Nanostructured Copper Research Articles

Essential oil mediated synthesis and application of highly stable copper nanoparticles as coatings on textiles and surfaces for rapid and sustained disinfection of microorganisms

Rampant pathogenesis induced by communicable microbes has necessitated development of technologies for rapid and sustained disinfection of surfaces. Copper nanoparticles (CuNPs) have been widely reported for their antimicrobial properties. However, nanostructured copper is prone to oxidative dissolution in the oil phase limiting its sustained use on surfaces and coatings. The current study reports a systematic investigation of a simple synthesis protocol using fatty acid stabilizers (particularly essential oils) for synthesis of copper nanoparticles in the oil phase. Of the various formulations synthesized, rosemary oil stabilized copper nanoparticles (RMO CuNPs) were noted to have the best inactivation kinetics and were also most stable. Upon morphological characterization by TEM and EELS, these were found to be monodispersed (φ 5–8 nm) with copper coexisting in all three oxidation states on the surface of the nanoparticles. The nanoparticles were drop cast on woven fabric of around 500 threads per inch and exposed to gram positive bacteria (Staphylococcus aureus), gram negative bacteria (Escherichia coli and Pseudomonas aeruginosa), enveloped RNA virus (phi6), non-enveloped RNA virus (MS2) and non-enveloped DNA virus (T4) to encompass the commonly encountered groups of pathogens. It was possible to completely disinfect 107 copies of all microorganisms within 40 min of exposure. Further, this formulation was incorporated with polyurethane as thinners and used to coat non-woven fabrics. These also exhibited antimicrobial properties. Sustained disinfection with less than 9% cumulative copper loss for upto 14 washes with soap water was observed while the antioxidant activity was also preserved. Based on the studies conducted, RMO CuNP in oil phase was found to have excellent potential of integration on surface coatings, paints and polymers for rapid and sustained disinfection of microbes on surfaces.

Antiviral Coating for Mitigation of COVID-19 Pandemic: A Review on the Role of Nanomaterial for Safer Surface against COVID-19

The COVID-19 pandemic the world has been facing is caused by the novel coronavirus, SARS-CoV-2. The virus can remain on certain surfaces for an extended period. As a consequence, contact with the surfaces can cause a healthy human to contract the disease. Although certain household items work against contaminated surfaces, none of the disinfectants can be used for a considerable amount of time. Therefore, the assessment and use of non-corrosive and non-toxic disinfectants are critical to stop the infection from spreading. Copper, along with its compounds and polymers, CPEs and OPEs, and Carbon Nanomaterials have demonstrated effective antibacterial and antiviral activity against bacteria such as E. Coli, S. Aureus, and viruses such as Influenza A virus. This review investigates the potential of using these substances as a surface coating to render the SARS-CoV-2 virus inactive. In addition, the review summarizes helpful information regarding the antimicrobial and antiviral activity and mechanism of polymers, copper, and carbon nanostructures. It also discusses the efficacy of these functional coatings in deactivating the SARS-CoV-2 virus.

Decomposition and dewetting of super-saturated Cu-15 at. % Co solid solution film

Nano-structured copper thin films present numerous applications for miniaturization of electronic devices. Their long term stability is key for reliable functionality. This work explores the thermal stability and solid state dewetting of a Cu-Co solid solution thin film and compares it to pure Cu. As according to the phase diagram Co is practically immiscible in Cu at room temperature, a metastable solid solution of Cu-15 at. % Co was deposited as thin film on a sapphire wafer. The microstructural evolution of the Co super-saturated film at temperatures ranging from 673 to 1073 K was evaluated using X-ray diffraction and high resolution microscopy techniques such as scanning electron and transmission electron microscopy. Interestingly, there is a competition between grain growth and phase separation. Co precipitates at grain boundaries acting as pinning sites preventing rapid grain growth during heat treatment at intermediate annealing temperature. However, grain growth occurs very quickly at higher temperatures, once the elemental phases of Cu and Co are formed. The competition between grain growth and phase separation and their consequence for dewetting are discussed.

Towards transparent and durable copper-containing antimicrobial surfaces

Metallic copper is a potent antimicrobial agent with high efficacy against a range of microorganisms. Whilst it is commonplace for objects such as door handles and hospital bedrails to be made of or to be coated with copper, other high-touch surfaces such as those of screens and monitors would lose their optical transparency. Herein, we report the design of a transparent antimicrobial nanostructured copper surface obtained by dewetting ultrathin metal copper films on glass. Antimicrobial effectiveness of >99.9 % was obtained within 2 h against Staphylococcus aureus following the US Environmental Protection Agency Test method. Moreover, the proposed surfaces show an average transmittance between 70–80% with little color in the visible range. Additionally, they maintain optical and antimicrobial properties after abrasion and chemical exposure tests designed to replicate physical wear and repeated exposure to biocidal cleaning materials. With the demonstrated surfaces’ antimicrobial, colorless, and durability properties, they have potential in applications such as touch-enabled public or personal displays once higher transparency is achieved.

Finite element analysis of thermal sensitivity of copper nanorods, nanoellipsoids, nanospheres and core-shells for hyperthermia application

Hyperthermia is a cancer treatment strategy that involves raising the temperature of the afflicted tissues without disrupting the surrounding tissues. This study is focused on finite element analysis of copper, nanoellipsoids, nanorods, nanospheres and core-shells for potential hyperthermia application. The temperature of copper nanostructures was elevated using an external source to the desired temperature to destroy the cancerous cell. The COMSOL Multiphysics package was used to calculate how long it would take to achieve the desired temperature using different nanostructures of copper. Thermal sensitivity of the tested nanostructures was checked by putting them in a spherical domain of tissue. It was observed that copper nano-rod attained the highest temperature of 43.3 °C compared to other geometries. It was also found that these geometries attained thermal equilibrium just after 0.5 μs. However, the copper nano-ellipsoid had a higher core volume, which is utilized to determine the thermal sensitivity of the nanostructures. Noble metal (Au) coating was first found to be better than PEG polymer coating for investigating core–shell structures. The Au coating on the surface of the copper core resulted in a gradual decrease in temperature with an increasing volume coverage ratio. These results conclude that copper nanostructures can be suitable candidates for hyperthermia.

Evaluation of antibacterial activity and influencing factors of normal and nanostructured copper-based materials

BackgroundCopper-based materials have garnered extensive recognition for their effective nature against microorganisms and their minimal toxicity. However, the evaluation for their antibacterial activity is still in its nascent stages, and the evaluation results based on existing criteria are not representative of real-world application. AimTo evaluate the antibacterial activity and primary determinants of influence of copper-based materials in order to investigate their practical antibacterial activity and potential mechanisms of such materials. MethodsStaphylococcus aureus and Escherichia coli bacterial suspensions were applied via inoculation onto the surfaces of normal and nanostructured copper foil. Following incubation of the inoculated surfaces under diverse experimental conditions—including varying compositions of the bacterial suspension, the use of chemical neutralizers, the existence of organic interferents, and low temperature and humidity—surviving bacteria were enumerated. Using the scanning electron microscopy and X-ray photoelectron spectroscopy, the surface changes of copper-based materials were examined. FindingsFollowing 1 h of exposure to 37 °C and 90% relative humidity, Staphylococcus aureus was reduced by 4.45 log10 on normal copper foil, while all of the bacteria were eradicated on nanostructured copper foil. In addition, it was discovered that preparing a bacterial suspension with PBS results in a significant number of Escherichia coli fatalities during the test, whereas using TPS promotes the bacteria's normal growth. Furthermore, the outcomes of the antibacterial activity test were diminished when chemical neutralization was employed, and the presence of organic interferents had distinct impacts on normal copper foil and nanostructured copper foil. Additionally, low temperatures and humidity diminished the antibacterial activity of copper foil, whereas normal copper foil produced significantly better results. ConclusionWhile copper-based materials exhibit robust antibacterial activity as determined by standard assays, their efficacy in real-world applications is subject to various influencing mechanisms. In order to objectively evaluate the antibacterial activity of copper-based materials and provide precise guidance for their development and practical application, it is essential to regulate test conditions with targeted.

Laboratory High-Contrast X-ray Microscopy of Copper Nanostructures Enabled by a Liquid-Metal-Jet X-ray Source.

High-resolution imaging of Cu/low-k on-chip interconnect stacks in advanced microelectronic products is demonstrated using full-field transmission X-ray microscopy (TXM). The comparison of two lens-based laboratory X-ray microscopes that are operated at two different photon energies, 8.0 keV and 9.2 keV, shows a contrast enhancement for imaging of copper nanostructures embedded in insulating organosilicate glass of a factor of 5 if 9.2 keV photons are used. Photons with this energy (Ga-Kα radiation) are generated from a Ga-containing target of a laboratory X-ray source applying the liquid-metal-jet technology. The 5 times higher contrast compared to the use of Cu-Kα radiation (8.0 keV photon energy) from a rotating anode X-ray source is caused by the fact that the energy of the Ga-Kα emission line is slightly higher than that of the Cu-K absorption edge (9.0 keV photon energy). The use of Ga-Kα radiation is of particular advantage for imaging of copper interconnects with dimensions from several 100 nm down to several 10 nm in a Cu/SiO2 or Cu/low-k backend-of-line stack. Physical failure analysis and reliability engineering in the semiconductor industry will benefit from high-contrast X-ray images of sub-μm copper structures in microchips.

Study and Characterization of Copper and Titanium Oxides Nanostructures for Some Molecular and Biological Applications

In this work, Copper and Titanium nanocomposites (NPs) were prepared by mixture exchange process with ratios (25, 50 and 75 % CuO-TiO2). The biological activity was studied, and it was found that the concentrations of 50 and 100 µg/mL of 50 and 75 % CuO-TiO2 were the best concentrations, Low concentrations of the nanoparticle mixture at 25 µg/mL also stimulated the growth of symbiotic bacteria. The mixture of nanoparticles was easier to prepare and more effective in inhibiting bacterial growth. biochemical test and PCR were performed to confirm the identity of the studied bacteria. While isolating the bacteria, a new type of bacteria was detected and registered in the Global Gen Bank under accession No. OP942239. Surface and structure properties have been studied using FESEM, EDS analysis, XRD and FTIR respectively. It can be seen that the size and diameter of the nanocomposite increase with the weight ratio of CuO-TiO2. The aggregated CuO-TiO2 nanostructures with different ratios were transformed gradually into a uniform spherical shape. The average size of the CuO/TiO2 composite was found to be about 32.122, 29.865 and 27.607 nm at 25, 50 and 75 % CuO-TiO2 respectively. While the mean sizes of CuO and TiO2 were 25.35 and 34.38 nm respectively. The crystalline size decreases after the ion exchange process, which could be due to the diffraction peaks being broad in all the samples of Copper Titanate at the surface. Subsequently, adding Copper particles to the TiO2 film can improve the performance of the material. HIGHLIGHTSThe nanostructure CuO-TiO2 was created through various loading ratios. These NPs’ efficiency was calculated using a number of techniques, including FTIR, X-ray diffraction, EDS spectra, and FESEM. The observations indicate that molecular transition parameters play an essential role in determining the size, shape, and functionality of CuO- TiO2 NPs. The sharp peaks observed in the composites indicated higher crystallinity in CuO. In addition, two types of NPs have shown promising effects in inhibiting NPs aggregation and enhancing biological effects but the potential of these NPs against different bacteria may differ. Thus, further research and testing is needed to assess its efficacy and human health and environmental impact before considering its use. In conclusion, copper and titanium NPs have their distinct advantages in bacterial inhibition, and the choice between them should be based on specific conditions and environmentally friendly factors. GRAPHICAL ABSTRACT

A comprehensive review on the potential of copper spinel ferrite for gas sensing application

Copper spinel ferrite (CuFe₂O₄) is a promising material for the gas sensing due to its unique structural, electrical, and catalytic properties. This review focuses on the gas sensing capabilities of copper ferrite. Copper ferrite’s inverse spinel structure, rich in oxygen vacancies and flexible cation distribution, enables effective gas adsorption, making it highly sensitive to reducing and oxidizing gases. Various synthesis methods, determines the material’s particle size, morphology, and surface area, which are essential for optimizing gas sensing performance. Doping with the transition metals like nickel (Ni) and zinc (Zn) significantly enhances the material’s sensitivity, selectivity, response time, and operating temperature by increasing oxygen vacancies and improving charge transport. However, challenges remain, including high operating temperatures, cross-sensitivity to humidity, and long recovery times. Future research directions focus on lowering the operating temperature, improving selectivity, enhancing humidity tolerance, and developing nanostructured and surface-functionalized copper ferrite sensors. Furthermore, the integration of copper ferrite sensors into wearable and IoT devices, as well as field testing in real-world applications, presents exciting opportunities for expanding their use in environmental monitoring. This review highlights the current advancements in gas sensors and suggests potential strategies for overcoming existing limitations, paving the way for next-generation gas sensing technologies.

Nanostructured copper electrodes – a new step in the development of microbial bioelectrochemical systems

A simple-to-manufacture and inexpensive biosensor based on a nanostructured copper electrode, mediators and immobilized yeast or bacteria is proposed for determining the biochemical oxygen demand in wastewater.

Simulation of Plasmonic Effects in Nanostructured Copper Surfaces for Field-assisted Photoemission

Plasmonics in photoemission have recently gained interest due to their effect on important electron beam parameters such as emittance or quantum efficiency (QE), among others. For example, the presence of nanostructures at the surface of the photoemissive medium can increase the probability of electron emission if their morphological features match that of the plasmonic resonance when laser-irradiated in an electron gun. To determine the optimal size and geometry of these nanostructures and predict the resulting field enhancement, we conducted parametric electromagnetic simulations of nanostructured surfaces using COMSOL®. We investigated several types of geometries commonly found in laser processed copper substrates, optimized their performance under different irradiation wavelengths, and determined the expected maximal enhancement factor attainable.

Precision in cancer diagnostics: ultra-sensitive detection of MCF-7 breast cancer cells by gold nanostructure-enhanced electrochemical biosensing.

Timely identification of cancers is pivotal in optimizing treatment efficacy and reducing their widespread impact. This study introduces a novel biosensor for the sensitive electrochemical detection of cancer cells overexpressing mucin 1 (MUC1), a well-established model for breast cancer. The sensor substrate comprises gold columnar nanostructures obtained through glancing angle deposition (GLAD) of copper nanostructures, subsequently replaced by gold via a facile galvanic replacement process. Functionalizing these gold nanostructures with aptamers targeting the MUC1 glycoproteins, a prominent cancer biomarker, enables specific recognition of MCF-7 breast cancer cells. The proposed electrochemical sensing platform offers several advantages, including high selectivity, a wide linear range of detection, a low detection limit of 30 cells per mL, and long-term stability, rendering this sensor highly desirable for definitive breast cancer diagnosis.

Critical role of neem and jujube extracts in stabilizing copper nanostructures: A comparative study in green synthesis of CuNSs

Critical role of neem and jujube extracts in stabilizing copper nanostructures: A comparative study in green synthesis of CuNSs

(Invited) Application of Metal Oxide Active Supports for Enhancement of Electrocatalytic Reduction of Carbon Dioxide

Of particular interest to the preparation of advanced catalytic materials is efficient utilization of catalytic sites (metal and metal oxide nanostructures, their stabilization and intentional activation, as well as organization into two-dimensional arrays, ultra-thin films or three-dimensional networks (e.g. through sequential deposition) on electrode surfaces. They can form nanosized materials with well-defined composition, structure and thickness that exhibit desirable electrocatalytic properties (e.g. toward reduction of CO2). We explore here the ability of polynuclear inorganic metal oxo systems to stabilize and functionalize metal (e.g. copper) nanostructures. Here certain nanostructured metal oxides of zirconium, titanium, zinc or tungsten have been demonstrated to influence supported metal (e.g. Cu, Fe, Ag) centers in ways other than simple dispersion over electrode area. Evidence is presented that the support can modify activity (presumably electronic nature) of the above mentioned catalytic metal nanocenters thus affecting their chemisorptive and catalytic properties. Metal oxide cocatalysts can generate –OH groups at low potentials that induce proton mobility at the photo(electro)chemical interface.Our research interests concern development of systems for the electrocatalytic reduction of carbon dioxide not only in neutral but also in acid media. For example, nanosized Cu or Fe catalytic centers immobilized within ultra-thin films of tungsten oxide or mixed ZrO2-WO3 films have been considered and demonstrated to exhibit synergism during CO2-reduction. Selectivity of the catalytic systems largely depends on the activing adsorptive (CO2) phenomena and the affinity of catalytic centers to the adsorbed carbon monoxide (CO) type intermediates leading to their protonation or hydrogenation. Reduction of carbon dioxide begins now at less negative potentials and is accompanied by significant enhancement of the CO2-reduction current densities relative to the competitive hydrogen evolution. Among other important issues is the ability of certain metal oxides (e.g., WO3) to affect hydrogen via intra-structural sorption of hydrogen molecules or atoms.

The influence of reconstructive transformation from micro-/nanostructured copper(II) hydroxide to copper oxides as electrodes for high-performance supercapacitors

Copper(II) hydroxides, particularly Cu(OH)2 micro/nanostructures, are metastable under normal conditions. Notably, Cu(OH)2 micro-/nanostructures undergo structural restructuring and phase transitions during electrochemical reactions. In this study, the effects of electrolyte concentration, current, and duration of the electrochemical reaction on the crystal morphology, structure, and chemical composition of Cu(OH)2 micro-/nanostructured composite electrodes were investigated by anodic oxidation. The results showed that a Cu(OH)2 nanorod-like structure was formed on the electrode surface in the KOH electrolyte at a concentration of 3 M, while Cu2O crystals were synthesized at electrolyte concentrations of 1 M and 6 M. The growth current of the Cu(OH)2 nanorod-like structures ranged from 30 mA to 70 mA. At a reaction time of 10–80 min, the micro-/nanostructure of the electrode surface changed from an unstable Cu2O to a stable CuO phase through metastable Cu(OH)2. The synthesized Cu(OH)2 composite electrode exhibited an area-specific capacitance of 2777 mF cm–2 at a scanning rate of 10 mV s–1. In particular, the relationships between the surface morphology, structure, and chemical composition of the Cu(OH)2 composite electrode and the electrolyte concentration during cyclic voltammetry were studied. The results showed that in the KOH electrolyte at 1 M concentration, the Cu(OH)2 micro-/nanostructure transformed into Cu2O under electrochemical action, Cu(OH)2 transformed into both the Cu2O and CuO phases at 3 M electrolyte concentration, and Cu(OH)2 transformed into the CuO phase when the electrolyte concentration was increased to 6 M, indicating that the concentration of the alkaline electrolyte had a significant effect on the reconstruction and phase transformation of the Cu(OH)2 micro-/nanostructures. These results are expected to address the pressing issues in the application of metastable Cu(OH)2 micro/nanostructured composite electrodes in high-performance supercapacitors, such as insufficient energy, mass transfer, and structural instability.

Broad band optical absorption and thermoplasmonic response from bio-inspired hierarchical copper nanostructures fabricated by pulsed laser deposition

Broad band optical absorption and thermoplasmonic response from bio-inspired hierarchical copper nanostructures fabricated by pulsed laser deposition

Evaluation of physiochemical and electrochemical behaviour of reduced grapheme functionalized copper nanostructure as an effective corrosion inhibitor

This study examines the physicochemical properties and corrosion resistance of hydrothermally produced copper oxide-reduced graphene oxide nanocomposite (CuO/rGO). The CuO/rGO nanocomposite has a well-defined and homogeneous structure, decreased crystal size, and uniformly distributed CuO nanoparticles tethered to the rGO. X-Ray diffraction confirms the fabrication of 15.1 nm crystalline monoclinic CuO nanoparticles. EDX confirms the composite's composition by detecting Cu, O, and C components. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (LSV) tests evaluate the CuO/rGO nanocomposite's corrosion resistance. A mild steel plate under an HCl electrolyte with corrosion in the PPM ratio treats the nanocomposite-coated substrate. The composite's synergistic effect is assessed by comparing its corrosion performance to CuO/rGO concentrations in ppm. The corrosion resistance data demonstrate that the CuO/rGO composite improves with inhibitor concentrations of 0, 25, 50, 75, and 100 ppm. Adding rGO to the composite protects it and speeds up charge transfer, reducing corrosion and improving stability. The composite's synergistic effect of CuO and rGO provides excellent corrosion resistance regardless of concentration, making it a viable material for corrosion-prone applications. The research develops novel and effective anti-corrosion methods to preserve materials in the food, automotive, and large-scale energy industries.
 KEY WORDS: CuO/rGO nanocomposite, Tafel plot, Corrosion protection, Surface analysis
 Bull. Chem. Soc. Ethiop. 2024, 38(1), 269-280. DOI: https://dx.doi.org/10.4314/bcse.v38i1.20

Transition Metal Catalysts for Atmospheric Heavy Metal Removal: A Review of Current Innovations and Advances.

Atmospheric heavy metal pollution presents a severe threat to public health and environmental stability. Transition metal catalysts have emerged as a potent solution for the selective capture and removal of these pollutants. This review provides a comprehensive summary of current advancements in the field, emphasizing the efficiency and specificity of nanostructured transition metals, including manganese, iron, cobalt, nickel, copper, and zinc. Looking forward, we delve into the prospective trajectory of catalyst development, underscoring the need for materials with enhanced stability, regenerability, and environmental compatibility. We project that advancements in computational materials science, nanotechnology, and green chemistry will be pivotal in discovering innovative catalysts that are economically and environmentally sustainable. The integration of smart technologies for real-time monitoring and adaptive control is anticipated to revolutionize heavy metal remediation, ensuring efficient and responsive pollution abatement strategies in the face of evolving industrial scenarios and regulatory landscapes.

Creation of One- and Two-Dimensional Copper and Zinc Oxides Semiconductor Structures

The most effective methods for the synthesis of nanostructured copper and zinc oxides, which have unique properties and potential applications in a variety of fields including electronics, photonics, sensorics, and energy conversion, are analyzed. Special attention is paid to laser-based methods for synthesizing oxide nanostructures, with an emphasis on the importance of controlling power density distribution to influence the quality and properties of the nanomaterials. The great significance of wavefront shaping techniques for controlling laser-initiated processes is highlighted, which enable precise control over the phase and amplitude of light waves to achieve desired outcomes in optics and laser-assisted formation of one- and two-dimensional structures of oxide semiconductor materials. Diffractive computer optics is presented as a powerful tool for precise beam control. The significance of laser-induced thermochemical processes for creating and improving the properties of ZnO and CuO-based nanomaterials is discussed. The presented analysis shows that the synthesis of nanocomposites based on ZnO and CuO using pulse-periodic laser treatment, coupled with precise laser beam control using free-form diffractive optics, presents novel opportunities for applications in optoelectronics, sensor technology, electronics and portable energy sources manufacturing, and various other fields.

Nanostructure-induced inhibition of oxygen evolution and enhancement of methanol electrooxidation on engineered anodized brass

To capitalize the improved electrical contact feature, a self-supported hybrid binary/ternary copper and zinc oxides (i.e., ZnO–Cu2O and Cu2O–ZnO–CuO) nanostructures have been generated via a simple potentiostatic mode of anodaization on alpha brass in an alkaline medium. The catalyst nanostructuring i.e., wheat-grain-like to nanograss type structure has improved the mass transport, sluggish kinetics of methanol electrooxidation reaction process, and hindered the competitive oxygen evolution reaction (OER) of direct methanol fuel cell. The catalytic poisoning phenomenon has not been noticed due to two different reaction processes in two potential regions. Interestingly, a significant reduction in overpotential (η10mAcm−2OER−CH3OH) has been noticed for S125@A1 and S125@A2 samples i.e., 236 mV and 350 mV, respectively. The enhancement of current density has been explained through inductive circuit perspective. So, the present study provides a better insights to design and utilize non-precious metal/alloy based catalyst with hindered OER and enhanced methanol electrooxidation reaction activity.