Surface Of Copper Nanoparticles Research Articles

Dual functionalized copper nanoparticles for thermoplastics with improved processing and mechanical properties and superior antibacterial performance.

The utilization of metal nanoparticles for antibacterial thermoplastic composites has the potential to enhance the safety of human and animal life by mitigating the spread and transmission of foodborne pathogenic bacteria. The dispersion, antioxidant and antimicrobial activities of metal nanoparticles directly affect the application performance of the composites. This study focused on achieving amine-carboxyl co-modified copper nanoparticles (Cu-AC) with excellent antioxidant properties and monodispersity through in situ grafting of amine and carboxyl groups onto the surface of copper nanoparticles via ligand interaction. Polyacrylic acid's extended carbon chain structure was utilized to improve its dispersion and antioxidant properties, and its antibacterial properties were synergistically enhanced using secondary amines. It was found that Cu-AC possesses high antibacterial properties, with a minimum inhibition concentration of 0.156 mg mL-1. Antibacterial masterbatches and their composites (polypropylene/Cu) manufactured by melt blending of polypropylene and Cu-AC exhibited excellent antibacterial rates of up to 90% and 99% at 300 ppm and 700 ppm Cu-AC, respectively. Additionally, Cu-AC bolstered the thermal degradation, processing and mechanical properties of polypropylene. The successful implementation of this product substantiates the potential applications of polypropylene/Cu composite materials across diverse industries.

Development and application of nanocatalysts for processing synthesis gas into methanol

This article presents a study on the development and improvement of nanoscale heterogeneous nanocatalysts based on copper and zinc oxide for the subsequent processing of synthesis gas into methanol. An analytical review of modern types of nanocatalysts is presented, general information about the types of nanocatalysts for methanol production is provided, a patent search is performed, methodological approaches to the development of new and improvement of existing nanocatalysts are substantiated. The results of laboratory studies related to the creation of structures of new types of nanocatalysts are presented, their optimal composition is justified and computer modeling using the "Material Studio" program is carried out. Modifications of nanocatalyst matrices, promoters, and Cu/Zn ratios in catalysts have been investigated. The mechanism of chemical reactions occurring on the surface of metal nanoparticles during the production of methanol from synthesis gas is described, the process of adsorption of CO on the surface of copper nanoparticles is modeled, the process of separation and production of methanol is shown, the activation energy of the chemical reactions occurring is calculated. Models have been developed for: nanoparticles based on Cu and ZnO; adsorption of CO on the surface of nanoparticles; addition of hydrogen to the surface of nanoparticles; production of methanol on the surface of nanoparticles with the calculation of the activation energy of chemical reactions on the surface of nanoparticles. A technological scheme for the production of methanol using a nanostructured bimetallic catalyst has been developed. It is shown that the obtained nanocatalysts based on Cu and ZnO have optimal catalytic properties for laboratory experiments.

Fabrication of multilayer Graphene-coated Copper nanoparticles for application as a thermal interface material

A process to fabricate a thermal interface material (TIM) was developed to coat graphene, which is chemically stable and thermally conductive, on the surface of copper nanoparticles (CNPs) to prevent their oxidation while promoting heat dissipation. The CNPs were synthesized using the polyol method to convert polyvinylpyrrolidone (PVP) into multilayer graphene (MLG) via chemical vapor deposition (CVD). For optimization, CVD temperature, the amount of additional PVP solution, and PVP molecular weight (MW) in polyol process were varied. The results showed that thermal properties degraded with increasing residual PVP, and an increasing ID/IG ratio confirmed improved MLG quality. The optimal MLG coating conditions were found to be a CVD temperature of 880℃, 50 wt% additional PVP solution and using K30 PVP in polyol process (MW: 45,000). These conditions provided the highest thermal conductivity of 19.66 W/m∙K. Thermogravimetric analysis established that oxidation began at 150℃, which is higher than the upper temperature limit of electronic components. Therefore, MLG-coated CNPs would be suitable as TIM.

Advanced utilization of copper in waste printed circuit boards: Synthesis of nano-copper assisted by physical enrichment

The copper in the waste printed circuit boards (WPCBs) is cleanly recycled by physical methods and presented in the form of nano copper particles by hydrometallurgical, which provides environmental approach to the advanced utilization of metal copper. Copper in WPCBs was first pre-concentrated by gradient enrichment process including gravity separation, mechanical grinding and flotation. The leaching method was then used to dissolve copper from the flotation concentrate in ammoniacal/ammonium salt solutions. Subsequently, reduction treatment was conducted to synthesize nano-copper from leaching solution. The enrichment results of the clean physical separation process show that the grade of copper increased from 16.22% to –38.05% by gravity separation, and the grade of copper further increased to 72.62 % by flotation after dissociation, which avoids overgrinding of low value components. Copper nanoparticles can be prepared effectively, and the recovery of copper in the leaching process reaches 99 %. The particle size of copper nanoparticles obtained by ascorbic acid reduction is tens of nanometers, and the surface of copper nanoparticles is smooth and nearly spherical. The present study proposes an environmentally friendly process of preparing nano-copper from the copper in WPCBs.

Colorimetric Determination of Amino Acids using Fluorescent Copper Nanoparticle

Among the 20 amino acids, cysteine plays a major role in communication of the cells, especially towards immune system and thus developing sensor for cysteine is very important to understand the status of the human health. Copper nanoparticles decorated with Rhodamine B (RBCN) have the potential to detect the biologically important species such as amino acids, especially cysteine. RBCN has been previously has demonstrated for the sensing of host molecules such as cucurbituril based on the relative binding potential of rhodamine B on the surface of copper nanoparticles. Based on that concept, now we have developed the sensor for amino acids, especially for the cysteine

Self-Supporting Dendritic Copper Porous Film Inducing the Lateral Growth of Metallic Lithium for Highly Stable Li Metal Battery

Lithium metal is recognized as the most promising anode candidate for advanced high-energy-density batteries. However, uncontrolled vertical growth of Li dendrites will induce short-circuit and cause rapid capacity loss, which hinders the practical application of rechargeable Li-metal batteries. The regulation of Li dendrites from vertical to lateral growth may be an effective strategy to solve the problems. Herein, a self-supporting dendritic copper porous film as host matrix of lithium is constructed by a one-step facile and cost-effective electrodeposition on gas-liquid-solid interface to inhibit the vertical growth of Li dendrites. Li nucleates on the surface of copper nanoparticles and grows laterally by the induced action of lateral copper dendrites consisting of nanoparticles. Meanwhile, copper porous film with dendritic walls provides more nucleation sites for uniform Li deposition and space for Li storage. On this basis, high and stable Coulombic efficiency of 98% after 600 cycles at 1 mA cm−2 and prolong lifespan of 2400 h in the symmetric cell are achieved. Coupled with a LiFePO4 cathode, the full cell exhibits good rate performance and cycle stability with capacity retention of 82.4% for 250 cycles at 1 C. It provides a simple but effective way to realize a stable Li metal-based anode.

One‐step synthesis of oxidation‐resistant Cu@Ag core–shell nanoparticles

One-step synthesis of wet chemical method is proposed for the preparation of core–shell nanostructures of copper and silver. This facile and environment friendly fabrication simplifies the surface treatment of copper particles to avoid copper core to be oxidised before coating silver. The thermal stability against oxidation and electrical properties of Cu@Ag core–shell nanoparticles are investigated. The results show that Cu@Ag core–shell nanoparticles possess high spherical degree, and the silver is evenly coated on the surface of copper nanoparticles. The synthesised spherical Cu@Ag core–shell nanoparticles exhibit excellent thermal stability at the high temperature of 300°C. After annealing at 200°C for 30 min, the sheet resistance of the spherical Cu@Ag core–shell nanoparticles (Ag content 7.68 wt%) is extremely low (69.82 μΩ cm).

Copper nanoparticle heterogeneous catalytic 'click' cycloaddition confirmed by single-molecule spectroscopy.

Colloidal or heterogeneous nanocatalysts can improve the range and diversity of Cu(I)-catalysed click reactions and facilitate catalyst separation and reuse. Catalysis by metal nanoparticles raises the question as to whether heterogeneous catalysts may cause homogeneous catalysis through metal ion leaching, since the catalytic process could be mediated by the particle, or by metal ions released from it. The question is critical as unwanted homogeneous processes could offset the benefits of heterogeneous catalysis. Here, we combine standard bench scale techniques with single-molecule spectroscopy to monitor single catalytic events in real time and demonstrate that click catalysis occurs directly at the surface of copper nanoparticles; this general approach could be implemented in other systems. We use 'from the mole to the molecule' to describe this emerging idea in which mole scale reactions can be optimized through an intimate understanding of the catalytic process at the single-molecule-single catalytic nanoparticle level.

Double oxide shell layer formed on a metal nanoparticle as revealed by aberration corrected (scanning) transmission electron microscopy

Determining the extent of oxidation in batches of metal nanoparticles is essential to predict the behaviour of the material. Using aberration corrected transmission electron microscopy (TEM) it was possible to detect the formation of an oxide shell, of thickness 3 nm, on the surface of copper nanoparticles. Further analysis showed that this shell actually consists of two layers, both of which were polycrystalline in nature with domains in the size range of 1–2 nm, and having a thickness of 1.5 nm each. Energy dispersive x-ray spectroscopy confirms that the layers arise due to the formation of oxides, but it was not possible to determine their exact nature. Analysis of the intensity variation within images obtained via probe corrected scanning TEM combined with a high angle annular dark field detector indicates that the shell consists of an inner layer of cuprous oxide (Cu2O) and an outer layer of cupric oxide (CuO). This work was complemented by conventional TEM which provided size distribution and revealed that the majority of particles have a core consisting of a single crystal of copper. This demonstrates the ability of TEM to help to determine the oxidation state of nanoparticles and its potential to be applied to a wide range of homogenous and heterogeneous nanoparticles.

Synthesis and Characterization of Copper-Silver Core-Shell Nanoparticles by Polyol Successive Reduction Process

ABSTRACTIn this work, spherical copper (core) - silver (shell) nanoparticles with diameter of 40-50 nm were synthesized through polyol successive reduction process in glycerol with addition of sodium hydroxide (NaOH). The process involves microwave-assisted reduction of copper nitrate by glycerol under atmospheric conditions and successive reduction of silver nitrate at the surface of copper nanoparticles synthesized. We investigated the influence of synthesis parameters including molar ratio of NaOH:Cu (0:1, 1:1, 3:1 and 5:1), the molar ratio of Ag:Cu (0.01:1, 0.05:1, 0.10:1, 0.15:1 and 0.20:1) on the size, structure and composition of the resulting particles. High-resolution transmission electron microscopy with energy dispersive X-ray spectroscopy (TEM/EDS), scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis were used to characterize the particles obtained. The average size of the nanoparticles decreased with increasing of the ratio of sodium hydroxide. With the molar ratio of Ag:Cu greater than 0.05:1, the silver protective shell can prevent forming of copper oxide on the surface of nanoparticles.

Facilitated CO2 transport membranes utilizing positively polarized copper nanoparticles

We suggest copper nanoparticles as a CO(2) carrier by employing the ionic liquid BMIM(+)BF(4)(-) for facilitated transport membranes. The copper nanoparticles were prepared by dissociating the copper metal into the ionic liquid as a facile synthesis. The interactions between BF(4)(-) of the ionic liquid and the surface of copper nanoparticles caused the Cu surface to be partially positively charged, resulting in increased activity in copper-CO(2) complexation.

One-Pot, Single Step Green Synthesis of Copper Nanoparticles: SPR Nanoparticles

ABSTRACT A one-pot and single-step reduction process for producing copper nanoparticles will be described. This process can be carried out at room temperature and nanocrystalline size is achieved by using greener stabilizing agent starch with hydrazine hydrate as a reducing agent in ambient condition. TEM images show that the particles formed are of spherical morphology and strongly support size distribution. FTIR spectra show that there is thin layer of starch molecule on the surface of copper nanoparticles that stabilize and protect it from air oxidation for several days. The synthetic procedure is the typical example for green synthesis of Cu nanoparticles at room temperature.

Experimental and Theoretical Studies of 1, 3-diaminopropylene Derivatives as Poten- tial Antioxidative Agents for Copper Nanoparticles in Hydrothermal System

Novel 1,3-diamino-propylene derivatives as potential corrosion inhibitors for copper nanoparticles has been studied by density functional theory (DFT) calculations, Fourier transform infrared spectra (FTIR), thermogravimetric and Zeta potential analysis. 1,3-Dimorpholin-propylene was considered to be the most promising inhibitor for copper nanoparticles. Thermogravimetric results indicated the oxidation temperature of copper nanoparticles decreased from 286.50 oC (blank) to 270.1 oC (inhibitor). FTIR spectra indicated the addition of inhibitor could optimize the adsorption behavior of surfactant molecules on the surface of copper nanoparticles. Zeta potential results showed 1,3-dimorpholin-propylene could improve the stability of copper nanoparticles (~0 mV for blank, and -2.5 mV for inhibitor).

Formation of air-stable copper–silver core–shell nanoparticles for inkjet printing

Copper nanoparticles can be utilized as a low-cost replacement for silver and gold nanoparticles which are currently used in inkjet printing of conductive patterns. However, the main obstacle for using copper nanoparticles is their spontaneous oxidation at ambient conditions. Here we describe the synthesis of nonoxidizable copper nanoparticles by coating them with a silver shell, and inkjet printing of these particles. The formation of these core–shell nanoparticles is driven by a transmetalation reaction on the surface of copper nanoparticles, where the copper atoms present on the particles' surface are used as the reducing agent for the silver. This process results in formation of solely copper–silver core–shell nanoparticles, with no individual silver particles. It was found that coating 40 nm copper nanoparticles with a 2 nm layer of silver prevents oxidation of the copper core and preserves its metallic characteristic. Characterization of these nanoparticles by HR-TEM, SEM, EDS, XRD, spectrophotometry and XPS confirm the core–shell structure and their stability to oxidation. Inkjet printing of concentrated aqueous dispersions of these copper–silver nanoparticles was done on various substrates, and it was found that conductive and decorative patterns with metallic appearance, stable to oxidation (up to 150 °C) are formed.