Ag-Cu Bimetallic Nanoparticles Research Articles

Synthesis of Composition-Tunable Ag-Cu Bimetallic Nanoparticles Through Plasma-Driven Solution Electrolysis.

Bimetallic nanomaterials have shown great potential across various fields of application. However, the synthesis of many bimetallic particles can be challenging due to the immiscibility of their constituent metals. In this study, we present a synthetic strategy to produce compositionally tunable silver-copper (Ag-Cu) bimetallic nanoparticles using plasma-driven liquid surface chemistry. By using a low-pressure nonthermal radiofrequency (RF) plasma that interacts with an Ag-Cu precursor solution at varying electrode distances, we identified that the reduction of Ag and Cu salts is governed by two "orthogonal" parameters. The reduction of Cu2+ is primarily influenced by plasma electrons, whereas UV photons play a key role in the reduction of Ag+. Consequently, by adjusting the electrode distance and the precursor ratios in the plasma-liquid system, we could control the composition of Ag-Cu bimetallic nanoparticles over a wide range.

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.

Argyreia nervosa-driven biosynthesis of Cu-Ag bimetallic nanoparticles from plant leaves extract unveils enhanced antibacterial properties.

Our study specifically explores the biosynthesis of copper-silver bimetallic nanoparticles (Cu-Ag BMNPs) using Argyreia nervosa (AN) plant leaf green extract as a versatile agent for capping, reducing, and stabilizing. This biosynthesis method is characterized by its simplicity and cost-effectiveness, utilizing silver nitrate (AgNO3) and cupric oxide (CuO) as precursor materials. Our comprehensive characterization of the Cu-Ag BMNPs, employing techniques such as X-ray diffraction (XRD), UV-Vis spectrometry, scanning electron microscopy (SEM), Zetasizer, and Fourier transformed infrared spectrometry (FTIR). FTIR analysis reveals biofunctional groups and chemical bands, while SEM and XRD analyses provide morphological and structural details. To evaluate the antimicrobial properties of the Cu-Ag BMNPs, we conducted disc diffusion and minimum inhibitory concentration (MIC) assays against Escherichia coli (E. coli), with results compared to the standard gentamicin antibiotic. It is observed that the 2% and 5% CuO concentrations of AN Cu-Ag BMNPs exhibit substantial antibacterial activity in comparison to AN extract when tested on EPEC. Among these, the Cu-Ag BMNPs at a 2% concentration demonstrate higher antibacterial activity, potentially attributed to the enhanced dispersion of BMNPs facilitated by the lower CuO doping concentration. These two assays showcased the improved antimicrobial activity of Cu-Ag BMNPs, highlighting their synergistic effect, characterized by high MIC values and a broad zone of inhibition in the disc diffusion tests against E. coli. These results emphasize the significant antibacterial potential of the synthesized BMNPs, with a medicinal plant AN leaf extract playing a pivotal role in enhancing antibacterial activity.

An investigation of photocatalytic and biological properties of Croton bonplandianum-mediated Ag-Cu bimetallic nanoparticles

The green synthesis of nanoparticles using plant parts and their essence is considered an archetypal tactic in material synthesis for environmental beneficence. Multitudinous metal nanoparticles with potential bioactivities have been prepared based on plant extract. This study's main objective is synthesizing Ag-Cu bimetallic nanoparticles (Ag-Cu BMNPs) using leaf extract of Croton bonplandianum L (CB). Furthermore, its photocatalytic, antibacterial, anti-fungal, and anti-tuberculosis activities are systematically investigated in detail. The surface morphology of the prepared sample is shown to be highly porous, with an average grain size of ∼ 16 nm. The FTIR spectra exhibited that the phytomolecules from CB leaf extract serve as a capping and reductantfor forming Ag-Cu BMNP. Brunauer-Emmitte-Teller (BET) comprehends the CB leaf extract to be an active, cost-effective, reusable, and high surface area catalyst. The sample exhibited improved photocatalytic activity with an efficiency of 92.31 % at the moderate catalyst dose of 30 mg against methylene blue (MB) dye. Ag-Cu BMNPs exhibited a 17 mm inhibition zone at higher concentrations against both gram (+ve) and gram (−ve) bacterial strains. Also, the synthesized Ag-Cu BMNPs produced a clear inhibition zone of 16 mm and 15 mm at lower concentrations. The anti-fungal activity against A. flavus and C. albicans at higher and lower concentrations produced a clear inhibition zone of 17 mm,15 mm, and 6 mm, 9 mm, respectively. In addition, the anti-tuberculosis activity against Mycobacteria tuberculosis exhibited good results at a 0.4 µg/mL concentration for the synthesized sample. Moreover, Ag-Cu BMNPs enhanced their biological ability and did not increase their cytotoxicity, which provides a potential for the clinical applications of Ag-Cu BMNPs. In general, the suggested method for producing Ag-Cu bimetallic nanoparticles is successful in combating microbiological diseases.

Cu-Ag bimetallic nano-catalyst anchored on polyvinyl alcohol sponge for catalytic reduction of 4-nitrophenol

With increasing interest and demand for treating organic wastewater, fabricating a heterogeneous catalyst combining low-cost, excellent catalytic efficiency, and good recyclability is necessary but remains challenging. In this work, we developed a kind of low-cost Cu-Ag bimetallic nano-catalyst anchored on polyvinyl alcohol sponge (Cu-Ag/PVA) via step impregnation and reduction method, which demonstrated excellent catalytic efficiency and good recyclability for the reduction of the organic pollutant 4-nitrophenol (4-NP). The compositional and microstructural results confirmed that Cu-Ag bimetallic nanoparticles with an average size of tens of nanometers were uniformly anchored on the porous PVA sponge. The catalytic results showed that the prepared Cu-Ag/PVA exhibited an appealing catalytic performance and recyclability compared with monometallic Cu or Ag nano-catalyst, which is ascribed to the reason that bimetallic Cu-Ag has lower binding energy and is easier to transfer electrons in the catalytic reduction of 4-NP compared to monometallic catalyst. The optimal kinetic catalytic rate constants for Cu-Ag/PVA is 0.54 min−1, and the conversion of 4-NP maintained above 98% after twelve consecutive catalytic cycles. Therefore, this inexpensive, efficient, and recyclable Cu-Ag/PVA catalyst has potential application in organic wastewater treatment.

Effect of Gum acacia capped Cu-Ag bimetallic nanoparticles on germination and growth of gram seeds (Cicer arietinum L.)

Gum acacia (GA) capped Cu-Ag bimetallic nanoparticles (Cu/Ag@GA2) have been synthesized by hydrazine hydrate assisted co-reduction of copper sulphate and silver nitrate. Cu/Ag@GA2 was extensively characterized using UV–Vis, FT-IR, FE-SEM, EDX, HR-TEM, and XRD analyses. The formation of Cu/Ag@GA2 was evidenced by SPR absorption peaks at 425 nm and 620 nm. SEM picture revealed that Cu/Ag@GA2 has a porous network structure decorated with small needle-shaped bud-like structures while the TEM study revealed an average particle size of ∼ 8 nm. Cu/Ag@GA2 exhibited a good shelf life and could be stored for > 140 days with full activity. The germination and growth of Cicer arietinum L. were studied under the influence of Cu/Ag@GA2 suspension. The presence of Cu/Ag@GA2 positively affected the germination and growth of gram seeds. The optimum concentration of Cu/Ag@GA2 was 200 mg/L. Above this concentration, the toxic levels were reached and a decline in the growth was witnessed. Cu/Ag@GA2 (200 mg/L) and distilled water treated seeds exhibited 85 % and 22 % germination respectively while the number of leaves, roots, shoot, and total length after 14 days of treatment were 85, 9.2 cm, 30.2 cm, and 39.4 cm respectively as compared to 45, 3.8 cm, 15 cm, 18.8 cm for the plants grown in distilled water. Thus Cu/Ag@GA2 may find use as an effective nanofertilizer for Cicer arietinum L. plant.

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.

Biosynthesis, Characterization and Photocatalytic Activities of Ag-Cu Bimetallic Nanoparticles Derived from mukia maderaspatana Leaf Extract

Abstract: The majority of studies focused on the biological synthesis of nanoparticles, which was one of the unexpansive methods. Utilizing mukia maderaspatana Leaf extract, we have focused on the Cheapest and simplest method for the synthesis of Ag-Cu bimetallic Nanoparticles. The synthesized Ag-Cu BNPs were further confirmed by UV-visible spectroscopy, FT-IR spectroscopy, Scanning electron microscope (SEM) and Energy dispersive X-ray spectroscopy (EDX). Further we also discuss the Photocatalytic absorption of Amido Black dye processed in UV irradiation at various time interval. This Biosynthetic method has been discovered to be economical, environmentally benign and promising for use in a variety of fields.

Bimetallic AgCu nanoparticles decorated on zeolitic imidazolate framework derived carbon: An extraordinarily active and recyclable nanocomposite catalyst for reduction of nitroarenes and degradation of organic dyes

Zeolitic imidazolate framework-8 (ZIF-8) derived carbon (CZ-8) is explored as support to immobilize bimetallic AgCu nanoparticles (NPs) (denoted as AgCu@CZ-8) for the first time to be used as catalyst for reduction of nitroarenes and degradation of toxic dyes. A series of AgCu@CZ-8 with different Ag/Cu ratios is prepared by simultaneous chemical reduction of silver and copper nitrates in the presence of two reducing agents, i.e., NaBH4 and NH3BH3. Due to high surface area, presence of N atoms in the framework, modified electronic structure of AgCu caused by alloy formation and synergistic effects, the catalytic activities of bimetallic AgCu@CZ-8 nanocomposites are much higher than monometallic counterparts Ag@CZ-8 and Cu@CZ-8 for reduction of 4-nitrophenol (4-NP), and degradation of methyl orange (MO) and rhodamine B (RhB). Ag6Cu4 @CZ-8 exhibits a superb reaction rate of 12.93 min-1 and outstanding activity of 581880 min-1gcat-1 for reduction of 4-NP to 4-aminophenol (4-AP). On the other hand, Ag2Cu8 @CZ-8 delivers outstanding rate constants of 12.9 and 20.73 min-1 for degradations of MO and RhB, respectively. The catalyst shows excellent stability and recyclability after reuse for 5 cycles. The results presented here demonstrate that the carbonized ZIF-8 can provide a unique platform for the growth of uniformly dispersed bimetallic NPs with high catalytic activity towards various catalytic reactions.

Biosynthesis of Novel Ag-Cu Bimetallic Nanoparticles from Leaf Extract of Salvia officinalis and Their Antibacterial Activity.

Bimetallic nanoparticles exhibit bifunctional or synergistic effects prevailing between two metals with the capabilities of enhanced electronic, catalytic, and optical properties. Green synthetic routes have gained tremendous interest because of the noninvolvement of toxic and harmful chemical reagents in preparation. Therefore, we develop bimetallic Ag-Cu nanoparticles (Ag-Cu NPs) through an eco-friendly and biocompatible preparation method. In this study, Ag-Cu NPs have been synthesized from leaf extracts of the commonly known sage, S. officinalis. The extract has a rich phytochemical composition, including bioreducing polyphenols, flavonoids, and capping/stabilizing agents. An array of well-known spectroscopic and microscopic techniques were used to characterize the as-prepared Ag-Cu bimetallic nanoparticles, including X-ray diffraction (XRD), ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The size of the Ag-Cu NPs was found to be 50 nm with a spherical shape and an almost uniform distribution. The antibacterial effect was further evaluated using agar well diffusion and disc diffusion assays. Ag-Cu NPs exhibit antibacterial and antibiofilm properties against Gram-positive and Gram-negative bacteria strains. The minimum inhibitory concentration (MIC) of Ag-Cu NPs was between 5 g/mL and 15 g/mL. The Ag-Cu NPs inhibit biofilm formation at 25 g/mL and 50 g/mL. The results of biogenic Ag-Cu NPs provide novel antibacterial activity against Gram-positive and Gram-negative bacteria, as well as antibiofilm activity. Hence, Ag-Cu NPs might serve as a novel antibacterial agent with potential antibacterial and antibiofilm properties.

Regulating surface morphology and thermochromic properties of VO2 films by Cu-Ag bimetallic nanoparticles

For decades, the synchronous improvements of solar modulation ability (ΔTsol) and luminous transmittance (Tlum) has always been a challenge for VO2-based smart windows. In this research, Cu-Ag bimetallic nanoparticles (Cu-Ag NPs) were embedded into VO2/VO2 bilayer films by pulsed laser deposition. The effects of Cu-Ag NPs on crystal quality, surface morphology and optical properties of VO2 film were investigated. The results showed that the intensity of localized surface plasmon resonance (LSPR) effect could be adjusted by changing the number of laser pulses during Cu-Ag NPs deposition process. SEM and EDS characterization further suggested that Cu-Ag NPs preferred to nucleate at the "concave" formed by several VO2 grains. Compared with VO2/VO2 bilayer film (ΔTsol = 8.1%, Tlum = 40.0%), VO2/Cu-Ag NPs/VO2 composite film showed excellent energy saving performance, the ΔTsol and Tlum were further improved to 10.6% and 55.7%, respectively. In addition, the finite-difference time-domain simulations revealed that the improvements of thermochromic properties could be attributed to the LSPR effect induced by the unevenly distributed VO2 nanoparticles. The results in this work confirmed that the existence of the irregular Cu-Ag NPs could both improve the crystallinity and regulate the grain shape of VO2 films, which is an effective way to enhance the performance of VO2 smart windows.

Fabrication of Bimetallic Cu-Ag Nanoparticle-Decorated Poly(cyclotriphosphazene-co-4,4'-sulfonyldiphenol) and Its Enhanced Catalytic Activity for the Reduction of 4-Nitrophenol.

We reported a study on the preparation of bimetallic Ag–Cu nanoparticles (NPs) impregnated on PZS poly(cyclotriphosphazene-co-4,4′-sulfonyldiphenol) nanotubes via a facile and efficient reduction method. Herein, PZS nanotubes consisting of enriched hydroxyl groups are fabricated through an in situ template method, and then, fluctuating the amount ratios of Cu and Ag precursors, bimetallic NPs can be fabricated on readily prepared PZS nanotubes using NaBH4 as a reductant, which results in a series of bimetallic catalysts having tunable catalytic activity. The characterization investigations of scanning electron microscopy, X-ray diffraction, transmission electron microscopy, and Fourier transform infrared spectroscopy results show that Ag–Cu bimetallic NPs are well-dispersed, ultrasmall in size, and well-anchored on the surface of PZS nanotubes. In addition, to examine the catalytic activity and reusability of these nanocomposites, reduction of 4-nitrophenol to 4-aminophenol is utilized as a prototype reaction. The optimized Ag–Cu NPs with a copper ratio of 0.3% are well-stabilized by the organic–inorganic poly(cyclotriphosphazene-co-4,4′-sulfonyldiphenol) nanotubes. The obtained results show that bimetallic NPs have remarkably higher catalytic ability than that of their monometallic counterparts with maximum catalytic activity. These results are even better than those of noble metal-based bimetallic catalysts and pave the avenue to utilize the polyphosphazene polymer as a substrate material for highly effective bimetallic catalysts.

Optimization of the Synthesis of Fungus-Mediated Bi-Metallic Ag-Cu Nanoparticles

Bi-metallic nanoparticles (NPs) have appeared to be more efficient as antimicrobials than mono-metallic NPs. The fungus Aspergillus terreus-mediated synthesis of bi-metallic Ag-Cu NPs was optimized using response surface methodology (RSM) to reach the maximum yield of NPs. The optimal conditions were validated using ANOVA. The optimal conditions were 1.5 mM total metal (Ag + Cu) concentration, 1.25 mg fungal biomass, 350 W microwave power, and 15 min reaction time. The structure and shape of the synthesized NPs (mostly 20–30 nm) were characterized using several analytical tools. The biological activities of the synthesized NPs were assessed by studying their antioxidant, antibacterial, and cytotoxic activity in different NP concentrations. A dose-dependent response was observed in each test. Bi-metallic Ag-Cu NPs inhibited three clinically relevant human pathogens: Klebsiella pneumoniae, Enterobacter cloacae, and Pseudomonas aeruginosa. Escherichia coli, Enterococcus faecalis, and Staphylococcus aureus were inhibited less. The DPPH and hydrogen peroxide scavenging activities of the NPs were high, reaching 90% scavenging. Ag-Cu NPs could be studied as antimicrobials in different applications. The optimization procedure using statistical analyses was successful in improving the yield of nanoparticles.

Enhanced green mediated synthesis of optimized Ag-Cu bimetallic nanoparticles using Leucas aspera and its application in Anti-cancer activity against alveolar cancer

Silver-copper bimetallic nanoparticles (Ag-Cu BNP) were synthesized from the leaf extract of Leucas aspera as a bio-reducing agent and optimized through the Box-Behnken Design (BBD) statistical optimization tool. Optimized conditions for Ag-Cu BNP synthesis were found that silver nitrate (0.75 g/L), copper acetate (0.3 g/L), plant extract (0.2 g/L) and pH (5) showed maximal absorption unit of 4.2 at 292 nm owing to the high yield of Ag-Cu BNP. Biosynthesized Ag-Cu BNP showed characteristic UV–visible spectra, FTIR Spectra and XRD patterns owing to its highly crystalline, tetragonal, smooth-surfaced spherical structures. Size of BNP was confirmed to be 20 nm by TEM analysis. EDX result spectra confirm the presence of silver and copper elements in Ag-Cu BNP preparation. In vitro Ag-Cu BNP showed significant alveolar anti-cancer and antioxidant activity against human alveolar cancer cell line A549 than aqueous leaf extract of Leucas aspera with IC 50 values 62 µg/ml and 33.72 µg/ml respectively.

Beta vulgaris Assisted Fabrication of Novel Ag-Cu Bimetallic Nanoparticles for Growth Inhibition and Virulence in Candida albicans.

Beta vulgaris extract contains water-soluble red pigment betanin and is used as a food colorant. In this study, the biogenic Ag-Cu bimetallic nanoparticles were synthesized and characterized by different spectroscopic and microscopic techniques, including UV–Visible, FTIR, TEM. SEM-EDX, XRD, and TGA. Further, Ag-Cu bimetallic nanoparticles capped with Beta vulgaris biomolecules were evaluated for their antifungal activity against Candida albicans via targeting its major virulence factors, including adherence, yeast to hyphae transition, extracellular enzyme secretion, biofilm formation, and the expression of genes related to these pathogenic traits by using standard methods. C. albicans is an opportunistic human fungal pathogen that causes significant morbidity and mortality, mainly in immunocompromised patients. The current antifungal therapy is limited with various shortcomings such as host toxicity and developing multidrug resistance. Therefore, the development of novel antifungal agents is urgently required. Furthermore, NPs were screened for cell viability and cytotoxicity effect. Antifungal susceptibility testing showed potent antifungal activity of the Ag-Cu bimetallic NPs with a significant inhibitory effect on adherence, yeast to hyphae transition, extracellular enzymes secretion, and formation of biofilms in C. albicans at sub-inhibitory and inhibitory concentrations. The RT-qPCR results at an MIC value of the NPs exhibited a varying degree of downregulation in expression levels of virulence genes. Results also revealed the dose-dependent effect of NPs on cellular viability (up to 100%) using MUSE cell analyzer. Moreover, the low cytotoxicity effect of bimetallic NPs has been observed using haemolytic assay. The overall results indicated that the newly synthesized Ag-Cu bimetallic NPs capped with Beta vulgaris are proven to possess a potent anticandidal activity, by affecting the vital pathogenic factors of C. albicans.

CuAg and AuAg bimetallic nanoparticles for catalytic and heat transfer applications

Bimetallic nanoparticles (BNPs) have drawn significant attention due to their numerous applications. They demonstrate enhanced optical, electrical, thermal, and catalytic properties due to the synergistic effects of monometals present in them. In this work, CuAg and AuAg BNPs have been synthesized using a facile and economical chemical reduction method. Optical characterization was carried out using UV–visible spectroscopy, and effect of pH on optical absorbance was studied. For CuAg and AuAg BNPs, optimum pH was observed to be at 9.4 and 6.39, respectively. Morphological investigation confirms the average diameters of CuAg and AuAg BNPs were to be 65 nm and 30 nm, respectively. Photocatalytic property illustrates the reduction of 4-nitrophenol to 4-aminophenol with a 92% conversion percentage in the presence of CuAg BNPs in 4 min, and rate constant for the reaction was measured to be 8.98 × 10–3 s−1. But for the AuAg BNPs, the conversion percentage was 97% in 8 min and rate constant was found to be 7.95 × 10–3 s−1. Thermal conductivity and viscosity measurements of the nanofluids obtained with CuAg and AuAg BNPs have ascertained them to be efficient candidates for the heat transfer and catalytic applications.Graphic abstract

AgCu Bimetallic Electrocatalysts for the Reduction of Biomass-Derived Compounds.

The electrochemical transformation of biomass-derived compounds (e.g., aldehyde electroreduction to alcohols) is gaining increasing interest due to the sustainability of this process that can be exploited to produce value-added products from biowastes and renewable electricity. In this framework, the electrochemical conversion of 5-hydroxymethylfurfural (HMF) to 2,5-bis(hydroxymethyl)furan (BHMF) is studied. Nanostructured Ag deposited on Cu is an active and selective electrocatalyst for the formation of BHMF in basic media. However, this catalyst deserves further research to elucidate the role of the morphology and size of the coated particles in its performance as well as the actual catalyst surface composition and its stability. Herein, Ag is coated on Cu open-cell foams by electrodeposition and galvanic displacement to generate different catalyst morphologies, deepening on the particle growth mechanism, and the samples are compared with bare Ag and Cu foams. The chemical–physical and electrochemical properties of the as-prepared and spent catalysts are correlated to the electroactivity in the HMF conversion and its selectivity toward the formation of BHMF during electroreduction. AgCu bimetallic nanoparticles or dendrites are formed on electrodeposited and displaced catalysts, respectively, whose surface is Cu-enriched along with electrochemical tests. Both types of bimetallic AgCu particles evidence a superior electroactive surface area as well as an enhanced charge and mass transfer in comparison with the bare Ag and Cu foams. These features together with a synergistic role between Ag and Cu superficial active sites could be related to the twofold enhanced selectivity of the Ag/Cu catalysts for the selective conversion of HMF to BHMF, that is, >80% selectivity and ∼ 100% conversion, and BHMF productivity values (0.206 and 0.280 mmol cm–2 h–1) ca. 1.5–3 times higher than those previously reported.

Formation of SERS-substrate based on Ag-Cu bimetallic nanoparticles for detection of ultra-small amounts of substance

The aim of this work was to determine the sensitivity threshold and enhancement factor of a planar SERS substrate based on an array of composite Ag - Cu nanoparticles. The nanoparticles were deposited using the method of vacuum-thermal evaporation followed by annealing at 300 ° C. Methylene blue was chosen as the analyte. The possibility of detecting the micro- and nanomolar concentration of methylene blue using a SERS-substrate with an active Ag-Cu layer at a laser wavelength of 632.8 nm is shown. The use of such arrays of nanoparticles as an active layer makes it possible to achieve an analytical enhancement factor of the SERS substrate of the order of 6×105.

Metal incorporated Philippine Abaca fiber (Manila hemp) as a potential novel filter for water disinfection

The contamination of water sources by pathogenic bacteria poses a threat both in the environment and in human health. The incorporation of metal nanoparticles in polymer matrix which is abundantly available in a country can be improved to enhance its antimicrobial property. This study was focused on the development of a novel antibacterial water filter from synthesized silver-copper nanoparticles (Ag-CuNPs) incorporated into Philippine abaca fiber (Manila Hemp). Pre-treatment method and determination of adsorption capacity of abaca fiber towards metal ions, Ag+ and Cu2+ were done prior to synthesis of Ag, Cu and Ag-Cu nanocomposites. Alkali treatment of the fiber confirms OH, C-O and C=O of a cellulose, pectin and lignin in the FTIR analysis. These groups effectively altered the nature of the abaca fiber to hydrophobic, thus, increasing its adsorption capacity up to 80%. Morphological and structural properties of the formed nanoparticles were confirmed using scanning electron microscopy (SEM) revealing polymeric matrices of the fiber in the particle size of 80 nm – 100nm. UV-Vis spectra revealed a broadening of the absorption spectra of a bimetallic Ag-Cu nanoparticles at 410 nm. The antimicrobial assay results revealed promising synergism of the combined silver and copper nanoparticles against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacterial strains in synthetically prepared water. Also, a relatively proximate bactericidal efficiency was attained between the CuNPs and Ag-CuNPs abaca fiber composites. The developed Ag-CuNPs abaca fiber composite can act as novel antibacterial water filter for water disinfection.

Bimetallic Ag-Cu nanoparticles anchored on polypropylene (PP) nonwoven fabrics: Superb catalytic efficiency and stability in 4-nitrophenol reduction

Herein, a convenient and environment-friendly grafting and reduction strategy was used to anchor bimetallic Ag-Cu nanoparticles on polypropylene (PP) fabrics. The as-prepared samples were characterized by various techniques including FE-SEM, XRD, EDX, XPS and FT-IR. The as-prepared sample exhibits excellent activity on the catalytic reduction of highly concentrated 4-NP, and the synergisticeffect between Ag and Cu nanoparticles was proved. The entire catalytic reduction was generally considered to obey pseudo-order kinetics, affording high conversion even after 15 successive recycles. These results showed that the PP based composite with Ag-Cu nanoparticles effectively provided superb catalytic efficiency and stability in 4-nitrophenol reduction, and the PP based composites were suitable in practical applications for the treatment of diverse waste water.