Copper Silver Research Articles

Synthesis of copper-silver-zinc oxide nanocomposites for 4-nitrophenol reduction: doping and heterojunction.

The charge transfer and visible-light absorption capacities of stable materials are crucial in several applications, such as catalysis, absorption, sensors, and bioremediation. Copper-silver-zinc oxide nanocomposites (NCs) were synthesized using PVA as a capping agent and urea as a stabilizing agent. DTG analysis confirmed 500 °C was the optimum temperature for the total decomposition of PVA after capping the nanoparticles (NPs) to yield a pure composite. The XRD analysis showed the presence of copper inclusions in the ZnO lattice and the formation of Ag and CuO heterojunctions with ZnO. The photoluminescence (PL) analysis confirmed the more significant visible light absorption and charge transfer properties of the composite compared to those of single ZnO NPs. Foam-type porosity occurred during gas evolution at many of the points shown in the SEM/TEM images. Slight lattice fringe differences between the composite and ZnO NPs due to copper inclusion were confirmed from the HRTEM image and XRD pattern analysis. The crystallinity of the NPs and NCs was confirmed by the XRD pattern and SAED analysis. The diffusion-controlled charge transfer process was witnessed through CV electrochemical analysis. Thus, the energy- and time-efficient solution combustion synthesis (SCS) approach has a crucial future outlook, specifically for an industrial, scalable application. The NCs demonstrated more potential than ZnO NPs in an organic catalytic reduction reaction of 4-nitrophenol to 4-aminophenol.

High gradient off-axis coupled C-band Cu and CuAg accelerating structures

We report the high gradient testing results of two single-cell off-axis coupled standing wave accelerating structures. Two brazed standing wave off-axis coupled structures with the same geometry were tested: one made of pure copper (Cu) and one made of a copper–silver (CuAg) alloy with a silver concentration of 0.08%. A peak surface electric field of 450 MV/m was achieved in the CuAg structure for a klystron input power of 14.5 MW and a 1 μs pulse length, which was 25% higher than the peak surface electric field achieved in the Cu structure. The superb high gradient performance was achieved because of the two major optimizations in the cavity's geometry: (1) the shunt impedance of the cavity was maximized for a peak surface electric field to accelerating gradient ratio of ∼2 for a fully relativistic particle, and (2) the peak magnetic field enhancement due to the input coupler was minimized to limit pulse heating. These tests allow us to conclude that C-band accelerating structures can operate at peak fields similar to those at higher frequencies while providing a larger beam iris for improved beam transport.

Preparation of Conductive Screen-Printing Ink for High-Performance Bendable and Wearable ECG Electrodes on Fabric Substrates

Monitoring of vital signs is a necessary tool to diagnose the symptoms of illness. This work developed screen-printing inks for conductive nanomaterials to fabricate electrocardiogram (ECG)-compatible fabric electrodes. The contents of the polymer matrix, calcium carbonate additive filler, and conductive nanomaterials (silver nanoparticles and copper nanowires) on the resistivity of the composite inks were optimized. A facile process of screen printing was applied to fabricate the electrodes on fabric to create an efficient conductor with high stability in conduction. The fabricated electrodes exhibited flexible and bendable behavior over 0.7% bending strain for wearable components. The results showed that the fabricated electrode based on copper nanowires resistivity was 40.01 ± 1.94 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{k}\Omega $ </tex-math></inline-formula> /cm, and the proposed signal-to-noise ratio (SNR) was approximately 27.16 ± 9.37 dB. Therefore, these fabricated electrodes can be applied in wearable vital biosignal detection devices that perform with high sensitivity during movement, thereby providing health monitoring opportunities. Moreover, the fabricated electrodes can be used without excessive pressure or an electrolyte gel layer, thus overcoming the challenges of developing a portable device.

Highly Active Ag-Cu Nanocrystal Catalyst-Coated Brewer’s Spent Grain Biochar for the Mineralization of Methyl Orange and Methylene Blue Dye Mixture

The aim of the present work is to valorise the brewing industry’s waste, i.e., brewer’s spent grain (BSG), into functional biocarbon for environmental catalysis applications. In this context, cost-effective and environmentally friendly biochar support coated with in-situ-generated Ag-Cu nanocrystals, was developed via the wet impregnation of BSG biomass powder with copper (II) nitrate trihydrate and silver nitrate aqueous solution prior to pyrolysis at moderate temperature (500 °C). Small-size homogenously distributed Ag-Cu nanocrystals (≤80 nm) on the surface of the biochar (Biochar@Ag-Cu) were observed by field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM). Elemental compositions were determined by X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray analysis (EDX). The crystalline nature of the nanoparticles was confirmed by X-ray powder diffraction (XRD). Information about the thermal stability of the materials and quality were obtained by thermogravimetric analysis (TGA) and Raman, respectively. The potentiality of the Biochar@Ag-Cu catalyst in the field of pollutant removal is demonstrated by taking methyl orange and methylene blue as model dyes. A kinetics study was performed and analyzed by UV–vis spectroscopy. Its highly active catalytic nature is proved by the complete mineralization of the methyl orange dye (100%) through oxidative degradation. The reusability of the catalyst has shown 96% removal efficiency after 3 cycles. The linear plot of −Ln (CA/C0) vs. time (R2 = 0.9892) reveals that the mineralization of the methyl orange dye follows pseudo-first-order kinetics (k = 0.603 × 10−2 min−1). A methyl orange + methylene blue dye mixture degradation study has revealed the faster kinetics of the present catalyst towards methylene blue degradation. The current study suggests that BSG Biochar@Ag-Cu can be a potential candidate in contribution towards SDG 6.

Transportation of thermal and velocity slip factors on three-dimensional dual phase nanomaterials liquid flow towards an exponentially stretchable surface

The fundamental purpose of this research is to elaborate on slip boundary conditions and the flow of three-dimensional, stable, incompressible, rotating movements of nanoparticles lying across a stretchable sheet. The mathematical model for fluid flow is created using the assumptions stated above. The partial differentials are produced after utilizing boundary layer estimates. The partial differential governing equations are reduced into three coupled ordinary differential equations by using similarity transformations. After, applying transformations the system is solved numerically. Numerical results are approved with the help of the MATLAB bvp4c algorithm. The analysis shows that velocity and temperature are strongly dependent on essential parameters like stretching ratio, velocity slip, rotation, thermal slip parameter, and Prandtl number. Numerical values of distinct parameters on heat flux and skin friction factors are shown in a tabulated form. Partial velocity and thermal slip are applied to the temperature surface. The comparison among the nano-sized particles copper oxide and silver with water base nanofluid affecting velocity and temperature fields are used for analysis. Moreover, the Graphical depiction designates that the velocity and temperature spreading of the thermal slip parameter is increasing. It is observed that Ag-water is the best heat carrier as compared to CuO-water nanofluid.

Morphological, optical, and electrical properties of RF-sputtered zinc telluride thin films for electronic and optoelectronic applications

Zinc telluride (ZnTe) thin films were deposited by radio-frequency magnetron sputtering (RF-MS) onto optical glass coated by a silver–copper (Ag:Cu) thin film representing the back-electrode, and they were subsequently electrically contacted with an aluminum (Al) layer acting as the top-electrode. The RF-MS procedure was carried out at 50 W in argon (Ar) gas atmosphere kept at 2.5 × 10−3 mbar working pressure for 75 min at a substrate temperature of 220 °C kept constant during deposition. Morphological investigations by scanning electron microscopy allowed a first evaluation of the ZnTe film’s thickness. Optical characterization was then performed via absorption and transmission measurements in the spectral range between 300 and 1500 nm at room temperature. Subsequently, the thickness and bandgap energy of the ZnTe thin film were evaluated to be ∼508 nm and ∼2.13 eV, respectively. Moreover, they revealed high transmittance in infrared and near infrared regions of the electromagnetic spectrum. Then, the electrical measurements of Ag:Cu/ZnTe/Al “sandwich” structure (current–voltage characteristics) at six temperatures ranging from 303 to 354 K were performed, allowing the identification of the charge transport mechanisms through the structure along with their corresponding parameters. Based on the excellent optical and electrical properties, these ZnTe thin films show great potential as candidates for performant small-wavelength photodetectors.

Hierarchical assembled Ag2CuMnO4 nanoflakes as a novel electrode material for energy storage applications

In this work, a novel electrode material of hierarchical assembled silver copper manganese oxide (Ag2CuMnO4) nanoflakes was successfully prepared by a hydrothermal process at temperatures of 120 and 140 ºC. Influences of hydrothermal temperatures on the structure, morphology, porosities, and electrochemical performance of the prepared samples were thoroughly investigated. At 120 ºC, the flower-like microspheres composed of smaller Ag2CuMnO4 nanoflakes delivered the specific capacitance as high as 617.06 F g−1 at a current density of 1 A g−1 with the corresponding energy density of 145.17 Wh Kg−1. By using in-situ X-ray absorption near-edge structure (XANES) measurements, the charge storage mechanisms of Ag2CuMnO4 in 3 M KOH aqueous electrolyte were revealed for the first time through the multiple redox reactions of Ag/Ag1+, Cu/Cu1+, Cu1+/Cu2+, and Mn3+/Mn4+. For practical application, the symmetric supercapacitor device was fabricated by using Ag2CuMnO4 as both positive and negative electrodes. As a result, the fabricated supercapacitor device could deliver maximum energy density and power density of 2.40 Wh Kg−1 and 60.06 W Kg−1 at 0.1 A g−1, respectively. Therefore, this work provides some new insights into the charge storage mechanisms of Ag2CuMnO4 and its potential use as novel electrode material in supercapacitors.

Physical Interpretation of Nanofluid (Copper Oxide and Silver) with Slip and Mixed Convection Effects: Applications of Fractional Derivatives

A fractional model was developed for presenting the thermal assessment of nanoparticles in an inclined moving surface. Water was used as a base fluid, while the nanofluid utilized copper oxide and silver nanoparticles. The modification of the thermal model was further supported by mixed convection, magnetic force, and porous saturated space. Slip effects to the porous surface were also introduced. The fluctuation in temperature at different times was assumed by following the ramped thermal constraints. The fractional computations for the set of flow problems were performed with implementations of the Atangana–Baleanu (AB) and Caputo–Fabrizio (CF) analytical techniques. The integration process for such computations was achieved using the Laplace transformation. The comparative velocity and thermal analysis for the water and kerosene-oil-based nanofluid model is presented. The declining change in the velocity was observed due to the increase in the volume fraction of nanoparticles. It was observed that the increment in the temperature profile was more progressive for the kerosene oil and silver nanoparticle suspension.

Immobilization of biogenic silver–copper nanoparticles over arylated biochar from sugarcane bagasse: Method and catalytic performance

There is an ever‐growing demand for biochar production and its chemical transformation into specialty materials. Herein, we suggest a versatile method to elaborate Ag/Cu nanoparticles, by phytochemical process, on aryl‐sulfonated sugarcane bagasse pulp‐derived biochar. A binary nanocomposite has been fabricated through a four‐step strategy. The raw substrate biochar was first prepared by a slow pyrolysis of the biomass at 500°C under N2:H2 95%:5% inert atmosphere. Thereafter, in situ arylation of the biochar surface has been performed to obtain SO3H‐Biochar. The loading of silver and copper ions on SO3H‐Biochar has been achieved via a wet impregnation using a hydroalcoholic medium. Finally, the natural extract obtained from sugarcane bagasse has been employed to ensure the reduction of the adsorbed metal ions and obtain SO3H‐Biochar@Ag/Cu. Interestingly, the structural analysis of SO3H‐Biochar@Ag/Cu and the study of the evolution of D to G band intensity and area ratios have revealed that the metal phase deposition has altered the SO3H‐Biochar surface properties. It finally provided a more graphitized nanocomposite compared with the bare biochar and the intermediate substrate (SO3H‐Biochar). Such a result suggests that the phytochemical reduction has catalyzed the substrate graphitization. The catalytic performance of SO3H‐Biochar@Ag/Cu has been investigated in the oxidative degradation of malachite green oxalate. A total mineralization of the dye has been registered, and the experimental data were found to give a best fitting to the pseudo‐first‐order model. The fitting was relatively good with a mineralization apparent constant rate equals to 65 10−3 min−1. It is worth mentioning that all experiments used a relatively low amount of the composite catalyst (2.5 mg). So to recap, this route takes advantage of the two phases of sugarcane bagasse to generate a robust biochar‐based catalyst, its solid phase to derive biochar substrate with particular properties, and its liquid extract to be used as natural reducing preparation.

Quadratic and linear radiation impact on 3D convective hybrid nanofluid flow in a suspension of different temperature of waters: Transpiration and Fourier Fluxes

Recently, the word Hybrid is mostly used due to its high impact on various systems like medicinal manufacturing, automotive experimental designs, electrical designs of where heat transport is vital and naval equipment designs etc. The underlying intension of this study is to oversee flow and heat transmission on the three- dimensional boundary layer flow owing to the stretching along x−direction and y−direction of an incompressible ternary hybrid nanofluid through a rectangular closed domain is considered. Nanoparticles magnetite (Fe3O4) in spherical shape, copper (Cu) in cylindrical shape and silver (Ag) in platelet shape were considered along with water as base fluid. The proposed system is numerically solved with shooting procedure (R-K 4th order). Outcomes obtained for velocity along x-direction f′(ζ), velocity along y-direction g(ζ), and temperature distribution θ(ζ) are elucidated via the construction of graph. Comparative studies of obtained results with previously published results are discoursed with different compositions (Composition-I, Composition-II, and Composition-III). The Compsition-1 of mixture as magnetite (Fe3O4) in spherical shape, copper (Cu) in cylindrical shape and silver (Ag) in platelet shape with base water at 00c, Composition-II mixture as magnetite (Fe3O4) in spherical shape, copper (Cu) in cylindrical shape and silver (Ag) in platelet shape with base water at 100c and Composition-III mixture as magnetite (Fe3O4) in spherical shape, copper (Cu) in cylindrical shape and silver (Ag) in platelet shape with base water at 500c.The main outcome of this study is found to be - The important note is the friction factor is higher in normal water compared to water at 100c, water at500c.the heat transfer rate is more in quadratic thermal radiation case compared to linear radiation case. The significant note is intermediate temperature water at 100c is more equated to other two cases water at 500c and normal water.

Screen-Printable Cu–Ag Core–Shell Nanoparticle Paste for Reduced Silver Usage in Solar Cells: Particle Design, Paste Formulation, and Process Optimization

Copper–silver (Cu–Ag) core–shell nanoparticles are promising for replacing the silver particles and flakes used in printed conductors in current solar cells since they deliver good conductivity, chemical stability, and optical performance, while also reducing the silver content, thus significantly impacting the cost. The bare nanoparticles offer excellent air stability thanks to the silver-covered copper structure. We demonstrate a screen-printable paste for use in solar cell conductor applications. We report a printed morphology and light reflection properties similar to those achieved with commercial silver pastes. The reported Cu–Ag core–shell paste is uniquely formulated with an epoxy binder and an aliphatic hardener, delivering significantly improved electrical conductivity, while simultaneously reducing the overall silver content by ∼36 wt %. This is attributable to the cross-linked polymeric structure, low-temperature conversion, and improved loading of conductive core–shell nanoparticles. As needed for contact formation in conventional top-contact silicon solar cells, the paste is additionally loaded with lead bisilicate and delivers conductivity on par with that of commercial silver paste. Thus, by combining the reduction of the silver content with excellent electronic and optical properties, this Cu–Ag nanoparticle-based paste becomes attractive for low-cost printed-conductor applications, including photovoltaics and electronics.

Magnetic properties of transition metal ion-doped AgCuS: an ab-initio calculation

ABSTRACT Dilute magnetic semiconductor (DMS) is a trending research topic in material science for its requirements in spintronics technology in recent times. The present work reports the electrical and magnetic properties of different transition metal ions (Ti, V, Cr, Mn, Fe, Co, Ni and Zn)- doped silver copper sulphide. The dilute doping of transition metal ions at the copper site induces significant magnetic moments, which ordered ferromagnetically. The 3d orbital of the transition metal ions and the d orbital of Cu and Ag ions are the source of magnetisation.

Effect of Nickel, Tin, and Indium Doping of the Eutectic Silver–Copper Filler on the Capillary and Contact Processes in Brazing of Nonmetallic Alumina-Based Materials with Titanium

Effect of Nickel, Tin, and Indium Doping of the Eutectic Silver–Copper Filler on the Capillary and Contact Processes in Brazing of Nonmetallic Alumina-Based Materials with Titanium

Synthesis of Bimetallic Copper–Silver Nanoparticles in Solutions and on Polymeric Materials

Synthesis of Bimetallic Copper–Silver Nanoparticles in Solutions and on Polymeric Materials

Experimental study on the performance of pyramid solar still with novel convex and dish absorbers and wick materials

Solar still is a famous technique of the desalination methods, but it suffers from the low productivity. In this paper, novel structured convex absorbers were proposed in a pyramid solar still. The performance of the pyramid solar still (PSS) was experimentally investigated when using a convex cylinder absorber shape (CCPSS) and dish shape of absorber (CDPSS) instead of the flat absorber. The proposed absorber shapes increased the surface areas of exposure and evaporation and reduced the water depth to minimum inside the distiller. Also, the experimentations were conducted when using different heights of convex dish shape (5, 10, 15, and 20 cm) to obtain the optimum convex height of the dish absorber. Besides, the system was experimentally investigated when using two different wick materials of cotton cloth and jute wicks that were put over the convex surface. Furthermore, the performance of CDPSS was tested when painting the absorber by black paint mixed with different nanocomposites of titanium oxide (TiO2) copper oxide (CuO) and silver (Ag). Systems performance based on economic, enviroeconomic, CO2 reduction, and energy point of view was studied. Experimental results revealed that the CDPSS provided better performance than either CCPSS or PSS. Also, the optimum height of dish absorber that obtained the best performance of CDPSS was 15 cm, where at this height (15 cm), the increase in productivity of CDPSS was 54% with jute cloth over that of the PSS. The highest productivity of CDPSS was obtained when using Ag followed by CuO and then TiO2, where the average daily productivity of CDPSS with jute and Ag was 6750 mL/m2.day compared to 3800 mL/m2.day for that of PSS (improvement = 78% and efficiency = 45.7%). Besides, the rate of CO2 mitigation for the CDPSS with Ag, CuO, TiO2 and without nanoparticles was about 13.5, 12.7, 12.5, 10.17 tons/y respectively. Also, the enviroeconomic parameter (Z^') was 147.6, 181.2, 184.1, and 195.1 per year for the (CDPSS), (CDPSS + TiO2), (CDPSS + CuO), and (CDPSS + Ag), respectively for 365 operating days and lifetime 20 years. Finally, the costs of the distilled water of PSS and CDPSS with jute cloth and silver nanoparticles were 0.018 and 0.015 $/L, respectively.

Selective Electroless Copper Plating of Ink-Jet Printed Textiles Using a Copper-Silver Nanoparticle Catalyst.

The electroless copper plating of textiles, which have been previously printed with a catalyst, is a promising method to selectively metallise them to produce high-reliability e-textiles, sensors and wearable electronics with wide-ranging applications in high-value sectors such as healthcare, sport, and the military. In this study, polyester textiles were ink-jet printed using differing numbers of printing cycles and printing directions with a functionalised copper–silver nanoparticle catalyst, followed by electroless copper plating. The catalyst was characterised using Transmission Electron Microscopy (TEM) and Ultraviolet/Visible (UV/Vis) spectroscopy. The electroless copper coatings were characterised by copper mass gain, visual appearance and electrical resistance in addition to their morphology and the plating coverage of the fibres using Scanning Electron Microscopy (SEM). Stiffness, laundering durability and colour fastness of the textiles were also analysed using a stiffness tester and Launder Ometer, respectively. The results indicated that in order to provide a metallised pattern with the desired conductivity, stiffness and laundering durability for e-textiles, the printing design, printing direction and the number of printing cycles of the catalyst should be carefully optimised considering the textile’s structure. Achieving a highly conductive complete copper coating, together with an almost identical and sufficiently low stiffness on both sides of the textile can be considered as useful indicators to judge the suitability of the process.

Relativistic Effects Stabilize Unusual Gold(II) Sulfate Structure via Aurophilic Interactions.

The crystal structure of gold(II) sulfate is strikingly different from other coinage metal(II) sulfates. Central to the unsual AuSO4 bulk structure is the Au24+ ion with a very close Au-Au contact, which is a structural feature that does not appear in CuSO4 and AgSO4. To shed some light on this unusual behavior, we decided to investigate the relative stabilities of the coinage metal(II) sulfates utilizing periodic Density Functional Theory. By computing relative energies of the hypothetical nonrelativistic gold(II) sulfate (AuNRSO4) in different structural arrangements and performing chemical bonding analyses employing the Electron Localization Function as well as the Quantum Theory of Atoms in Molecules method, we show that the stability of the unsual AuSO4 bulk structure can be related to aurophilic interactions enabled by relativistic effects. From the relative stabilities and UV-vis spectra computed via GW methodology, we predict that AuNRSO4 would assume the structure of either copper(II) sulfate or silver(II) sulfate with almost equal likelihood and appear as bright-violet or deep-blue substances, respectively.

Improving thermal conductivity of Inconel 718 through thermoelectric coupling to reduce cutting temperature

Inconel 718 is hard to machine with higher cutting temperature generated during machining process due to its low thermal conductivity. The thermal conductivity of materials consists of phonon and electronic thermal conductivity. The increase of electrical conductivity of material will improve its electronic thermal conductivity based on the Wiedemann–Franz law. A novel surface conductive active medium (SCAM) coating method is proposed. The SCAM is coated on the surface of Inconel 718 to be machined to decrease tool cutting temperature. The composition of electronic and phonon thermal conductivity of Inconel 718 is inspected by four-probe experiments. Two SCAMs including copper conductive adhesive (1.7 × 106 S m) and silver conductive adhesive (3.3 × 106 S m) are sampled in this research. The effect of SCAMs on improving the thermal conductivity of Inconel 718 is analyzed based on the serial electrical conductivity theoretical model. The maximum temperature of cutting tool during orthogonal cutting experiment decreases with the increase of SCAM electrical conductivity, which is agreed with the cutting temperature distribution predicted by theoretical calculations. It is demonstrated that the cutting tool temperatures can be reduced by improving thermal conductivity of Inconel 718 through coating surface conductive active mediums with high electrical conductivity.

Stochastic structure of metal prices: Evidence from fractional integration non-linearities and breaks

This paper investigates the long memory properties of the prices series of two major precious metals (gold and silver) and six non-precious metals (aluminium, copper, lead, zinc, tin and nickel) by using a fractional integration modelling framework, while controlling for structural breaks and non-linearities. We use daily data in a range from November 01, 2007 to March 20, 2020. From the results, Copper and Tin exhibit a very small degree of mean reversion. However, if autocorrelation is permitted, the unit root null hypothesis cannot be rejected in any of the series. We also account for structural breaks and non-linearities. We observe that all the series under investigation are exposed to multiple breaks. Results obtained under white noise errors shows some evidence of mean reversion for silver aluminium, copper, tin and zinc in some of the subsamples. However, under the assumption of Bloomfield autocorrelated errors the confidence intervals are so wide that we cannot confirm this evidence in any single case.

Mechanistic study of copper oxide, zinc oxide, cadmium oxide, and silver nanoparticles-mediated toxicity on the probiotic Lactobacillus reuteri

The use of metal/metal oxide nanoparticles (NPs) in consumer products has increased dramatically. Accordingly, human exposure to these NPs has increased. Lactobacillus reuteri, a member of the beneficial gut microbiota, is essential for human health. In the present study, the toxic effect of three metal oxides (CuO, ZnO, and CdO) and one metal (Ag) NPs on L. reuteri were investigated in vitro. L. reuteri was susceptible to all the prepared NPs in a dose-dependent manner, visualized as an increase in the zones of inhibition and a significant reduction in the maximum specific growth rates (µ max). The minimal inhibitory concentrations were 5.8, 26, 560, and 560 µg/mL for CdO-, Ag-, ZnO-, and CuO-NPs, respectively, and the respective minimal bactericidal concentrations were 60, 70, 1500, and 1500 µg/mL. Electron microscopic examinations revealed the adsorption of the prepared NPs on L. reuteri cell surface, causing cell wall disruption and morphological changes. These changes were accompanied by significant leakage of cellular protein content by 214%, 191%, 112%, and 101% versus the untreated control when L. reuteri was treated with CdO-, Ag-, CuO-, and ZnO-NPs, respectively. NPs also induced oxidative damage, where the malondialdehyde level was significantly increased, and glutathione content was significantly decreased. Quantifying the DNA damage using comet assay showed that CuONPs had the maximum DNA tail length (8.2 px vs. 2.1 px for the control). While CdONPs showed the maximum percentage of DNA in tail (15.5% vs. 3.1%). This study provides a mechanistic evaluation of the NPs-mediated toxicity to a beneficial microorganism.