu surface (PFTS/Cu), the sessile drop static contact angle of pure water at ambient temperature and high relative humidity (RH) was measured to be more than 125° and the Zisman critical surface energy to be typically less than 16 mN/m. Ellipsometry showed the thickness of the PFTS/Cu film to be typically less than 25 nm. Stability tests indicated that the PFTS/Cu film could survive in pure boiling water for one hour, boiling nitric acid (pH 1.5 or 1.8) for 30 min, sodium hydroxide solution (pH 12, 70 °C) for 30 min, and autoclave conditions (steam at 134 °C and 3 atm) for 15 min. The more commonly used self‐assembled monolayer (SAM) modifications of Cu surfaces, e.g. thiol compounds, are significantly less stable than PFTS/Cu. The extremely hydrophobic and stable PFTS/Cu could be a very good candidate for corrosion inhibition and/or heat exchangers exploiting condensation. Copyright © 2005 John Wiley & Sons, Ltd.     

不同分子量PEG的铜电镀液对电化学沉积铜行为的研究

研究了在酸性镀铜溶液中添加不同分子量的PEG对直径为50微米、深径比为1的镀层盲孔填充效果的影响.结果表明,随着PEG分子量的增加,电镀铜溶液的微孔填充力明显提高.电流密度为2 A/dm2,添加剂PEG分子量(u)超过6000时,镀液可以完全填充盲孔,镀层不出现任何空洞和缝隙.这是由于添加剂PEG能明显加强电镀铜镀液阴极极化,抑制了电镀铜的沉积.同时,PEG于镀液中的扩散系数还随其分子量的增加而降低,从而增加了SPS在微孔底部的吸附力,加速了电镀铜在微孔底部的沉积.进一步,增大PEG分子量,沉积铜膜的表面粗糙度、铜膜结晶度和电阻率均有所降低.     

Cu–Al Spinel Oxide as an Efficient Catalyst for Methanol Steam Reforming

Cu–Al spinel oxide, which contains a small portion of the CuO phase, has been successfully used in methanol steam reforming (MSR) without prereduction. The omission of prereduction not only avoids the copper sintering prior to the catalytic reaction, but also slows down the copper‐sintering rate in MSR. During this process, the CuO phase can initiate MSR at a lower temperature, and CuAl₂O₄ releases active copper gradually. The catalyst CA2.5‐900, calcined at 900 °C with n(Al)/n(Cu)=2.5, has a higher CuAl₂O₄ content, higher BET surface area, and smaller CuAl₂O₄ crystal size. Its activity first increases and then decreases during MSR. Furthermore, both fresh and regenerated CA2.5‐900 showed better catalytic performance than the commercial Cu–Zn–Al catalyst.     

Complex formation of copper(II) with chrome azurol s

The complex formation of copper(II) with chrome azurol S (CAS) was studied by spectrophotometric and potentiometric methods. In the pH range 5–7, two complexes with the composition Cu(H₂O)₂HCAS- and (Cu(H₂O)₂)₂CAS were detected; the stability constants were calculated to be log K = 4.02 ±0.05 and log K = 13.7±0.1, respectively (at 25° and ionic strength 0.1 (KCl)). A comparison is made between the copper(II)-CAS and iron(III)-CAS systems.     

Novel polydentate phosphonic acids: Protonation and stability constants of complexes with Fe(III) and Cu(II) in aqueous medium

The acido‐basic and the complexation properties of di‐, tri‐, and tetra‐phosphonic acids (H₆L1, H₈L2, and H₁₀L3) toward Fe(III) and Cu(II) were determined by potentiometric titration in aqueous media at 25.0 ± 0.1°C with constant ionic strength (0.1 M, NaClO₄). We have determined six, ten, and eight pK_a values for the di, tri, and tetra‐phosphonic acids, respectively. In acidic conditions, e.g., 0 ≤ pH ≤ 5; iron and copper presented a high affinity toward these ligands to give complex species. With the ligand H₁₀L3, [FeL3H₇], and [CuL3H₆]²⁻ were easily obtained at pH 1.8 and 2.7, respectively. We have determined ten stability constants for the H₁₀L3/Fe system and nine for the H₁₀L3/Cu one; six and four in the cases of H₈L2/Fe and H₈L2/Cu systems, respectively. Finally, five stability constants were calculated for the H₆L1/Fe system and four for the H₆L1/Cu one. We have not observed any insoluble species in these complexes in acidic medium as well as in alkaline solutions. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:51–62, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20575     

Effect of the condition of synthesis on the composition and structure of copper(II) complexes with benzimidazole

The composition and structure of copper(II) benzimidazole complexes obtained by the reaction of CuCl₂ with benzimidazole (BIm) were determined. At pH 4.5–5.5, depending on the reactant ratio, dimeric compounds with the composition Cu(BIm)₄Cl₂ · 2H₂O and Cu(BIm)₂Cl₂ · H₂O are formed. They are converted to monomers at about 200°C. At pH > 8, irrespective of the reactant ratio, the polymer (Cu(OH)L)n is formed. The complexation of copper(II) with benzimidazole in water and aqueous dioxane was studied by potentiometry, and the stability constants of the complex compounds and their dependence on the solvent composition were determined.     

Modeling cellobiose hydrolysis with integrated kinetic models

The enzyme cellobiase Novozym 188, which is used for improving hydrolysis of bagasse with cellulase, was characterized in its commercial available form and integrated kinetic models were applied to the hydrolysis of cellobiose. The specific activity of this enzyme was determined for pH values from 3.0–7.0, and temperatures from 40–75°C, with cellobiose at 2 g/L. Thermal stability was measured at pH 4.8 and temperatures from 40–70°C. Substrate inhibition was studied at the same pH, 50°C, and cellobiose concentrations from 0.4–20 g/L. Product inhibition was determined at 50°C, pH 4.8, cellobiose concentrations of 2 and 20 g/L, and initial glucose concentration nearly zero or 1.8 g/L. The enzyme has shown the greatest specific activity, 17.8 U/mg, at pH 4.5 and 65°C. Thermal activation of the enzyme followed Arrhenius equation with the Energy of Activation being equal to 11 kcal/mol for pH values 4 and 5. Thermal deactivation was adequately modeled by the exponential decay model with Energy of Deactivation giving 81.6 kcal/mol. Kinetics parameters for substrate uncompetitive inhibition were: Km=2.42 mM, V _max=16.31 U/mg, Ks=54.2 mM. Substrate inhibition was clearly observed above 10 mM cellobiose. Product inhibition at the concentration studied has usually doubled the time necessary to reach the same conversion at the lower temperature tested.     

HPLC analysis of metal chelating agents in micronutrients

The separation and quantitative determination of organic chelating agents such as DTPA, EDDHA, EDDHMA, EDTA and HEDTA as their copper chelates using HPLC and UV detection is described. Analysis is performed on a Spherogel^TM TSK column. The eluent consists of methanol/water (50: 50, v/v) and 0.25 mmol/L Cu(NO₃)₂. The pH value, the composition of the eluent, the temperature, the sample concentration, the flow rate of the eluent and the influence of the detection wavelength were optimized. The linearity of the UV detector was in the range of 0.5 mmol/L to 2.5 mmol/L.     

微量稀土对超导稳定化基体铜材的性能和组织的影响

研究了微量稀土元素对铜的机械性能、导电性和组织的影响，在铜中加入微量钇、钕、镝、铒和富铈混合稀土后，使铜的抗拉强度有所提高，并保持良好的塑性和导电性。     

The influence of polysulfones of various structures on the properties of adhesive materials

A study of a samples of polyarylsulfones and polyarylsulfidesulfones with a glass-transition point of 210–245°C as received and in the formulations of adhesive compositions has been conducted. It has been shown that the developed adhesive compositions containing polyarylsulfones are capable of forming a film and provide high strength indices of adhesive joints in shear of 23–29 MPa within a temperature range from 20 to 150°C.     

Co60 γ-radiation-induced copolymerization of ethylene and carbon monoxide

The γ-radiation-induced free-radical copolymerization of ethylene and CO has been investigated over a wide range of pressure, initial gas composition, radiation intensity, and temperature. At 20°C., concentrations of CO up to 1% retard the polymerization of ethylene. Above this concentration the rate reaches a maximum between 27.5 and 39.2% CO and then decreases. The copolymer composition increases only from 40 to 50% CO when the gas mixture is varied from 5 to 90% CO. A relatively constant reactivity ratio is obtained at 20°C., indicating that CO adds 23.6 times as fast as an ethylene monomer to an ethylene free-radical chain end. For a 50% CO gas mixture, the above value of 23.6 and the copolymerization rate decrease with increasing temperature to 200°C. The kinetic data indicate a temperature-dependent depropagation reaction. Infrared examination of copolymers indicates a polyketone structure containing ? CH₂? CH₂? and ? CO? units. The crystalline melting point increases rapidly from 111 to 242°C., as the CO concentration in the copolymer increases from 27 to 50%. Molecular weight of copolymer formed at 20°C. increased with increasing CO, indicating M?_n values >20,000. Increasing reaction temperature results in decreasing molecular weight. Onset of decomposition for a 50% CO copolymer was measured at ≈250°C.     

Thermal properties of pure and doped (polyvinyl-alcohol) PVA

Films ≈350 μm of poly(vinyl-alcohol) composites, containing copper (Cu), aluminium (Al) and iron (Fe), metallic powder very fine, were prepared by a casting method. Thermal conductivity, phonon velocity, mean free path and specific heat were studied. The pure sample of PVA has a lower values of thermal conductivity than that which are doped with metals. For all samples the thermal conductivityK increases up to a certain temperatureT _gg (120–160°C) and then decreases with temperature. The specific heat increase with temperature up to ≈120°C and above 120°C is nearly independent on temperature. The pure sample of PVA has small values of mean free path (L)≈0.2 Å at room temperature, but for PVA⁺ metalsL≈2.0 Å. The phonon velocity of pure PVA is larger than that of PVA containing metals.     

Preparation and characterization of CuAlO2 transparent thin films prepared by chemical solution deposition method

CuAlO₂ thin films were prepared on quartz glass and sapphire substrates by chemical solution deposition method using copper acetate monohydrate, aluminum nitrate nonahydrate and 2-methoxyethanol as starting precursor and solvent. The effects of annealing temperature on the structural, morphological, electrical and optical properties have been studied. Via the optimized annealing treatment condition, CuAlO₂ film annealed at 850 °C in nitrogen flow of 400sccm under atmosphere pressure exhibits the best performance with the lowest room temperature resistivity of 3.6 × 10² Ω cm and the highest optical transmission in the visible region (>70% at around 600 nm wavelength). CuAl₂O₄ and CuO phases, not CuAlO₂ phase are obtained when annealing temperature is lower than 850 °C. However, a further increase of annealing temperature weakens the crystallization quality and deteriorates the surface morphology of CuAlO₂ films as the annealing temperature exceeds 850 °C, leading to an increase in the resistivity and a decrease of the optical transmission in the visible region of CuAlO₂ films.     

Influence of bath temperatures on the wettability of copper films surface prepared by electroless plating method on beech wood

Copper films were coated on beech wood substrates by electroless plating method. The influence of bath temperature on the copper films properties was studied by varying the bath temperatures 25, 35, 45 and 55 °C. Scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS), X‐ray diffraction (XRD) pattern, X‐ray photoelectron spectroscopy (XPS), micro Raman spectroscopy and contact angle measurements were used to both characterize the physical and chemical copper films properties and understand the influence of bath temperature on the wettability of copper surface. In our studies, we have found that the gained copper mass significantly increased at 55 °C. The crystalline nature of the coated copper was confirmed by XRD. The presence of Cu₂O and CuO was observed by XPS and micro Raman techniques, which confirms the oxidization of the coated copper surface. Also these characterization techniques have shown the big influence of bath temperature on the morphology, grain size, chemical composition and the film thickness of the coated copper. The wettability was highly influenced by increasing CuO on the coated copper, which is increased by the bath temperature. The contact angle measurements have demonstrated the influence of C―O, O―C?O and CuO components of the surface on the wettability of the samples. Copyright © 2016 John Wiley & Sons, Ltd.