Ag-Cu Nanoparticles Research Articles

Selective CO2 Reduction Electrocatalysis Using AgCu Nanoalloys Prepared by a "Host-Guest" Method.

Multimetallic nanoalloy catalysts have attracted considerable interest for enhancing the efficiency and selectivity of many electrochemically driven chemical processes. However, the preparation of homogeneous bimetallic alloy nanoparticles remains a challenge. Here, we present a room-temperature and scalable, host-guest approach for synthesis of dilute Cu in Ag alloy nanoparticles. In this approach, an ionic silver bromide precursor harboring exogenous Cu cations is reduced to yield ∼20 nm diameter AgCu alloy nanoparticles wherein the % Cu loading can be tuned precisely. AgCu nanoparticles with a 5% nominal loading of Cu exhibit peak activity (-0.23 mA/cm2 normalized partial current density) and selectivity (83.2% faradaic efficiency) for CO product formation from electrocatalytic reduction of CO2 at mild overpotentials. These AgCu nanoalloys exhibit a higher mass activity compared to Ag- and Cu-containing nanomaterials used for similar electrocatalytic transformations. Our host-guest synthesis platform holds promise for production of other nanoalloys with relevance in electrocatalysis and optics.

Evaluation effects of Biosynthesized copper-silver (Ag-Cu) nanoparticles from Ephedra intermedia plant extract on the apoptosis-related genes modulation and nitric oxide in MDA-MB-231 breast cancer cell line

Evaluation effects of Biosynthesized copper-silver (Ag-Cu) nanoparticles from <i>Ephedra intermedia</i> plant extract on the apoptosis-related genes modulation and nitric oxide in MDA-MB-231 breast cancer cell line

Nanosized-laser-induced sub-20 nm homogenous alloy nanoparticles

Alloy nanoparticles (NPs) have great potential in nanosized 3D-printing, surface coating, plasmonic enhancement, information coding, and so forth. However, chemical-pollution-free and homogeneous sub-20 nm NPs maintain still a challenge in preparation. Here we present a smart nanosecond laser scan strategy of alloy-NPs preparation on a bilayer metal film by using a nanosized focused beam, successfully realizing controllable fabrication of the sub-20 nm homogeneous alloy NPs without pollution. As a demonstration, various sub-20 nm AgCu NPs with different volume ratios have been prepared, all NPs show narrow size distribution and uniform interparticle spacing. This simple and cost-effective method is stable and adaptable for other alloy-NPs such as AuAg NPs. In addition, such alloy NPs exhibit two-peak plasma resonance feature and information coding capacity. We believe that homogenous alloy sub-20 nm NPs will provide new application opportunities in many fields.

Enhanced Antimicrobial Activity of AgCu Nanoparticles: The Role of Particle Size and Alloy Composition.

AgCu bimetallic· nanoparticles (NPs) represent a novel class of inorganic, broad-spectrum antimicrobial agents that offer enhanced antimicrobial effectiveness and reduced cytotoxicity compared to conventional Ag NP antibacterial materials. This study examines the antimicrobial performance and structural characteristics of AgCu nanoparticles (NPs) synthesized via two distinct chemical reduction processes using PVP-PVA as stabilizers. Despite identical chemical elements and sphere-like shapes in both synthesis methods, the resulting AgCu nanoparticles exhibited significant differences in size and antimicrobial properties. Notably, AgCu NPs with smaller average particle sizes demonstrated weaker antimicrobial activity, as assessed by the minimum inhibitory concentration (MIC) measurement, contrary to conventional expectations. However, larger average particle-sized AgCu NPs showed superior antimicrobial effectiveness. High-resolution transmission electron microscopy analysis revealed that nearly all larger particle-sized nanoparticles were AgCu nanoalloys. In contrast, the smaller particle-sized samples consisted of both AgCu alloys and monometallic Ag and Cu NPs. The fraction of Ag ions (relative to the total silver amount) in the larger AgCu NPs was found to be around 9%, compared to only 5% in that of the smaller AgCu NPs. This indicates that the AgCu alloy content significantly contributes to enhanced antibacterial efficacy, as a higher AgCu content results in the increased release of Ag ions. These findings suggest that the enhanced antimicrobial efficacy of AgCu NPs is primarily attributed to their chemical composition and phase structures, rather than the size of the nanoparticles.

Silver@copper-polyaniline nanotubes: Synthesis, characterization and biosensor analytical study

We introduce silver-copper nanoparticles incorporated into polyaniline (PANI) nanotubes using a straightforward and efficient reduction process. In this regard, PANI nanotubes with amine groups were fabricated through oxidation polymerization, followed by the attachment of Ag and Cu precursors to enable the synthesis of Ag-Cu bimetallic nanoparticles (NPs) on the pre-formed PANI nanotubes with the use of hydrazine as a reducing agent. The structural characterization of the synthesized NPs was investigated by UV–Vis spectrophotometer (UV–Vis), Dark-field emission, (EDX), X-ray diffraction (XRD) and field emission (FESEM), while the electrochemical properties were estimated by (CV) and differential pulse voltammetry (DPV). The findings indicated that the Ag-Cu NPs were present in the nanoscale range, well-dispersed, and attached to the surface of PANI nanotubes. Electrochemical investigations revealed that the Ag-Cu@PANI nanotube electrode demonstrated efficient electrooxidation of dopamine and hydroquinone without any interfering reactions, suggesting its potential use as an electrochemical biosensor for simultaneous detection of dopamine and hydroquinone. The proposed NPs-based biosensor was connected to concurrently identify dopamine and hydroquinone, illustrating moo distinguish Confinements of 0.46 µM for dopamine and 0.23 mM for hydroquinone, separately. Additionally, the manufactured sensor identified on a wide direct run the dopamine (5–25 µM), and hydroquinone (0.5–2.5 mM). Alongside these promising comes about, the Ag-Cu@PANI nanotube actualized great solidness and reproducibility, making it a favorable stage for electrochemical biosensing of dopamine and hydroquinone.

Regulating the surface morphology and improving the thermochromic properties of VO2 films by introducing Cu-Ag and Cu-Zr nanoparticles into the VO2/VO2/VO2 structure

Regulating the surface morphology and improving the thermochromic properties of VO2 films by introducing Cu-Ag and Cu-Zr nanoparticles into the VO2/VO2/VO2 structure

Enhanced photocatalytic activity in AgCu-decorated ZnO nanoparticles under UV and sunlight

This study investigates the structural, morphological, and photocatalytic properties of monometallic (Ag and Cu) and bimetallic (AgCu) nanoparticles (NPs) incorporated into ZnO NPs and their photocatalytic performance. X-ray diffraction and Rietveld refinement were employed to analyze the structural characteristics, revealing the formation of a hexagonal wurtzite structure of ZnO and cubic phases of Ag and Cu within the metal-decorated NPs. Scanning electron microscopy provided visual evidence of the spherical morphology, with an average particle size of 50 nm. Energy-dispersive X-ray spectroscopy confirmed the successful deposition of Ag, Cu, and AgCu NPs onto the ZnO surface. The photocatalytic efficiency of the NPs was evaluated by the degradation of methylene blue dye under UV light at a wavelength of 254 nm under sunlight irradiation. Under UV light, the bimetallic AgCu/ZnO system exhibited exceptional performance, achieving a degradation rate of about 95% with 10% AgCu/ZnO. Conversely, under sunlight illumination, the monometallic Cu/ZnO and Ag/ZnO NPs exhibited outstanding photocatalytic properties, with degradation rates of about 99 and 98%, respectively. These findings underscore the influence of the light source on photocatalytic performance as well as the significance of the plasmonic effects and charge-transfer mechanisms.

Preparation of Ag-Cu nanoparticle film using a dual-beam pulsed laser deposition for power electronic packaging

Ag-Cu nanoparticles, integrating the advantages of Ag and Cu, are promising materials for power electronic packaging. In this work, a novel dual-beam pulsed laser deposition method was proposed to prepare an Ag-Cu nanoparticle film with various component ratios and used for die attach at low temperatures. The as-deposited Ag-Cu nanoparticle film was mainly composed of Ag-Cu solid solution, Ag element, and Cu element, and most of the nanoparticles were in the alloying state. The Ag-Cu sintered joint presented a dense microstructure with 10.8% porosity, and the shear strength of Ag-Cu sintered joints could reach 60 MPa at 250 °C. The sintered joint porosity increased as more Cu were added in the Ag-Cu nanoparticle film, resulting in a decrease in the interfacial connection ratio. The fracture mode of sintered joints gradually changed from the sintered layer to the mixed sintered layer and interface fracture. The dual-beam pulsed laser deposition method could guide in designing the component ratios of bimetallic nanoparticles.

Broad-spectrum nano-bactericide utilizing antimicrobial peptides and bimetallic Cu-Ag nanoparticles anchored onto multiwalled carbon nanotubes for sustained protection against persistent bacterial pathogens in crops

Worldwide crop yields are threatened by persistent pathogenic bacteria that cause significant damage and jeopardize global food security. Chemical pesticides have shown limited effectiveness in protecting crops from severe yield loss. To address this obstacle, there is a growing need to develop environmentally friendly bactericides with broad-spectrum and sustained protection against persistent crop pathogens. Here, we present a method for preparing a nanocomposite that combines antimicrobial peptides (AMPs) and bimetallic Cu-Ag nanoparticles anchored onto multiwalled carbon nanotubes (MWCNTs). The nanocomposite exhibited dual antibacterial activity by disrupting bacterial cell membranes and splicing nucleic acids. By functionalizing MWCNTs with small AMPs (sAMPs), we achieved enhanced stability and penetration of the nanocomposite, and improved loading capacity of the Cu-Ag nanoparticles. The synthesized MWCNTs&CuNCs@AgNPs@P nanocomposites demonstrated broad-spectrum lethality against both Gram-positive and Gram-negative bacterial pathogens. Glasshouse pot trials confirmed the efficacy of the nanocomposites in protecting rice crops against bacterial leaf blight and tomato crops against bacterial wilt. These findings highlight the excellent antibacterial properties of the MWCNTs&CuNCs@AgNPs@P nanocomposite and its potential to replace chemical pesticides, offering significant advantages for agricultural applications.

Study of Structural and Optical Behaviour of Silver -Copper Bimetallic Nanoparticles

Silver-based nanomaterials have proven interesting and promising material for numerous applications such as biosensor, antimicrobial, anticancer agent, catalyst, food and water treatment, energy storage devices etc.In this study, nanoparticles of Silver and Copper were prepared by chemical reduction method, using hydrazine hydrate and Sodium borohydride as reducing agent. Fine powder of Ag-Cu nanoparticles (NPs)was obtained. The structural analysis of the sample wasdone using Powder XRD, SEM and TEM images and particle size analysis by DLS.The chemical purity and the elemental compositions of synthesized NPs were studied using SEM-EDX. Optical properties of the Ag-Cu NPs were analyzed using UV-DRS spectrum and FTIR spectrum. PXRD reveals that the NPs are highly crystalline in nature.The average crystallite size is30 nm. SEM and TEM images confirm the spherical morphology and the particle size is in nm. The DLS-particle size analyzer shows the size distribution of most of the NPs ranging from 9 nm to 100 nm. The EDX analysis reveals the percentage of elemental composition as 14.71, 9.06 and 76.23 for silver, copper and oxygen respectively. UV-DRS spectrum shows the absorption maximum occur at 371 nm. Due to the synergistic effect of silver and copper, there is blue shift in the absorption maximum. The IR spectrum discloses the metal oxide bond in the synthesized NPs.

Green and low-temperature synthesis of homogeneously alloyed AgCu nanoparticles supported on SiO2 for antibacterial and antifouling activities

AgCu alloy is attractive for various bio-applications; however, producing it at favorable temperatures remains challenging. This study introduces a green and cost-effective method using polyols for synthesizing homogeneously alloyed AgCu nanoparticles (NPs) supported on silica (AgCu-SiO2 nanocomposite) at low temperatures. Optimizing synthesis factors is discussed in detail. Through characterizations, the stable nanocomposite, in which homogeneously alloyed AgCu NPs were formed with an average size of 95.7 nm and uniformly attached to silica particles, can be obtained at 125 °C after a 45-min process. The excellent antibacterial activity of AgCu-SiO2 is evaluated (against Gram (-) Escherichia coli and Gram (+) Staphylococcus aureus bacteria) and compared with that of monometallic Ag-SiO2 and Cu-SiO2 nanocomposites. Besides, the antifouling application of AgCu-SiO2 used as paint is also demonstrated, revealing its protecting ability against marine environment corrosion within 180 days better than commercial paints. Overall, our homogeneously alloyed AgCu NPs supported on silica are a promising candidate for developing efficient and environmentally friendly antifouling agents due to the facile synthesis method, good antibacterial properties, and effective antifouling performance.

Intensifying heat using AgCu core-shell-based black titania with highly efficient photothermal conversion performance for solar-driven seawater desalination

A novel photoreceiver composed of black titania (BT) matrix with biochar for efficient steam production was investigated to measure the desalination efficiency under the illumination of one sun (1 kW m−2). The density of localized hotspots on the surface of the photothermal system is enhanced by the incorporation of AgCu core-shell that promotes photothermal activity and improves the degradation of methyl orange (MO) dye. Assemblages of AgCu nanoparticles on the surface of BT generated a strong stochastic plasmonic coupling and therefore broad-band absorption for much better solar energy consumption. The nanocomposite exhibited an excellent vaporization flux of 1.4 kg m−2 h−1 with high efficiency reaching 95.7 % under the illumination of one sun. AgCu@BT/BC exhibited an excellent surface temperature of 41 °C after only 5 min compared to other prepared photothermal systems. Furthermore, the prepared composites revealed superb degradation of MO dye under UV–vis light with a percentage of 96 %. The band gap energy of white titania decreased from 3.2 eV to 1.86 eV in the case of AgCu@BT/BC nanocomposite. Moreover, the crystalline AgCu@BT/BC demonstrates outstanding photocatalytic performance because of boosted charge migration, reduced electron-hole pair recombination rate, and identifiable shift to the red region.

Comparison of the resistivities of nanostructured films made from silver, copper-silver and copper nanoparticle and nanowire suspensions

Spray deposition and inkjet printing of various nanostructures are emerging complementary methods for creating conductive coatings on different substrates. In comparison to established deposition techniques like vacuum metal coating and lithography-based metallization processes, spray deposition and inkjet printing benefit from significantly simplified equipment. However, there are number of challenges related to peculiar properties and behaviour of nanostructures that require additional studies. In present work, we investigate electroconductive properties and sintering behaviour of thin films produced from nanostructures of different metals (Ag, Cu and Cu-Ag) and different shapes (nanowires and spherical nanoparticles), and compare them to the reference Ag and Cu magnetron deposited films. Synthesized nanostructures were studied with transmission electron microscopy. Morphology and crystallinity of produced metal films were studied with scanning electron microscopy and X-ray diffraction. The electrical parameters were measured by the van der Pauw method. All nanowires-based films provided high conductivity and required only modest thermal treatment (200 °C). To achieve sufficient sintering and conductivity of nanoparticles-based films, higher temperatures are required (300 °C for Ag nanoparticles and 350 °C for Cu and Cu-Ag nanoparticles). Additionally, stability of nanowires was studied by annealing the samples in vacuum conditions inside a scanning electron microscope at 500 °C.

Surface structured silver-copper bimetallic nanoparticles by irradiation of excimer laser pulses to bilayer thin films

Optical chips based on plasmonic bimetal nanoparticles are of particular interest for various applications, including optical sensors, as well as plasmon-enhanced fluorescence and plasmon-enhanced Raman scattering due to their extraordinary optical properties. In the paper, the formation of the bimetallic nanoparticles on the BK7 substrate and tuning of the LSPR wavelengths by irradiation of excimer laser pulses (193 nm output wavelength and 15 ns temporal pulse linewidth) to silver-copper thin films deposited by the physical vapor deposition (PVD) method is studied. Applying four and five ArF laser pulses with the fluence of 140 mJ cm−2 leads to the formation of spherical Ag-Cu nanoparticles and clusters, respectively, with several LSPR peaks in the UV and visible ranges. Also, sharp and intense LSPR peaks in the 560 to 700 nm spectral range are observed in the absorption spectra of the produced samples with four laser pulses which indicates the ability of the method for tuning the LSPR wavelength. Furthermore, the highest enhancement in the Raman scattering of R6G solution is provided using this sample as a substrate for Raman spectroscopy. Therefore, the laser-produced spherical Ag-Cu NPs by these parameters of laser irradiation can be a good candidate for applications based on LSPR, and Raman or fluorescence enhancement.

Plasma preparation of highly reactive Ag-Cu NPs anchored in N-PC as catalysts for Aluminum-air battery

Efficient, stable and economical catalysts play a crucial role in enhancing the kinetics of slow oxygen reduction reactions (ORR) in Aluminum-air batteries. Among the potential next-generation candidates, Ag catalysts are promising due to their high activity and low cost, but weaker oxygen adsorption has hindered industrialization. To address this bottleneck, Ag-alloying has emerged as a principal strategy. In this work, we successfully prepared Ag-Cu nanoparticles (NPs) with a rich eutectic phase and uniform dispersion structure using plasma evaporation. The increased solid solution of Ag and Cu led to changes in the electronic structure, resulting in an upward shift of the d-band center, which significantly improved oxygen adsorption. The combination of Ag and Cu in the NPs synergistically enhanced the adsorption of Ag and the desorption of Cu. Density functional theory (DFT) calculations revealed that Ag-Cu25 NPs exhibited the smallest limiting reaction barrier, leading to increased ORR activity. To further optimize the catalyst's performance, we utilized N-doped porous nanocarbon (N-PC) with high electrical conductivity and abundant mesoporous channels as the support for the Ag-Cu NPs. The N-PC support provided optimal mass transfer carriers for the highly active Ag-Cu25 NPs. As a result, the Ag-Cu25/NPC catalyst displayed excellent ORR activity in alkaline media, with a half-wave potential (E1/2) of 0.82 V. Furthermore, the Al-air battery incorporating the Ag-Cu25/NPC catalyst exhibited outstanding electrochemical performance. It demonstrated high open-circuit voltages of 1.89 V and remarkable power densities of 193 mW cm−2. The battery also sustained a high current output and maintained a stable high voltage for 120 hours under mechanical charging, showcasing its significant potential for practical applications.

The Enhanced Durability of AgCu Nanoparticle Coatings for Antibacterial Nonwoven Air Conditioner Filters.

Antibacterial nonwoven fabrics, incorporated with Ag, have been applied as masks and air conditioner filters to prevent the spread of disease from airborne respiratory pathogens. In this work, we present a comparison study of Ag ions: Ag and AgCu nanoparticles (NPs) coated onto nonwoven fabrics intended for use as air conditioner antibacterial filters. We illustrate their color changes and durability running in air conditioners using antibacterial activity testing and X-ray Photoelectron Spectroscopic (XPS) analysis. We found that AgCu NPs showed the best antibacterial efficacy and durability. XPS analysis indicated that the Ag concentration, on both the AgCu and Ag- NP-coated fibers, changed little. On the contrary, the Ag concentration on Ag ion-coated fibers decreased by ~30%, and the coated NPs aggregated over time. The color change in AgCu NP-coated fabric, from yellow to white, is caused by oxide shell formation over the NPs, with nearly 46% oxidized silver. Our results, both from antibacterial evaluation and wind blowing tests, indicate that AgCu NP-coated fibers have higher durability, while Ag ion-coated fibers have little durability in such applications. The enhanced durability of the AgCu NP-coated antibacterial fabrics can be attributed to stronger NP-fiber interactions and greater ion release.

Optimizing the Shape and Chemical Ordering of Nanoalloys with Specialized Walkers

AbstractNew algorithms for the optimization of alloy nanoparticles (nanoalloys) are presented. The new algorithms are based on the concept of multiple basin‐hopping walkers running in parallel, each with its own specialized task—the flying walker, exploring the energy landscape at high temperatures to sample different geometric structures, and the landing and hiking walkers mainly refining the optimization of chemical ordering at low temperatures. These algorithms are referred to as flying‐landing (FL) and flying‐landing‐hiking (FLH). The algorithms are tested against several benchmarks (AuCu and AuRh clusters of 400 atoms and PtNi clusters of 38 and 55 atoms). In all cases, both FL and FLH are shown to perform very well compared to previous results in the literature. In addition, the algorithms are applied to the optimization of larger AgCu nanoparticles, with sizes up to 4000 atoms, in order to establish the behavior of the mixing energy and to compare full global optimization of shape and chemical ordering with optimization of chemical ordering alone at a fixed shape. In general, the results show that the simultaneous optimization of shape and chemical ordering is necessary in many cases, and that the FLH approach is especially efficient for that purpose.

Ag-Cu Nanoparticles as Cathodic Catalysts for an Anion Exchange Membrane Fuel Cell

In this work, the synthesis of bimetallic Ag and Cu particles on carbon vulcan (AgCu/C) is reported, synthesized by a simple galvanic displacement method using citrate tribasic hydrate as a co-reducing agent and a commercial material based on Cu/C as a template. The materials were characterized by several physicochemical techniques, including TGA, ICP-OES, XRD, SEM, and BET. The catalysts were evaluated as cathodic catalysts for the oxygen reduction reaction (ORR) and were used for the preparation of membrane electrode assemblies for evaluation in an Anion Exchange Membrane Fuel Cell (AEMFC). The results were compared with the commercial Ag/C and Cu/C catalysts; the bimetallic catalyst obtained a higher power density, which was attributed to a synergistic effect between Ag and Cu particles.

Overview and Comparison of Physical and Chemical Methods to Produce Cu-Ag Nanoparticles

The present article deals with the overview of methods to produce Ag-Cu nanoparticles. Different chemical and physical procedures for the preparation of Ag-Cu nanoparticles are presented. A simple chemical reduction method is used to synthesise the colloidal mixture of bimetallic Ag-Cu nanoparticles. The Ag-Cu nanoparticles can be further characterised by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and UV–spectra. In physical techniques for the production of nanoparticles, laser ablation is used to produce Ag-Cu nanoparticles in alloy form. The analytical study can be done using characterisation techniques like SEM, HRTEM, SERS, and UV-visible spectroscopy.Keywords: Ag-Cu nanoparticles, XRD, Physical methods, Chemical methods, TEM, SEM.

Nitrogen-doped carbon confined Cu-Ag bimetals for efficient electroreduction of CO2 to high-order products

Electrochemical reduction of CO2 is a promising approach for storing the green electricity from intermittent solar and wind energy into chemical fuels. The direct production of energy-dense renewable synthetic fuels that is highly compatible with the existing transportation infrastructures is particularly important yet extraordinarily challenging. In this work, bimetallic Cu-Ag catalysts confined in a nitrogen-doped carbon octahedral shell are developed by a facile MOF-mediated synthesis for this grand objective. By correlative microscopic characterizations, theoretical and systematic experiments investigations, it is discovered that the bimetallic Cu-Ag nanoparticles work in synergy with the nitrogen-doped porous carbon octahedral shell for efficient electrocatalytic CO2 reduction reaction (CO2RR) towards high-order products. Owing to the geometric and electronic benefits, the as-designed electrocatalyst is favorable for C-C coupling through an interesting *CHO–*CO pathway with significantly lower energy barrier and enhanced mass transport of reactants and intermediates, thus leading to high activity and selectivity towards energy-dense products. The total faradaic efficiency of high-order products i.e., CH4, C2H4, C2H5OH and CH3COOH reaches 55.3% with a high current density of 5.3 mA/cm2 at a relatively low overpotential of −1.2 V versus reversible hydrogen electrode (RHE), exceeding the most common primary products e.g., H2, CO and HCOOH. This study presents that the rational assembly of Cu-derived bimetallic catalysts with confined nitrogen-doped carbon architecture to produce high-order products from electrocatalytic CO2 reduction.