Weight Ratio Of Cu Research Articles

Corrosion protection of Cr[sbnd]Cu alloy coating on stainless steel

Chromium (Cr), Copper (Cu), and bimetallic chromium‑copper (CrCu) coatings were deposited on the stainless steel surface by the co-sputtering method. This research was carried out to investigate and compare the corrosion resistance of CrCu nano-coatings, and also the effect of increasing the weight ratio of Cu in CrCu alloy in a 3.5 % NaCl solution. The corrosion behavior and coating resistance properties were scouted using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (LSV). The surface of the layer was analyzed by scanning electron microscopy (SEM), atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDS), and field emission scanning electron microscopy (FESEM). The results of corrosion analyses showed a relation between copper wt% and corrosion resistance. All of the coatings impressively had a high protective influence in corrosive solution. The best yield was perceived in bimetallic chromium‑copper coating with 243 nm thickness. According to the results, corrosion current density is reduced from 1.34×10−5 to 6.80×10−8 A.cm−2 which shows this coating has a good protective efficiency (99.5 %) on stainless steel. Also, the charge transfer resistance was increased from 13.74 to 274.90 kΩ.cm2 which exhibited a protective efficiency of 95 % on the used stainless steel 304L.

Understanding of the synergy effect of DBD plasma discharge combined to photocatalysis in the case of Ethylbenzene removal: Interaction between plasma reactive species and catalyst

Hybrid non-thermal plasma combined with photocatalysis is an efficient technology for the degradation of volatile organic compounds (VOCs) and leads to a synergetic boosting effect of the degradation process. Herein, the degradation of ethylbenzene (EB) in a hybrid lab-scale reactor was performed. In the combined mode (plasma DBD and photocatalysis [TiO2 + UVA]), the degradation of EB was synergetically boosted, and a higher degradation efficiency was reached. In this study, the behavior of the synergetic effect was investigated whilst varying several operational conditions, including the UV light source (UVA and UVC), the TiO2 weight (7.5–22.51 g·m-²), the addition of metallic dopants to the TiO2 at different weight ratios (x%Cu-TiO2 and x%MnO2-TiO2, where x = 1, 3, 5 and 10 for the weight ratios of Cu:TiO2 and MnO2:TiO2) and the catalyst support (glass fiber tissue [GFT] and nickel foam [NF] with different thicknesses [0.3–3.3 mm]). Moreover, the oxygen content (0–100%) in the reactor atmosphere was examined. The results showed an enhancement of the synergetic effect under UVC (TiO2 + UVC + DBD), which may be a consequence of intensive ozone decomposition under UVC and the generation of reactive atomic oxygen. The improvement of the synergetic effect under 1% Cu-TiO2 and 10% MnO2-TiO2 catalysts is assumed to reflect the role of metallic species in the production of oxygen species on the TiO2 surface via the ozone depletion mechanism. Furthermore, TiO2/NF (3.3 mm) showed the highest synergetic effect, likely due to the conductive character and the 3D porous structure of NF. Finally, the rich oxygen composition had an apparent impact on the synergetic effect.

Copper nickel co-impregnation of Moroccan yellow clay as promising catalysts for the catalytic wet peroxide oxidation of caffeine

Copper and nickel were incorporated into the prepared yellow clay (YC) using one of the most widely used methods, for the preparation of heterogeneous catalysts, which is the wet impregnation method (IPM) and its application as a heterogeneous catalyst for Caffeine (CAF). Several catalysts Cooper Nickel's Catalysts (Cu–Ni) were applied to the yellow clay with different weight ratio of Cu and Ni, in order to explore the role of both metals during the catalytic oxidation process CWPO. Furthermore, the CuNi-YC catalysts, were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), Langmuir's surface area, Brunauer Emmett Teller (BET), scanning electron microscope (SEM) and inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES), so as to get a better understanding concerning the catalytic activity's behavior of CuNi-YC catalysts. The optimization of the catalytic activity's effects on the different weight ratios of Cu and Ni, temperature and H2O2 were also examined, using Box-Behnken Response Surface Methodology RSM to enhance the CAF conversion. The analysis of variances (ANOVA) demonstrates that Box-Behnken model was valid and the CAF conversion reached 86.16%, when H2O2 dosage was equal to 0.15 mol.L−1, copper impregnated (10%) and temperature value attained 60 °C. In addition, the regeneration of catalyst's cycles under the optimum conditions, indicated the higher stability up to four cycles without a considerable reduction in its conversion performance.

Pilot cooling tests conducted for high-copper converter matte ingots at Polar Division of PJSC MMC Norilsk Nickel

This paper describes the test methods that were applied to three ingots of high-copper converter matte with the weight ratio of Cu:Ni ~ 2.3 at Polar Division of PJSC MMC Norilsk Nickel to determine their cooling rate. The obtained results are also discussed. A test heat was done in the converter of the Nadezhdinski Metallurgical Plant, during which the following compositions were closely monitored: that of middlings; that of the finished matte that was discharged at 1,255–1,260 оС and poured in molds at 1,200 and 1,140 оС; and that of metallized matte that was intentionally overheated to 1,285–1,290 оС and poured at 1,200 оС. The cooling time was 82 and 93 hours (for capped ingots). The temperature was monitored with the help of six chromel-alumel thermocouples located at the level of 1,350, 850 and 350 mm from the bottom; three of them in the centre and the other three on a side. The ingots were crushed at the Nickel Plant, and a ~300 kg representative sample with the size of 3 mm was taken from each ingot for flotation tests. Spot samples were taken from the temperature monitoring areas for structural characterization. Based on experimental data, functional dependencies were derived with R2 0.99 that describe the obtained cooling curves. It is shown that due to the use of insulation cap in the structure defining temperature range of 1,150–750 оС, the cooling rate of the ingot top can be considerably decreased (approximately by three times). It is equal to 28–29 оС/h. In the vertically central part of all test ingots — i. e. ~850 mm from the bottom both in the centre and on a side, the cooling rates vary in the range of ~9–10.5 оС/h; in lower monitoring points — i. e. 350 mm from the bottom, they are equal to 24–33 оС/h. The cooling rate of the overheated matte at the top drops to 67 versus 87 оС/h for the uncapped ingot, whereas in the centre and at the bottom it almost remains the same.

A tetraphenylethylene-functionalized benzoxazine and copper(II) acetylacetonate form a high-performance polybenzoxazine

In this study, we synthesized TPE-BZ, a new tetraphenylethylene (TPE)-functionalized benzoxazine (BZ) monomer (1,1,2,2-tetrakis(3-phenyl-3,4-dihydro-2H-benzo[e] [1,3]oxazin-6-yl)ethane), through reduction of the Schiff base formed from TPE-4OH–CHO (1,1,2,2-tetra(3-formyl-4-hydroxyphenyl)ethylene) and aniline and subsequent reaction with paraformaldehyde. Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance spectroscopy, and mass spectrometry confirmed the structure of the TPE-BZ monomer. We used differential scanning calorimetry (DSC), FTIR spectroscopy, and thermogravimetric analysis (TGA) to investigate the thermal ring opening polymerization (ROP) and thermal stability of the TPE-BZ monomer after thermal treatment at various temperatures (from room temperature to 250 °C). The TGA profiles revealed that thermal treatment at 250 °C under a N2 atmosphere gave a poly(TPE-BZ) that possessed excellent thermal stability and a high char yield (435 °C, 64.3 wt%). Furthermore, water contact angle measurements of the poly(TPE-BZ) obtained at 210 °C for 2 h indicated a relatively low surface free energy (18.6 mJ m−2), presumably because of strong intramolecular hydrogen bonding between the phenolic OH groups and the N-Mannich bridge in the polybenzoxazine matrix. We also employed DSC, FTIR spectroscopy, and TGA to examine the specific interactions in TPE-BZ/Cu(acac)2 complexes. DSC analysis revealed that blending the TPE-BZ monomer with various weight ratios of Cu(acac)2 lowered the thermal curing temperature of TPE-BZ from 250 to 239 °C, accompanied by a lower curing temperature at 189 °C. Using the Kissinger method, the activation energy of the TPE-BZ/Cu(acac)2 complex (127 kJ mol−1) was lower than that of the TPE-BZ monomer (141 kJ mol−1), suggesting that Cu(acac)2 functioned as a catalyst that initiated ROP of the oxazine units, while providing a product that retained high thermal stability.

Effect of copper (II) nitrate 3H2O on the crystalline, optical and electrical properties of poly(vinyl alcohol) films

Composite films of poly (vinyl alcohol) PVA doped with various weight ratios of Cu(NO3)2.3H2O (0, 1, 5, 10 and 20) wt% have been prepared by solution casting method. Using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and Ultraviolet–Visible (Uv-Vis) spectroscopy, the synthetic composites were analyzed. The findings showed that Cu(NO3)2.3H2O interacts with the hydroxyl group present in PVA chain. The XRD analysis revealed that after adding Cu(NO3)2.3H2O, PVA crystallites were destroyed. With increasing Cu(NO3)2.3H2O ratio, the absorbance of composite samples increased. The optical band gap energy of the composite samples was calculated using Tauc’s formula and it reduced by increasing dopant concentration. The dielectric modulus and ac conductivity of the composite films have been studied. Ac conductivity was found to increase by increasing the dopant concentration up to 10 wt%. Electrical conduction is carried out using correlated barrier hopping model.

CeO2@SiO2 Core-Shell Nanostructure-Supported CuO as High-Temperature-Tolerant Catalysts for CO Oxidation.

Supported CuO-CeO2 catalysts have been extensively studied for their outstanding catalytic activity in CO oxidation. Unfortunately, they are prone to sintering and deactivation when exposed to high-temperature automotive exhausts. Herein, taking advantage of the heat-resistant SiO2 microspheres, we fabricated a series of core-shell-structured yCuO- xCeO2@SiO2 ( x is the weight ratio of CeO2-SiO2 and y is the weight ratio of Cu-(CeO2@SiO2)) composite catalysts. All the small CeO2 particles were bound to the SiO2 spheres, forming an xCeO2@SiO2 structure, on the surface of which a certain amount of CuO was well-dispersed. The 5CuO-50CeO2@SiO2 catalyst exhibited good activity, with the full conversion of CO achieved at around 130 °C, and no obvious deactivation was observed in the stability test. Importantly, the interaction between CuO and CeO2@SiO2 enhanced its durability at high temperatures. Even at 800 °C and with a space velocity of 800 000 mL·gcat-1·h-1, CO conversion could be maintained at 90%, which is prospectively applied in a real CO elimination system. The result of the temperature-programmed reduction in hydrogen demonstrated that this special core-shell-structured 5CuO-50CeO2@SiO2 catalyst improved the reduction ability of the CuO species. In situ diffuse reflectance infrared Fourier transform spectroscopy measurements further confirmed that CO molecules preferred to be adsorbed on Cu(I) species to form reactive CO-Cu(I) that enhanced the reactivity of the 5CuO-50CeO2@SiO2 catalyst.

Nature inspired ZnO/ZnS nanobranch-like composites, decorated with Cu(OH)2 clusters for enhanced visible-light photocatalytic hydrogen evolution

In this study, ZnO/ZnS hierarchical nanobranch like composite with Cu(OH)2 clusters were designed via a simple facile hydrothermal process followed by precipitation reaction. Anchoring Cu(OH)2 clusters on the ZnO/ZnS composite surface can shorten the charge migration distance, providing abundant active sites and extend the visible-light absorption. The effects of Cu(OH)2 clusters loading on the photocatalytic application were investigated. The photocatalytic activities for hydrogen production were evaluated under visible-light (λ > 400 nm) irradiation. It was found that coupling suitable weight ratio of Cu(OH)2 cluster over the ZnO/ZnS nanobranches will enhance the photocatalytic hydrogen evolution by 46.5 and 13.7 times higher than pure Zn5(CO3)2(OH)6 and ZnO/ZnS, nanobranches respectively and an apparent quantum efficiency of 11.5% at λ = 420 nm, and 14.7% under monochromatic LED light irradiation of 520 nm wavelength was achieved. This results show that construction of ZnO/ZnS nanobranches decorated with Cu(OH)2 clusters can effectively improve the charge transfer and enhance the photocatalytic hydrogen production. The as-prepared ZnO/ZnS nanobranches decorated with Cu(OH)2 clusters exhibits outstanding stability and recyclability. The mechanism for the enhanced hydrogen evolution is also discussed.

Fabrication of electrically conductive substrates using copper nanoparticles-deposited carbon black

Carbon black particles surrounded by copper nanoparticles (Cu NPs) were synthesized using electroless plating method. Palladium chloride was adsorbed onto carbon black, followed by the reduction of palladium chloride for catalyzing the reduction of Cu ions on the surface of carbon black particles. After that, carbon black particles doped by palladium catalyst were dispersed and stirred in Cu plating bath. Cu ions being reduced, Cu NPs surrounded the surface of carbon black particles (Cu@CB). The ratios of Cu to carbon black were controlled through variation of weight of Cu ions in Cu plating bath from 1:1 to 1:7. Cu@CB was applied to electrically conductive substrates with ethyl cellulose binder. Electrical properties and morphology were measured and compared with different weight ratio of Cu and carbon black. It was found that when weight ratio of Cu to carbon black was above three, resistivity of conductive substrates fabricated decreased dramatically. Lowest resistivity was 5.93 × 10−4 Ωcm, confirming the advantages of Cu@CB which has possibility of lowering weight percentage of metal in conductive substrates through simple process.

Nickel-promoted copper–silica nanocomposite catalysts for hydrogenation of levulinic acid to lactones using formic acid as a hydrogen feeder

Highly active, thermally stable nickel-promoted copper–silica nanocomposite catalysts were prepared via a deposition–precipitation method and used for hydrogenation of levulinic acid (LA) using formic acid (FA) as H2 feeder. Ni(20)Cu(60)-SiO2 (3:1 weight ratio of Cu to Ni, 80wt% metal content) showed better activity for vapor-phase formation of γ-valerolactone (GVL) from LA with FA as a hydrogen source. The catalyst selectively converts 99% of LA into 96% of GVL; the remaining 4% is angelica-lactone (AL). The effect of different concentrations of Ni promoted on Cu-silica and different LA to FA molar ratios on the catalyst activity affecting the hydrogen-free hydrogenation of LA was studied. The catalyst Ni(20)Cu(60)-SiO2 exhibited long-term stability (200h) without loss in activity. Characterization using TEM, XPS, TPR, XRD and N2O titration was performed to find the most active phase for LA hydrogenation to GVL and the reason for the long-term stability. It was found that Ni-promoted well-dispersed metallic Cu species were the most active phases in hydrogenation, and the nanocomposite nature of the catalyst helped in providing long-term stability to the active phase.

Performance of the nano-structured Cu–Ni (alloy) -CeO2 anode for solid oxide fuel cells

In this work, copper and nickel oxides (CuO–NiO) powders with various mole ratios were synthesized by the glycine nitrate process (GNP) and the Cu–Ni alloy was obtained by reducing the CuO–NiO powders at 600 °C for 0.75 h. Furthermore, Cu1−xNix (alloy) -CeO2 impregnated YSZ anodes were fabricated by the impregnation method and the optimized anode composition was evaluated. It was found that the optimized mole ratio of Cu:Ni was 5:5, while the weight ratio of Cu–Ni alloy to CeO2 was 3:1. Additionally, impregnated anode with 40 wt % loading of Cu0.5Ni0.5 (alloy)-CeO2 exhibited the best performance and the polarization resistance of such anode was only 0.097, 0.115, 0.145 and 0.212 Ω cm2 at 750, 700, 650 and 600 °C, respectively. Finally, the performance of the optimized anode in methane (CH4) was investigated and the carbon deposition is greatly suppressed compared to the Ni-based anode.

Influence of Preparation Conditions on Characteristics, Reactivity, and Operational Life of Microsized Fe/Cu Bimetallic Particles

The effect of the preparation conditions on the physicochemical characteristics, operating life, and reactivity of Fe/Cu bimetallic particles was studied significantly by using a model pollutant (p-nitrophenol), scanning electron microscopy–energy dispersive spectrometry, and X-ray diffraction spectrometry. The results suggest that the higher reactivity and longer operating life of Fe/Cu bimetallic particles were obtained under the optimal preparation conditions. Furthermore, under the optimal preparation conditions, Cu was not easily dropped from the Fe0 particle, and the weight ratio of Cu on the surface of the Fe/Cu bimetallic particles increased significantly. Moreover, their optimal theoretical Cu mass loading could be decreased from 0.89 to 0.41 g Cu/g Fe, which favors the reduction of production costs. In addition, two batch experiments with Fe/Cu bimetallic particles prepared under optimal and nonoptimal conditions were set up to comparatively investigate the improvement of operating life and reactivity of Fe/Cu particles when optimized preparation conditions were carried out. As a result, it was proven that the reactivity and operating life of Fe/Cu bimetallic particles could be improved significantly through the optimization of preparation conditions.

Effects of Cu–ZnO Content on Reaction Rate for Direct Synthesis of DME from Syngas with Bifunctional Cu–ZnO/γ-Al2O3 Catalyst

The effects of Cu–ZnO content on the performance of bifunctional Cu–ZnO/γ-Al2O3 catalysts for dimethyl ether (DME) synthesis from syngas were investigated by varying the weight ratios of Cu–ZnO/γ-Al2O3 prepared by the coprecipitation of Cu–ZnO in a slurry of γ-Al2O3. A higher rate of DME production with CO conversion of 47.6 % and DME selectivity of 61.1 % was observed with the bifunctional catalyst at an optimal weight ratio of CuO/γ-Al2O3 of two, providing a higher surface area of metallic copper and an abundance of weak acid sites. The number of acidic sites on solid-acid γ-Al2O3 is a more crucial factor to enhance DME yield, due to the faster dehydration rate of methanol to DME than that of CO hydrogenation to methanol. Although the first step of methanol synthesis on active copper sites is a rate-limiting step with a low equilibrium value, the second step of the dehydration of methanol to DME on acid sites adjusts the overall rate by enhancing the forward reaction rate of CO hydrogenation to methanol with a simultaneous formation of surplus hydrogen by a water–gas shift reaction. Therefore, the proper design of a high surface area of metallic copper with larger acid sites on the bifunctional CuO–ZnO/γ-Al2O3 catalysts at an optimal ratio, produced by adjusting the weight ratio of CuO/γ-Al2O3, is an important factor for improved catalytic performance.

Copper(I) Selenide Thin Films Deposited by a Solution-Based Method for Photovoltaic Applications

Polycrystalline Cu(2-x)Se thin films for solar cell application were deposited by a solution-based continuous flow reactor (CFR) process. In order to study the influence of reaction time on the physical, structural, and optical properties of the Cu(2-x)Se thin films, the deposition time for impinging varied from 2 min to 15 min. Based on X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-visible spectrophotometry, the optimum time to deposit the Cu(2-x)Se thin films using the CFR process was 10 min. The X-ray diffraction analysis revealed the cubic structure of the Cu(2-x)Se thin films annealed at 400 degrees C. The estimated band gap of the film was approximately 2.20 eV and its average grain size was around 150 nm with a film thickness of 1.8 microm. Energy dispersive analysis by X-ray (EDAX) showed that the atomic weight ratio of Cu to Se in the Cu(2-x)Se film deposited for 10 min was 1.8:1, i.e., x = 0.2. The chemical binding information of the Cu(2-x)Se thin film was also studied using X-ray photoelectron spectroscopy (XPS).

Air plasma sprayed Cu–Co–GDC anode coatings with various Co loadings

In this work, Cu–Co–gadolinia doped ceria (GDC) anode coatings were fabricated by atmospheric plasma spraying (APS) of agglomerated CuO, Co3O4, and GDC feedstock powders. Screening tests were conducted to identify the effect of plasma gas composition on the coating phases, microstructure, and absolute deposition efficiency of each material. Based on screening tests, optimized plasma energy conditions were identified. Using the absolute deposition efficiency, feedstock powder mixing ratios were determined to produce anode coatings with Cu–Co weight ratios of Cu(100)–Co(0), Cu(90)–Co(10), Cu(70)–Co(30), and Cu(50)–Co(50), with 40 vol% of metal phases in the coating and 60 vol% of GDC. After reduction of the coatings, porosity and gas permeability were determined. Finally, carbon deposition behavior was examined by measuring the weight gain of the coatings after exposure to CH4 at 700 °C for 3 h. The coatings demonstrated good resistance to carbon deposition.

Bio-immobilization of Cu and Zn in recirculated bioreactor landfill

To protect the environmental quality of soil, groundwater, and surface water near the landfill site, it is necessary to make an accurate assessment of the heavy metal mobility. This study aims to present the bio-immobilization behavior of heavy metals in landfill and provide some reference suggestion for the manipulation of heavy metal pollution control after closure. Two simulated bioreactor landfill system loaded with real municipal solid waste (MSW), namely, conventional bioreactor landfill (CL) and leachate recirculated bioreactor landfill (RL), were operated. Cu and Zn, the two conventional heavy metals with the highest contents in MSW, were chosen to track the heavy metal bio-immobilization behavior in landfill. The MSW in landfill is a great threat to environment because much of the heavy metal is "hidden" in different components. The weight ratio of Cu and Zn in landfill amounts to 0.00427% and 0.00437%, respectively. The accumulated effluent masses of Cu and Zn in CL increased all along, while they still kept at a stable level after day105 in RL. The microbes like sulfate-reducing bacteria mediate the behavior of Cu and Zn in bioreactor landfill system. Cu and Zn can be bio-immobilized in bioreactor landfill system with leachate recirculation like RL.

The effect of ZnO in methanol synthesis catalysts on Cu dispersion and the specific activity

The effect of ZnO in Cu/ZnO catalysts prepared by the coprecipitation method has been studied using measurements of the surface area of Cu, the specific activity for the methanol synthesis by hydrogenation of CO2, and XRD. Although the Cu surface area increases with increasing ZnO content (0–50 wt%) as is generally known, the specific activity of the Cu/ZnO catalysts with various weight ratios of Cu:ZnO is greater than that of a ZnO-free Cu catalyst. These facts clearly indicate that the role of ZnO in Cu/ZnO catalysts can be ascribed to both increases in the Cu dispersion and the specific activity. The XRD results indicate the formation of a Cu–Zn alloy in the Cu particles of the Cu/ZnO catalysts, leading to the increase in specific activity. It is thus considered that the Cu–Zn surface alloy or a Cu–Zn site is the active site for methanol synthesis in addition to metallic copper atoms that catalyze several hydrogenation steps during the methanol synthesis. Furthermore, the advantage of the coprecipitation method through a precursor of aurichalcite is ascribed to both improvements in the Cu surface area and the specific activity.

Metal hydride electrodes with lamellar-type network structure

New types of metal hydride electrodes with three dimensional networks of conducting metal powder have been developed. Utilization efficiency of the alloy was successfully improved because of elimination of the usual non-conductive polymeric binder and also the material cost could be reduced because it was not necessary to use an expensively formed nickel substrate or an expensive surface coating process. The new electrodes are composed of hydrogen storage alloy and newly developed flake-type copper and/or nickel powder formed into a laminated network structure in the electrode, thus providing better binding ability and better electrode conductivity than a conventional dendritic powder. The mixture, in the weight ratio of Cu(Ni)/alloy=0.2, was press-bound on a nickel mesh current collector. The effect of flake powder was more pronounced for the Ti–Zr based AB 2 type alloy (less conductive surface) than the rare earth based AB 5 type alloy.