Deposition Of Cu Nanoparticles Research Articles

Silk fibroin-copper nanoparticles conglomerated polyurethane fibers incorporating calcium carbonate for enhanced fluid retention, antibacterial efficacy and promotion of cell growth

This work blended calcite crystals with polyurethane solution and fabricated into micro/nanofibers by electrospinning. Subsequently, these fibers were hydrothermally coated using silk fibroin and deposited with copper (Cu) nanoparticles (NPs). The morphology of fibers was smooth, and the diameter increased upon incorporation of CaCO3 from 1.56 ± 1.07 μm to 3.35 ± 0.8 μm. Adding SF and Cu increased the fiber diameter, and partial or complete masking of fibrous morphology occurred with higher concentrations. The contact angle declined from 105.3 ± 0.1° to 12.1 ± 0.1° in the scaffold with SF and Cu NPs, indicating hydrophilicity. The hydrothermally modified scaffolds showed multi-step decomposition temperature with improved thermal stability compared to pristine samples. The tensile strength of PU micro/nanofibers increased from 158.5 ± 0.5 MPa to 200.06 ± 0.2 MPa, and the enzymatic degradation of 46.6 ± 0.4% after 120 days was seen upon adding SF. The antibacterial activity of fibers against Escherichia coli (20.7 ± 0.16 mm) and Staphylococcus aureus (20.5 ± 0.4 mm) demonstrated significant antibacterial activity. The growth curve studies and biofilm inhibition tests from OD measurements showed self-inducing antibacterial activity from the hydrothermal deposition of Cu NPs. The 3T3 L1 and NIH 3T3 cells attached firmly and proliferated well on scaffolds with SF and Cu NPs. The measured cell viability was >300% and ≈200% in all composite scaffolds.

Thermal conductivity enhancement of diatomite-based composite phase change materials by interfacial reduction deposition of Cu nanoparticles

Phase change materials (PCMs) with high thermal storage density and constant working temperature suffer from low thermal conductivity, hindering their large-scale application. Herein, in situ reduction deposition of Cu, a relatively inexpensive and highly thermally conductive metal, on PCM carrier has been proposed to mitigate the low thermal conductivity issue of PCMs. Specifically, through the in-situ reduction method, the copper nanoparticles (Cu NPs) are firstly deposited on the surface and in the pore channels of the carrier (i.e., diatomite). Then the Cu-deposited diatomite was used to encapsulate paraffin as PCM to prepare composite phase change materials (CPCMs). The latent heat of the prepared CPCMs reached 78.6 J/g, and the associated thermal conductivity reached 0.561 W m−1 K−1, which is 97.5 % and 48.9 % higher than that of paraffin and paraffin/diatomite, respectively. Compared with the traditional method of simply adding thermal conductive particles, the proposed in-situ deposition method is more effective owing to the reduced contact thermal resistance between the interfaces of different materials. The prepared CPCM was an ideal candidate for energy storage due to its high latent heat, good thermal conductivity, appropriate phase change temperature, good shape stability, thermal stability, and thermal reliability. As such, the study results provide a new, low-cost and effective method for the thermal conductivity enhancement of CPCMs.

Copper nanoparticles-modified Na0.5Bi4.5Ti4O15 micron-sheets as a highly efficient and low cost piezo-photocatalyst

The coupling of piezoelectric effect and metal surface modification is an effective way to improve photocatalytic performance. Herein, we prepared a new piezoelectric heterojunction catalyst by depositing Cu nanoparticles on the surface of lead-free Na0.5Bi4.5Ti4O15 (NBT) piezoelectric micron-sheets. Under the simultaneous excitation of light and stirring, NBT@6.4 wt%Cu photocatalyst exhibits excellent piezo-photocatalytic activity, in which the degradation rate of methyl orange (MO) solution can reach 96% within 120 min, and the rate constant kobs value is as high as 24.67 × 10−3 min−1, which is ∼ 13 times larger than that of pure NBT photocatalyst under the excitation of light. The improved piezo-photocatalytic performance is attributed to that the deposition of Cu nanoparticles and the high piezoelectric properties of NBT facilitates the transfer and separation of photogenerated carriers. This work provides a new option for designing high-performance piezo-photocatalysts for pollutant treatment.

Synthesis and Structural studies of lightweight CNT/Cu composites: An overview

An overview on structural and electrical properties of carbon nanotubes (CNTs) and Copper (Cu) based composite is presented keeping in mind their applications today and in the near future. CNTs are emerging as the most promising conducting wires in interconnection technology due to their higher electrical conductivity and extraordinary current-carrying capacity. In this work, we have found that, metal sputtering technique proved useful for the deposition of Cu nanoparticles on the surface of nanotubes. The structural and morphological studies of Cu deposited nanotubes were investigated by Raman spectroscopy and scanning electron microscopy (SEM). It was found that, the presence of prominent Raman bands in Cu deposited nanotubes is clear indication of the nanocompoites formation without destruction of carbon tubular structure. CNTs/Cu composites showed high conductivity and ampacity, making it uniquely suited for applications in microscale electronics and inverters.

Influence of sub-zero temperature on nucleation and growth of copper nanoparticles in electrochemical reactions

SummaryCu metal nanostructures have attracted wide interest of study as catalysts for CO2 reduction reaction and other applications. Controlling the structure and morphology of Cu nanostructures during synthesis is crucial for achieving desired properties. Here, we studied temperature effects on electrochemical deposition of Cu nanoparticles. We found the size, nucleation density, and crystallinity of Cu nanoparticles are strongly influenced by low temperature processing. The electrodeposition at low temperature (−20°C) results in clusters of assembled small Cu nanoparticles, which is distinctly different from the large individual highly crystalline Cu nanoparticles obtained from the room temperature process. The differences in Cu nanoparticle morphology and crystallinity are attributed to the variations in reduction reaction rate and surface diffusion. The limitation of the reaction rate promotes multiple nuclei, and low surface diffusion induces poor crystallinity. This study deepens our understanding of low-temperature effects on electrochemical processes assisting the design of diverse hierarchical catalytic materials.

Growth of hard nanostructured ZrN surface induced by copper nanoparticles

Surfaces with defined nanoroughness and topography are appreciated in many applications. However, such surfaces, often built from deposited nanoparticles, suffer from low hardness and overall mechanical stability. This paper reports the research of ZrN surfaces with defined nanoroughness attained by seed-like growth evoked by Cu nanoparticles. The two-step process consists of (i) deposition of Cu nanoparticles by gas aggregation forming seeds (ii) growth of ZrN with surface nanoarchitecture. Our study faces the challenge to stabilize soft Cu nanoparticles by coating them with a hard, crystalline ZrN film deposited by High Power Impulse Magnetron Sputtering (HiPIMS) without any post thermal annealing which can be useful for coating heat-sensitive substrates. It is shown that by tailoring the HiPIMS process we were able to deposit hard Cu/ZrN nanocomposite with roughness and morphology predetermined by the Cu nanoparticles. Nano-indentation carried out with a resolution below 1 nm, confirmed sufficient nanohardness of CuNPs/ZrN nanocomposite.

Copper-zinc oxide heterojunction catalysts exhibiting enhanced photocatalytic activity prepared by a hybrid deposition method.

Heterojunction copper–zinc oxide catalysts were prepared by a hybrid two-step methodology comprising hydrothermal growth of ZnO nanorods (ZnO-NR) followed by deposition of Cu2O nanoparticles using an advanced gas deposition technique (AGD). The obtained bicatalysts were characterized by SEM, AFM, XRD, XPS, PL and spectrophotometry and revealed well-dispersed and crystalline Cu2O nanoparticles attached to the ZnO-NR. The adsorption properties and photocatalytic degradation of Orange II dye in water solutions were measured. It was found that the bicatalysts exhibited a conversion rate and quantum yield that both were about 50% higher compared with ZnO-NR alone, which were attributed to the intrinsic electric field created at the p–n junction formed at the Cu2O/ZnO interface facilitating charge separation of electron–hole pairs formed upon interband photon absorption. The interpretation was evidenced by efficient quenching of characteristic deep level ZnO photoluminescence bands and photoelectron core-level energy shifts. By comparisons with known energy levels in Cu2O and ZnO, the effect was found to be most pronounced for the non-polar ZnO-NR side facets, which accounted for about 95% of the exposed surface area of the catalyst and hence the majority of dye adsorption. It was also found that the dye adsorption capacity of the ZnO nanorods increased considerably after Cu2O deposition thereby facilitating the oxidation of the dye. The results imply the possibility of judiciously aligning band edges on structurally controlled and well-connected low-dimensional semiconductor nanostructures using combined two-step synthesis techniques, where in particular vacuum-based techniques such as AGD allow for growth of well-connected nanocrystals with well developed heterojunction interfaces.

Superhydrophobic and antibacterial wood enabled by polydopamine-assisted decoration of copper nanoparticles

Wood veneer had been widely used in interior decoration or fitment, but its application was still limited due to deformation after absorbing water and bacterial erosion. In this paper, a Cu coating owned superhydrophobic and antibacterial capabilities on wood veneer was fabricated by a facile and valid method. The wood veneer with superhydrophobic and antibacterial properties was prepared by self-polymerization of dopamine, chemical deposition of Cu nanoparticles, and hydrophobic modification using fluorosilane. The water contact angle and sliding angle of obtained Cu coating reached 155.7° and 4°, respectively. Meanwhile, the as-prepared coating showed resistance to acid or base solutions with different pH values, different temperatures aging and mechanical damages, and also displayed a good self-cleaning ability. In addition, the modified wood exhibited outstanding antibacterial activities towards Escherichia coli and Staphylococcus aureus. This work supplied a novel way to endow the superhydrophobic and antibacterial properties on wood veneer, and promote its multifunction application.

Embedded CuO nanoparticles@TiO2-nanotube arrays for photoelectrocatalytic reduction of CO2 to methanol

Herein, we report a simple approach to synthesize high-performance and structurally stable CuO nanoparticles catalyst embedded in TiO2 nanotube arrays for CO2 reduction. To summarize, anodic TiO2 nanotube arrays (TNTs) were electrochemical reductive doped in 1 mol/L (NH4)2SO4 solution to form an activated surface. Then CuO nanoparticles were successfully filled into the pores pace of TNTs by electrodeposition and heat treatment. The effects of Ti(Ⅲ) reduction doping were discussed by means of electrochemical impedance spectroscopy (EIS) and X ray photoelectron spectroscopy (XPS). Results show that partial Ti(Ⅳ) in TNTs can be reduced to Ti(Ⅲ) by electrochemical reduction, which leads to a significant improvement in TNTs surfactivity and then benefits the deposition of Cu nanoparticles to form a stable embedded structure. As a consequence, the composite electrodes showed higher photoelectrocatalytic performance for CO2 reduction. The maximum current of CuO-TNTs composite electrodes is up to −1.37 mA/cm2 at −0.5 V and high selectivity for methanol synthesis is also obtained in this case. At the same time, the amount of methanol produced by the CuO/self-doped TNTs composite electrode is about 15% higher than that by the CuO/TNTs electrode without reductive doping.

Uniform and Homogeneous Growth of Copper Nanoparticles on Electrophoretically Deposited Carbon Nanotubes Electrode for Nonenzymatic Glucose Sensor

The multiwalled carbon nanotubes thin-film-based electrode was fabricated by electrophoretic deposition and modified with copper (Cu) nanoparticles to fabricate Cu/CNTs nanocomposite sensor for nonenzymatic glucose detection. The expensive glassy carbon electrode was replaced by fluorine-doped tin oxide glass containing CNTs film to confine the Cu nanoparticles growth by electrodeposition through cyclic voltammetry (CV). The ultraviolet visible and X-ray diffraction analysis revealed the successful deposition of Cu nanoparticles on the CNTs-modified electrode. The atomic force microscopy images confirmed the morphology of electrodeposited Cu on CNTs film as uniformly dispersed particles. The electrocatalytic activity of electrode to the glucose oxidation was investigated in alkaline medium by CV and amperometric measurements. The fabricated sensor exhibited a fast response time of less than 5 s and the sensitivity of 314 μA mM−1 cm−2 with linear concentration range (0.02–3.0 mM) having detection limit 10.0 μM. Due to simple preparation of sensor, Cu/CNTs nanocomposite electrodes are a suitable candidate for reliable determination of glucose with good stability.

Effects of the Electrodeposition Time in the Synthesis of Carbon-Supported Pt(Cu) and Pt-Ru(Cu) Core-Shell Electrocatalysts for Polymer Electrolye Fuel Cells

Pt(Cu)/C and Pt-Ru(Cu)/C electrocatalysts with core-shell structure supported on Vulcan Carbon XC72R have been synthesized by potentiostatic deposition of Cu nanoparticles on the support, galvanic exchange with Pt and spontaneous deposition of Ru species. The duration of the electrodeposition time of the different species has been modified and the obtained electrocatalysts have been characterized using electrochemical and structural techniques. The High Resolution Transmission Electron Microscopy (HRTEM), Fast Fourier Transform (FFT) and Energy Dispersive X-ray (EDX) microanalyses allowed the determining of the effects of the electrodeposition time on the nanoparticle size and composition. The best conditions identified from Cyclic Voltammetry (CV) corresponded to onset potentials for CO and methanol oxidation on Pt-Ru(Cu)/C of 0.41 and 0.32 V vs. the Reversible Hydrogen Electrode (RHE), respectively, which were smaller by about 0.05 V than those determined for Ru-decorated commercial Pt/C. The CO oxidation peak potentials were about 0.1 V smaller when compared to commercial Pt/C and Pt-Ru/C. The positive effect of Cu was related to its electronic effect on the Pt shells and also to the generation of new active sites for CO oxidation. The synthesis conditions to obtain the best performance for CO and methanol oxidation on the core-shell Pt-Ru(Cu)/C electrocatalysts were identified. When compared to previous results in literature for methanol, ethanol and formic acid oxidation on Pt(Cu)/C catalysts, the present results suggest an additional positive effect of the deposited Ru species due to the introduction of the bifunctional mechanism for CO oxidation.

Cu nanoparticles electrodeposited at liquid-liquid interfaces: a highly efficient catalyst for the hydrogen evolution reaction.

The electrochemical deposition of Cu nanoparticles with an average diameter of approximately 25-35 nm has been reported at liquid-liquid interfaces by using the organic-phase electron-donor decamethylferrocene (DMFc). The electrodeposited Cu nanoparticles display excellent catalytic activity for the hydrogen evolution reaction (HER); this is the first reported catalytic effect of Cu nanoparticles at liquid-liquid interfaces.

Graphene oxide doped poly(3,4-ethylenedioxythiophene) modified with copper nanoparticles for high performance nonenzymatic sensing of glucose.

A highly stable and sensitive nonenzymatic glucose sensor was successfully constructed through a facile electrodeposition method. Graphene oxide (GO) doped poly(3,4-ethylenedioxythiophene) (PEDOT) was first electrodeposited onto a glass carbon electrode using cyclic voltammetry and copper nanoparticles were then electrodeposited onto the rough surface of the PEDOT/GO nanocomposite through electrochemical reduction in a solution containing copper cations. The modified electrode was used for reliable nonenzymatic electrochemical detection of glucose, and under optimized conditions, it exhibited a high sensitivity of up to 909.1 μA mM-1 cm-2 and a very fast response time of less than 1 s, with a wide linear range of 0.1 μM to 1.3 mM and a low detection limit of 47 nM. This nonenzymatic glucose sensor was, furthermore, highly stable and unresponsive to potentially interfering substances, and it could be used for the assay of glucose in real human serum samples. These enhanced sensing performances were ascribed to the close contact of copper nanoparticles onto the rough surface of the PEDOT/GO conducting polymer nanocomposite, which has good conductivity and very high surface area that can act as an excellent substrate for the growth and support of copper nanoparticles. All these results indicate that this electrochemical sensor is highly promising for nonenzymatic glucose detection.

Photoassisted Immersion Deposition of Cu Clusters onto Porous Silicon: A Langmuir–Hill Ligand–Locus Model Applied to the Growth Kinetics

Cu–porous silicon (Cu–PS) composite materials consisting of nanosized Cu clusters preferentially grown on the surface of PS were fabricated by photoassisted deposition of Cu nanoparticles onto PS. Structural and chemical characterization of the Cu particles grown in the PS matrix has been carried out by synchrotron X-ray absorption spectroscopy, from which different reaction stages have been identified within the photoassisted reaction. In particular, it was found that the reduction of Cu occurs in three main phases: (a) Cu nucleates homogeneously in a few seconds over the surface of PS by a coupled red-ox reaction; (b) clusters grow by new reduced ions, which tend to oxidize the previously deposited Cu atoms making increasingly heterogeneous Cu clusters; and (c) a competitive process between nucleation of new clusters and cluster coalescence gives rise to a bulklike Cu thin film. It was determined that the structures formed in the first two phases display surface plasmon resonance, with band intensity and broadening consistent with the increasing heterogeneity of the clusters. The growth kinetics has been fitted to a Langmuir–Hill model. Following these results, a reaction model has been proposed to explain the mechanisms involved in the first stages of Cu clustering.

Preparation and Tribological Properties of Surface-Capped Copper Nanoparticle as a Water-Based Lubricant Additive

Cu nanoparticle surface-capped by methoxylpolyethyleneglycol xanthate was synthesized using in situ surface-modification technique. The size, morphology and phase structure of as-prepared Cu nanoparticle were analyzed by means of X-ray diffraction and transmission electron microscopy. The tribological properties of as-synthesized Cu nanoparticle as an additive in distilled water were investigated with a four-ball machine, and the morphology and elemental composition of worn steel surfaces were examined using X-ray photoelectron spectroscopy and scanning electron microscope equipped with an energy-dispersive spectrometer attachment. Results show that as-synthesized Cu nanoparticle as a water-based lubricant additive is able to significantly improve the tribological properties and load-carrying capacity of distilled water, which is ascribed to the deposition of Cu nanoparticles on steel sliding surfaces giving rise to a protective and lubricious Cu layer thereon. In the meantime, they may also tribochemically react with rubbing steel surfaces to generate a boundary lubricating film consisting of Cu, FeS and FeSO4 on the rubbed steel surface, which helps to result in greatly improved tribological properties of distilled water, thereby reducing friction and wear of the steel–steel pair.

Electrochemical Reduction of Carbon Dioxide over CNT‐Supported Nanoscale Copper Electrocatalysts

This paper presents the experimental investigation of copper loaded carbon nanotubes (CNTs) electrocatalysts for the electrochemical reduction of carbon dioxide. The electrocatalysts were synthesized by homogeneous deposition precipitation method (HDP) using urea as precipitating agent. The prepared catalysts were characterized by TEM, SEM, XRD, XPS, BET, and FTIR for their morphology and structure. Characterization results confirm the deposition of Cu nanoparticles (3–60 nm) on CNTs. Linear sweep voltammetry (LSV) and chronoamperometry (CA) were used to investigate the activity of the as‐prepared catalysts for the electrochemical reduction of carbon dioxide. The electrocatalysts reduced CO2 with high current density in the potential range 0~−3 V versus SCE (standard calomel electrode). Among all catalysts tested, 20 wt. % copper loaded CNTs showed maximum activity. Gas chromatograph with TCD was used to analyze liquid phase composition. The faradaic efficiency for methanol formation was estimated to be 38.5%.

Aerobic Oxidation of Thiols Catalyzed by Copper Nanoparticles Supported on Diamond Nanoparticles

AbstractAfter purification by Fenton treatment, commercial diamond nanoparticles (NPs) are a suitable solid support for the deposition of Cu nanoparticles. Heating at 500 °C under hydrogen proved to be a convenient annealing process for Fenton‐purified diamond NPs that decreased the population of surface carboxylic acid groups and lead to samples with average Cu particle sizes of 3–4 nm. The samples of Cu NPs supported on diamond NPs have been characterized by IR and X‐ray photoelectron spectroscopy, as well as XRD and TEM. It was concluded that the samples contained Cu0 as well as CuI and CuII species. The resulting diamond‐supported Cu NPs were highly active for the selective aerobic oxidation of aromatic thiols to the corresponding disulfides, whereas aliphatic thiols exhibited much lower reactivity because of some poisoning and catalyst deactivation produced by aliphatic thiols. The Cu catalysts used for thiophenol oxidation could be reused in four consecutive runs with 4 % of decrease in the catalytic activity. This Cu catalyst exhibited similar catalytic activity, but is considerably more affordable, as an analogous diamond‐supported Au catalyst.

Deposition of Cu Nanoparticles on the Surface of Metallic Aluminum

Deposition of Cu particles by electrolysis at constant electrode potential and by internal electrolysis methods was investigated. The composition of deposited material was confirmed by optical and scanning electron microscope methods. Combination of electrolysis at constant electrode potential with internal electrolysis method was found most effective for fabrication of nanoparticle arrays. Single crystalline Cu particles are fabricated by internal electrolysis, while polycrystalline ones obtained by combined chronopotentiometric and internal electrolysis methods. The formation mechanism of Cu nanoparticles is described.

Preparation of highly dispersed CuPt nanoparticles on ionic-liquid-assisted graphene sheets for direct methanol fuel cell

In this work, CuPt nanocomposites were decorated on ionic-liquid-assisted graphene and their electrocatalytic activities for methanol oxidation were investigated. The procedure involved the synthesis of graphene by electro-oxidation of pure graphite in an ionic-liquid/water solution, followed by the deposition of Cu nanoparticles on graphene and their further reduction of chloroplatinic acid. The catalysts were characterized by using transmission electron microscopy, X-ray photoelectron spectroscopy, infrared spectroscopy, Raman spectroscopy and X-ray diffraction. Subsequently, electrocatalytic activities of this catalyst for methanol oxidation were measured by cyclic voltammetry, chronoamperometry and CO-stripping voltammetry. Results showed that the electrocatalytic activity and stability of CuPt/ionic-liquid-assisted graphene for methanol oxidation was better than that on commercial carbon blacks, which was attributed to the increase of the graphene conductivity by ionic liquid and the facile removal of intermediate poisoning species with the aid of Cu, demonstrating that ionic-liquid-assisted graphene can be an alternative support for Pt immobilization in direct methanol fuel cells.

N-doped TiO2 P25/Cu powder obtained using nitrogen (N2) gas plasma

It has been shown that the photocatalytic activity of TiO2 can be modified by deposition of Cu nanoparticles as well as doping with nitrogen. Typical procedures to induce the doping of titania are based on chemical methods. An interesting alternative is to dope titania by using N2 gas plasma in the presence of a metal. In this work, it is shown that doping of titania Degussa P25, in the presence of copper using N2 gas plasma can induce also the deposition of Cu nanoparticles. This material, known as N-doped TiO2/Cu is characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and UV–Vis diffuse reflectance. Additionally, the photocatalytic activity of the samples was evaluated by monitoring the photodegradation of methylene blue solutions using UV–Vis absorption analysis in the range 250–850nm. The results show that this methodology of incorporating Cu into titania P25 to obtain N-doped TiO2/Cu increases its photocatalytic activity when low intensity gas plasma is used.