High-purity Nanoparticles Research Articles

Enhancement of copper nanoparticle yield in magnetron sputter inert gas condensation by applying substrate bias voltage and its influence on thin film morphology

Large-scale synthesis of high-purity nanoparticles is an intense topic of scientific research, with magnetron sputter inert gas condensation recognized as a promising, environmentally friendly technique avoiding wet chemical processes. This study explores the deposition of size-selected nanoparticles under varied substrate bias voltages and reports on a consequent increase in deposition rates up to 32 %. These alterations in substrate bias voltage induce a progressive change in the morphology of the resulting nanoparticle thin films, attributable to the increased kinetic energy of the nanoparticles. Comprehensive characterization via quadrupole mass spectroscopy of the nanoparticle flux, scanning electron microscopy, X-ray photoelectron spectroscopy, and low-energy ion scattering spectroscopy of the deposited nanoparticles corroborates the enhanced nanoparticle yield associated with increased substrate bias voltage. These findings signify a methodological advancement, enhancing the efficiency of magnetron sputter inert gas condensation and moving the technology a step further towards feasible industrial production.

Exploring the utilitarian aspects of a noxious exotic weed, Lantana camara: From green synthesized nanoparticles to a new frontier in biomedical innovation

The quest for potent wound healing agents has prompted the exploration of nanotechnology, particularly the use of nanoparticles synthesized via green methods. There is a growing need to create appropriate wound dressing material with exceptional features, such as antibacterial activity, biocompatibility, free radical scavenging capacity, and more, to effectively treat chronic wounds. The leaf extract of Lantana camara (LC), an invasive exotic weed is utilized in this research to produce silver nanoparticles (LC-AgNPs) and zinc oxide nanoparticles (LC-ZnONPs) in an ecologically sustainable manner with a special emphasis on their wound healing applications. Different analytical techniques were employed to characterize the biogenic nanoparticles that were synthesized, such as UV-VIS, XRD, SEM EDAX and TEM. The UV–visible absorbance peaks at 450 nm and 370 nm, respectively, confirmed the nanoscale presence of silver and zinc oxide particles. X-ray diffraction analysis demonstrated that the particles were exceptionally crystalline. Analysis by energy-dispersive X-ray confirmed the presence of ZnO and silver nanoparticles of high purity. The antibacterial and antifungal activities of LC-Ag NPs and LC-ZnONPs against Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 25923), Aspergillus niger (ATCC 16404), and Candida albicans (ATCC 10231) were evaluated using the disc diffusion method. The remarkable efficacy exhibited by the synthesized particles against bacteria and fungi suggests that they may find utility in antimicrobial and antifungal applications. ZnO nanoparticles also exhibited excellent antioxidant activity. The LC50 value of 42.58 μg/mL for LC-AgNPs is significantly lower than that of 79.66 μg/mL for LC-ZnONPs, as determined by cytotoxicity studies. This discrepancy suggests that LC-ZnONPs may be a more suitable material for applications involving wound healing in a cost-effective manner. This research highlights the revolutionary effects of nanotechnology in the field of biomedicine and illustrates an environmentally benign, economical, and sustainable use of L. camara.

Synthesis, characterization, and synergistic effects of CuS/MnO2 nanocomposite electrodes for high-performance supercapacitors

Metal oxides, metal sulfides, and their derivatives exhibit impressive electrochemical capabilities, offering potential for the creation of novel electrodes with superior performance in supercapacitors. In this study, we introduce a novel binary composite consisting of copper sulfide and manganese oxide (CuS/MnO2). This composite is designed with specific CuS and MnO2 ratios (80 % and 20 %, respectively) to explore their electrochemical behavior and optimize the performance of these nanostructures. According to morphological and structural analysis, it was observed that the synthesis process yielded high-purity nanoparticles and nanorods of CuS and MnO2. Notably, no byproducts were detected, indicating a successful synthesis process. Through a rapid pseudocapacitive charge storage mechanism, the electrochemical investigations reveal that all electrodes in a three-electrode setup tested in 3 M KOH electrolyte solution and the novel CuS/MnO2 electrode exhibit typical capacitive behavior in the potential of 0.0–0.5 V, with good reversibility and charge storage properties (specific capacitance: 451 F g−1, low resistance: 1.21 Ω, cyclic stability: 98.33 % at 4 A g−1 continuously 2000 cycles). Surprisingly, the CuS/MnO2 nanocomposite (NC) exposed high power density is about 1997 W kg−1 and a maximum energy density of 28.19 W h kg−1exceptionally is achieved. The significance of additional transition metal oxide-based electrodes in achieving noticeably better performance is demonstrated by these results.

Studying the Structure Properties of Copper Nanoparticles Prepared by Chemical Reduction Method

The chemical reduction method (CRM) can produce high purity nanoparticles, it is a down-top chemical method based on the principle of salt reduction, this method is used in this work to synthesis copper nanoparticals (CuPNs) by use different concentrations of copper nitrate. The properties of the prepared nanoparticles were studied by fourier transform infrared (FTIR) and ultraviolet-visible (UV-Vis) spectroscopy were used to measure the absorbance spectra of the produced particles. According to the scanning electron microscope (SEM), the particles’ diameters range from (61.64 to 49.25) nm. According to X-ray diffraction, the particles exhibit a face monoclinic crystal structure (FCC). According to the transmission electron microscope findings, the particles are asymmetrically spherical in shape.

Photomechanical Laser Fragmentation of IrO2 Microparticles for the Synthesis of Active and Redox-Sensitive Colloidal Nanoclusters.

Pulsed laser fragmentation of microparticles (MPs) in liquid is a synthesis method for producing high-purity nanoparticles (NPs) from virtually any material. Compared with laser ablation in liquids (LAL), the use of MPs enables a fully continuous, single-step synthesis of colloidal NPs. Although having been employed in several studies, neither the fragmentation mechanism nor the efficiency or scalability have been described. Starting from time-resolved investigations of the single-pulse fragmentation of single IrO2 MPs in water, the contribution of stress-mediated processes to the fragmentation mechanism is highlighted. Single-pulse, multiparticle fragmentation is then performed in a continuously operated liquid jet. Here, 2nm-sized nanoclusters (NCs) accompanied by larger fragments with sizes ranging between several ten nm and several µm are generated. For the nanosized product, an unprecedented efficiency of up to 18µgJ-1 is reached, which exceeds comparable values reported for high-power LAL by one order of magnitude. The generated NCs exhibit high catalytic activity and stability in oxygen evolution reactions while simultaneously expressing a redox-sensitive fluorescence, thus rendering them promising candidates in electrocatalytic sensing. The provided insights will pave the way for laser fragmentation of MPs to become a versatile, scalable yet simple technique for nanomaterial design and development.

Complex Oxide Nanoparticle Synthesis: Where to Begin to Do It Right?

Synthesis of advanced ceramics requires a high degree of control over the particle size and stoichiometry of the material. When choosing a synthesis method for complex oxides it is important to begin with the correct precursors and solvents to achieve high purity nanoparticles. Here, we detail the selection process for precursors and solvents for liquid-phase precipitation synthesis. Data for metal nitrate, chloride, acetate, and oxalate precursors has been compiled to assist future synthesis. The role of hydration within the precursors is discussed as it affects the final stoichiometry of the material. Melting temperatures are also compiled for these compounds to assist in material selection. The solubility of the precursors in different solvents is examined to determine the correct solvent during synthesis. As an example, using the methodology presented here, two different materials are synthesized based on commonly available precursors. A catalyst based on a quaternary perovskite and an advanced ionic conductor based on a high entropy fluorite oxide are synthesized using precipitation methods and their characterization is detailed.

Optical and Structural Properties of Cobalt Nanoparticles Synthesized by Laser Ablation

Pulsed laser ablation in liquid (PLAL) technique can produce high purity nanoparticles, it is a top-down physical method based on the principle of dividing metal ion bulk precursors into metal atoms, this method was used in this work to synthesis cobalt nanoparticals (CoPNs) with the use of Nd: YAG laser with two wavelengths (355 nm) and (532 nm) at energies (500 mJ) and (600 mJ) respectively, with number of pulses (1000,1100, 1200, 1300, and 1400) for each wavelength. The properties of the prepared nanoparticles were studied by UV-Vis, XRD, SEM with EDX, AFM, and FTIR analysis and then its antibacterial activity was studied by applying it on two types of bacteria with gram-positive (Staphylococcus aureus, Streptococcus mutans) and two gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa) isolated from the oral cavity. The findings showed that CoNPs prepared using the PLAL approach have antibacterial activity and could be employed to kill hazardous and pathogenic bacteria.

Biogenic nanoparticles and generation of abiotic stress-resilient plants: A new approach for sustainable agriculture

Agricultural crop production is getting a significant setback due to global warming and climate change in the modern era. These two factors have significantly induced the severity of abiotic stresses such as drought, salinity, extreme temperature and heavy metal toxicity. Upon being exposed to harsh environmental conditions, cytotoxic metabolites such as reactive oxygen species are generated which in turn disturb the homeostatic balance of cells along with inciting membrane damage. In order to overcome the negative effects of abiotic stresses, plant and agrarian scientific reports have shown significant progresses in promoting the efficient and eco-friendly approaches for the synthesis of plant- and microorganism-based synthesis of nanoparticles. Owing to their nanoscale size, nanoparticles possess a large surface/volume ratio that significantly alters their property and characteristic as compared to that of their normal counterparts. Nanoparticles can be physically, chemically and biologically synthesised. While physical and chemical methods have been successfully applied for the generation of nanoparticles of high purity and desired size, these processes are costly and require toxic chemicals. Thus, in the modern era, several investigators have focused their interest on biological methods of nanoparticle synthesis, since such methods are fast, cost effective and eco-friendly. In this review, we attempt to deliver information about plant- and microorganism-mediated synthesis of nanoparticles, based on recent scientific works. We also demonstrate the significance of these nanoparticles in the mitigation of negative impact of abiotic stresses on crop plants which might come handy in near future to the agricultural community.

Synthesis of Titanium Oxide Nanoparticles Using Pulsed Laser Ablation Method in Deionized Water

The synthesis of titanium oxide nanoparticles (TiO2NPs) has been successfully carried out using pulsed laser ablation in deionized water to produce titanium oxide nanoparticles. This synthesis is included in the top-down method which aims to produce high-purity nanoparticles synthesis. Experimentally, an Nd:YAG laser beam (with 1064 nm, 85 mJ and 10 Hz) was focused on the surface of a high-purity (99.9%) titanium plate placed in deionized water. The high energy pulsed laser Nd:YAG laser makes the titanium plate ablate for 30 minutes. This is because the melting of the titanium plate surface causes the formation of small titanium oxide particles. When these particles hit deionized water this synthesis titanium oxide will form a colloid. Furthermore, colloidal titanium oxide nanoparticles have been successfully produced with a bluish-white color. The absorbance of TiO2NPs was shown at 239.75 nm as the appearance of colloidal TiO2NPs and the average diameter at 73.47 nm. Therefore the synthesis of TiO2NPs by pulsed laser ablation method can produce nanoparticles.

Formation of gold/silver composite nanoparticles by pulsed laser ablation of gold–silver layered films in liquid

Nanoparticles of high purity can be produced from a variety of materials by pulsed laser ablation of solids in liquid. Composite nanoparticles are of great importance in various applications such as catalysis or biomedicine and the process of their formation is still a subject of intense research. In this work, gold/silver composite nanoparticles were synthesized in aqueous media by ns pulsed laser ablation of gold–silver multilayer targets with different absolute layer thicknesses and layer thickness ratios. The generated nanoparticles showed a log-normal distribution of sizes, with average diameter in the 20–40 nm range and standard deviation of 9–30 nm. By comparing the UV–VIS absorbance spectra of the nanoparticle colloids with two theoretical calculations (based on the Mie and the BEM model), it was found that there is a direct correlation between the average Au and Ag content of the nanoparticles and the composition of the films on the substrate. Assuming thermal ablation, our model calculations showed that there is a maximum thickness of the top layer up to which both layers can be ablated simultaneously and alloy nanoparticles can be produced.

Characterization of the coating structure and stability of core–shell Al nanoparticles generated by using pulsed laser ablation in acetone

Al nanoparticles are of significant interest due to their enhanced energetic properties and applicability in optics, biology, and the energy industry. We demonstrate the synthesis of core–shell Al nanoparticles via pulsed-laser-ablation-in-liquid, which reduces oxide formation and increases their resistance to reactive environments. When a bulk Al target was ablated in an organic solvent (acetone), high purity nanoparticles with a high Al content in the core part were generated. The size of the nanoparticles (6–7 nm) was not significantly changed according to the experimental conditions. However, low laser energy intensity is preferable due to less aggregation of nanoparticles and low impurity content. Amorphous and graphite carbon species were found in the coating of the core–shell Al nanoparticles. In addition, we show evidence of enolates or carboxylates in the coating material, as evidenced via energy dispersive spectroscopy and Fourier-transform infrared spectroscopy. Aging experiments in deionized water revealed that the passivated Al nanoparticles could maintain high purity in the core part and high stability in reactive environments such as water.

Enzyme protects bacteria from toxic gold

Certain bacteria protect themselves from a toxic form of gold by transforming it into high-purity nanoparticles. Researchers have now identified a gold-reducing enzyme, called GolR, that is a key part of this process. They hope the enzyme—the first gold reductase known to science, they say—could be used to harvest gold from electronic waste ( JACS Au 2022, DOI: 10.1021/jacsau.2c00170 ). The team found GolR in a bacterium called Erwinia sp. IMH, which thrives in gold ore. The bacterium reduces toxic gold(III) compounds, which can generate reactive oxygen species that harm the bacteria, into less toxic gold nanoparticles. “Although this metal is precious to humans, bacteria hate it,” says team member Chuanyong Jing of the Research Center for Eco-Environmental Sciences at the Chinese Academy of Sciences. To find GolR, the researchers studied which of Erwinia ’s genes were spurred into action by gold(III). When they deleted the most activated gene, the

Influence of Number of Pulses on Characterization of Nanoparticles of Copper and its Oxides Synthesized by Nd: YAG Laser Ablation Technique and its Antibacterial Activity

Pulsed laser ablation in liquid (PLAL) technique can produce high purity nanoparticles, it is a top-down physical method based on the principle of dividing metal ion bulk precursors into metal atoms, this method is used in this work to synthesis copper nanoparticals (CuPNs) by use Nd: YAG laser with two wavelengths (355 nm) and (532 nm) at energies (500 mJ) and (600 mJ) respectively, with number of pulses (700, 800, 900, 1000, and 1100 P) for each wavelength. The properties of the prepared nanoparticles were studied by UV-Vis, XRD, SEM with EDX, AFM, and FTIR analysis and then study its antibacterial activity by applying it on two types of bacteria with Gram-positive (Staphylococcus aureus, Streptococcus mutans) and two Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa) isolated from the oral cavity. The findings show that CuNPs made using the PLAL approach have antibacterial activity and could be employed to kill hazardous and pathogenic bacteria.

Silver Nanoparticles Synthesized By Nd: YAG Laser Ablation Technique: Characterization and Antibacterial Activity

The pulsed laser ablation in liquid (PLAL) technique can produce high purity nanoparticles, it is a top-down physical method based on the principle of dividing metal ion bulk precursors into metal atoms, this method was used in this work to synthesize silver nanoparticles (AgPNs) by using Nd: YAG laser with two wavelengths (355 nm) and (532 nm) at energies (500 mJ) and (600 mJ) respectively, with the number of pulses (500, 600, 700, 800, and 900 pulses) for each wavelength. The properties of the prepared nanoparticles were investigated by UV-Vis, XRD, SEM with EDX, AFM, and FTIR analysis and then tested for antibacterial activity against two Gram-positive bacteria (Staphylococcus aureus, Streptococcus mutans) and two Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa) isolated from the oral cavity. The findings demonstrated that AgNPs generated via the PLAL method have antibacterial activity and could be employed to kill dangerous and pathogenic bacteria.

Control of the size of nanoparticles by spark discharge with an atomizer and a bubbler

We propose a simple method to control the size of nanoparticle generated by spark discharge. Nanoparticle characteristics are of importance for numerous applications. Property control can lead to desired applications. The spark discharge method can generate nanoparticles of high purity with ease. A pin-to-plate type spark discharge-nanoparticle generator (SDG) solely created approximately 1.3×108 metal particles/cm3 of geometric mean diameter (GMD) of 20.4 nm. Instead of pure gas, ethanol vapor and droplets from an atomizer were introduced into the SDG. The GMD was increased to 40.0 nm similar to the size of particles generated from the atomizer. The differences in discharge voltage and frequency were too small to change nanoparticle characteristics. To investigate this phenomenon, a bubbler replaced the atomizer and various solvents were used such as ethanol, methanol, and water. The GMD was reduced to 14.6 nm when the methanol bubbler was used. Organic solvent decreased GMD with decreased number concentration, while water did not contribute to the change in particle size. This suggests that vapor from the bubbler suppresses homogeneous nucleation while droplets from the atomizer induce heterogeneous nucleation. This research can be applied to nanoparticle control techniques for production processes.Copyright © 2022 American Association for Aerosol Research

Preparation of dense B4C ceramics by spark plasma sintering of high-purity nanoparticles

Boron carbide (B4C) is an important structural ceramic material, however, the use of this material is limited by its poor sinterability and low fracture toughness. Nano-sized powders have small particle size, high chemical activity and great sintering ability, which can promote the fabrication of the dense B4C ceramics. Herein, by spark plasma sintering (SPS) homemade high-purity nanopowders, single phase B4C ceramics with density close to the theoretical value were prepared. Results showed that the best SPS condition was holding at temperature of 1850 °C for 4 min. Under this condition the sample exhibited enhanced mechanical properties including Vickers hardness of 33.9 GPa, fracture toughness of 3.81 MPa m1/2 and flexure strength of 554.7 MPa. Transmission electron microscopy (TEM) analysis shows that non-coherent twins exist at the grain boundary instead of amorphous phase or second phase, which further confirms the high purity and high densification of the obtained B4C ceramics.

Factors affecting the formation of plasma on Fe, Cu and W electrodes using an electrochemical reaction in an aqueous environment with high-voltage DC

Plasma creation technology in an aqueous environment is being evaluated for research and practical applications, particularly in the field of materials and nano processing, as well as environmental pollution treatment. Important factors that influence the appearance of plasma when performing electrolysis by high-voltage DC (direct current) in aqueous environments are voltage, distance between electrodes, pH, conductivity and ambient temperature, as well as the nature of the electrode, which has been suggested by concurrent works to be the controlling factor of the other ones. Specifically, it is indicated that the plasma typically appears at a high voltage of about 15 kV and a distance between electrodes of 200 mm, with the earliest appearance occurring with the tungsten (W) electrode. Additionally, pH, conductivity and temperature variations for effective plasma creation have been found in all investigated electrodes. Finally, it has been found that the water-soluble plasma on the W electrode produces more gas than those in iron (Fe) and copper (Cu) electrodes. After the reactions, the lowest dissolution belonging to W electrode could be attributed to the inertness of W in comparison with Fe and Cu, resulting in a minimal value of the zeta potential. In addition, the size of Cu and Fe nanoparticles achieved in the investigated solution was approximately 200 nm, whereas W nanoparticles were two separate sizes of 100 and 500 nm. Therefore, this work could offer the needed agency for technological applications in industrial wastewater treatment and high-purity nanoparticle fabrication.

Characterization of nanosized hydroxyapatite prepared by an aqueous precipitation method using eggshells and mulberry leaf extract

Hydroxyapatite (HA) has been vigorously studied for orthopedic and dental applications due to its excellent bioactivity, osteoconductivity, and osteoinductivity. This study aims to present a simple room-temperature aqueous precipitation method for obtaining carbonated HA nanoparticles of high purity from biowaste chicken eggshells. Biowaste chicken eggshells were used for preparing HA through aqueous precipitation method. Moreover, mulberry leaf extract was used as a template to regulate the morphology, size, and crystallinity of HA. All produced nanocrystalline HA powders exhibited rod-like particle agglomerates of a size below 100 nm. The HA particles synthesized with the mulberry leaf extract showed higher crystallinity and slightly decreased crystallite sizes compared to the samples prepared without adding the extract. Carbonate peaks observed for the specimens closely matched those of A- and B-type carbonates, which can contribute to the low crystallinity. Notably, the HA synthesized from the eggshell powders contains several important trace elements such as Mg and Sr, which are beneficial to the overall biological performance as biomaterials. The morphology, size, structure, and composition of the obtained HA products are similar to those of natural bones, and consequently, the products show potential as a material for biomedical applications.

Phosphorus-doped CoS2 nanoparticles with greatly enhanced electrocatalytic performance as Pt-free catalyst for hydrogen evolution reaction in acidic electrolyte

In the present study, we have proposed the phosphorus (P)-doped CoS2 electrocatalyst through a simple hydrothermal route and utilized as an economical and earth-abundant electrocatalyst for hydrogen evolution reaction (HER). A sequence of P-doped CoS2 electrocatalysts were obatined by using different NaH2PO4 contents. The as-synthesized samples were characterized by XRD, SEM, HR-TEM, element mapping, and XPS analyses. It is found that these P-doped CoS2 materials composed of high purity nanoparticles and stacked in a block structure. The electrochemical performance has been investigated in 0.5-M H2SO4 electrolyte. The results indicate that the doping of phosphorus can significantly increase the electrocatalytic hydrogen evolution activity of CoS2. Among the different samples, the P-doped CoS2 attained with 5 mmol of NaH2PO4 contents offers the highest HER performance with a minimum overpotential of 109 mV at 10 mA cm-2, the smallest Tafel slope of 48 mV dec-1, and an excellent long-term durability over 1,000 cycles. The analysis results illustrate that the doped phosphorus may change the internal properties of CoS2, which promotes the ability of charge transfer and electrochemical active sites, resulting in the significantly increased HER activity compared with bare CoS2. Therefore, this work demonstrates that a proper doping of phosphorus is a suitable approach to improve the catalytic ability of metal sulfides for HER application.

Co-sputtering of gold and copper onto liquids: a route towards the production of porous gold nanoparticles

Effective methods for the synthesis of high-purity nanoparticles (NPs) have been extensively studied for a few decades. Among others, cold plasma-based sputtering metals onto a liquid substrate appears to be a very promising technique for the synthesis of high-purity NPs. The process enables the production of very small NPs without using any toxic reagents and complex chemical synthesis routes, and enables the synthesis of alloy NPs which can be the first step towards the formation of porous NPs. In this paper, the synthesis of gold-copper alloy NPs has been performed by co-sputtering gold and copper targets over pentaerythritol ethoxylate. The resulting solutions contain a mixture of gold, copper oxide, and alloy NPs having a radius of few angstroms. The annealing of these NPs, inside the solution, has been performed in order to increase their size and further induce the dealloying of the Au-Cu NPs. The resulting NPs exhibit either a nanoporous structure or are self-organized in an agglomerate of small NPs.