Formation Of Oxide Nanoparticles Research Articles

Cerium oxide nanoparticles formation and aggregation dynamics

The conventional synthesis of cerium oxide nanoparticles (CeNPs) relies on the use of trivalent cerium and an oxidizer to ensure a thorough hydrolysis. This study explores CeNPs formation via the hydrolysis of tetravalent cerium, specifically through the spontaneous reaction of ceric ammonium nitrate (Ce(NH4)2(NO3)6) under varied aging conditions, including adjustments in pH, concentration, and heating strategy. This research adopts a thermo-hydrolysis method to synthesize CeNPs with small primary particles (2–3 nm) to loose dendritic clusters (5–8 nm). Additionally, when the starting pH of the solution decreases below 0.8, it favors the formation of clusters with larger diameters (15–20 nm). Analyses using dynamic light scattering (DLS), high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS) indicate that CeNPs particle size in acidic environments is predominantly determined by the extent of primary particle aggregation, influenced by nitrate adsorption. Overall, our comprehensive analysis of the CeNPs evolution provides fundamental insights for the development of a size/structure controllable synthetic strategy for nanoparticle manufacturing.

Cubic Mesocrystal Magnetic Iron Oxide Nanoparticle Formation by Oriented Aggregation of Cubes in Organic Media: A Rational Design to Enhance the Magnetic Hyperthermia Efficiency

Cubic Mesocrystal Magnetic Iron Oxide Nanoparticle Formation by Oriented Aggregation of Cubes in Organic Media: A Rational Design to Enhance the Magnetic Hyperthermia Efficiency

Reactive introduction of oxide nanoparticles in additively manufactured 718 Ni alloys with improved high temperature performance

Alloy 718 has been intensively investigated for additive manufacturing. While previous studies on additively manufactured alloy 718 typically have metallic phases only, in this work, we show that oxide nanoparticles can be introduced into alloy 718 via a reactive sintering mechanism. The introduction of micron scale Cr 2 O 3 powder in alloy 718 powder led to the formation of a homogeneous distribution of Al and Ti rich oxide nanoparticles. This surprising finding arises from the chemical reaction between oxide powders and metal matrix containing Al and Ti. In comparison to the control alloy 718 without oxides, the presence of oxide nanoparticles dramatically alters the microstructure, leading to a relatively more equiaxed grain structure, while also reducing the residual stress. While the mechanical testing between the two material groups demonstrates comparable mechanical strength and tensile ductility at room temperature, the high-temperature (900 °C) mechanical properties of the oxide containing 718 samples were significantly improved over the control 718 samples. The apparent possibilities of using this reactive process to introduce oxide nanoparticles into metallic materials may have a general implication for the fabrication of oxide dispersion in various metal matrices via reactive additive manufacturing. • Production of nano oxide dispersion strengthened alloy 718 • Reactive formation of oxide nano particles creates a (Al,Ti) 2 O 3 chemistry • Reduction of residual stress via the oxide particles accommodating residual stress • Increased high-temperature mechanical properties up to 900 °C

A versatile chemical vapor synthesis reactor for in situ x-ray scattering and spectroscopy.

We describe a versatile reactor system for chemical vapor synthesis of nanoparticles, which enables in situ investigations of high temperature gas phase particle formation and transformation processes by x-ray scattering and x-ray absorption spectroscopy. The system employs an inductively heated hot wall reactor as the energy source to start nanoparticle formation from a mixture of precursor vapor and oxygen. By use of a modular set of susceptor segments, it is especially possible to change solely the residence time of the gas mixture while keeping all other process parameters (temperature, gas flow, pressure) constant. Corresponding time-temperature profiles are supported by computational fluid dynamics simulations. The operation of the system is demonstrated for two example studies: tin oxide nanoparticle formation studied by small angle x-ray scattering and iron oxide nanoparticle formation by x-ray absorption spectroscopy.

Attempts to obtain BaTiO3/Fe2O3 core-shell type structures: The role of iron oxide nanoparticle formation and agglomeration

• Magnetometric studies of the BaTiO 3 /Fe 2 O 3 samples prepared using five different chemical routes were done. • Decoration of BaTiO 3 grains with hematite nanoparticles was observed instead.of a well defined core-shell structure. • Tendency of the iron-oxide nanoparticles to form agglomerates reduces the possibility of a continuous shell formation around the core. • Magnetic properties of these composites are dominated by the properties of fine iron-oxide nanopowder. The manuscript shows the studies of structural and magnetic properties of BaTiO 3 /Fe 2 O 3 samples prepared using five different chemical routes. We show that the undertaken processes leaded to the decoration of BaTiO 3 grains with hematite nanoparticles, but not to a creation of a well-defined core-shell structure. These studies revealed that a strong tendency of the iron-oxide nanoparticles to form agglomerates, significantly reduces the possibility of a continuous shell formation around the core, and at the same time it promotes inter-particle interactions between magnetic nanoparticles. A detailed analysis of the results obtained in the structural and magnetic studies, allowed to state that magnetic properties of these composites are dominated by the properties of fine iron-oxide nanopowder. The collected isothermal magnetization curves clearly indicate the canted antiferromagnetic properties characteristic for hematite, while the ac magnetization results exhibit the collective freezing process to the cluster glass like state (characteristic for interacting system of magnetic nanoparticles). This work provides detailed studies of systems prepared under different conditions and methods, which can serve as an important step towards obtaining well defined BaTiO 3 /Fe 2 O 3 core-shell structures.

Green synthesis of silver oxide nanoparticles using Panicum miliaceum grains extract for biological applications

In this report, the silver oxide nanoparticles were green synthesized using Panicum miliaceum grains extract and were proposed for the first time. GC–MS analysis explicated 2-Acetylbenzoic acid was the active phytocompound with 97.07% of presence in aqueous grains extract. The synthesized silver oxide nanoparticles were analyzed by several analytical techniques such as UV–visible, XRD, FT-IR, HR-TEM, TG, XPS, EDX and mapping analyses. The results of various analytical techniques confirmed the silver oxide nanoparticles formation. The formed nanoparticles were in 10–25 nm size. The effectual bioactive properties of nanoparticles were revealed through antioxidant, anti-diabetic, anti-inflammatory, larvicidal and insecticidal activities. The high mortality of larvae and insect was observed at 48 h in 100 ppm and 72 h in 100 μg/Kg concentration, respectively. The antibacterial activity explained the bactericidal property of nanoparticles on S. aureus and S. typhi at 150 μg/mL concentration. The effective drug activity of nanoparticles was observed from 98.10 % of toxicity against A549 lung cancer cells at 100 μg/mL concentration. The growth of Vigna unguiculata was efficiently increased by lower concentration (60 ppm) of nanoparticles. According to results, the green synthesized nanoparticles can be applied in pharmaceutical and agricultural sectors as biocompatible, non-toxic and cost-effective material.

New Approach to Non-Invasive Tumor Model Monitoring via Self-Assemble Iron Containing Protein Nanocompartments.

According to the World Health Organization, breast cancer is the most common oncological disease worldwide. There are multiple animal models for different types of breast carcinoma, allowing the research of tumor growth, metastasis, and angiogenesis. When studying these processes, it is crucial to visualize cancer cells for a prolonged time via a non-invasive method, for example, magnetic resonance imaging (MRI). In this study, we establish a new genetically encoded material based on Quasibacillus thermotolerans (Q.thermotolerans, Qt) encapsulin, stably expressed in mouse 4T1 breast carcinoma cells. The label consists of a protein shell containing an enzyme called ferroxidase. When adding Fe2+, a ferroxidase oxidizes Fe2+ to Fe3+, followed by iron oxide nanoparticles formation. Additionally, genes encoding mZip14 metal transporter, enhancing the iron transport, were inserted into the cells via lentiviral transduction. The expression of transgenic sequences does not affect cell viability, and the presence of magnetic nanoparticles formed inside encapsulins results in an increase in T2 relaxivity.

Oxidation Behaviour of Microstructurally Highly Metastable Ag-La Alloy.

A new silver-based alloy with 2 wt.% of lanthanum (La) was studied as a potential candidate for electric contact material. The alloy was prepared by rapid solidification, performed by the melt spinning technique. Microstructural examination of the rapidly solidified ribbons revealed very fine grains of αAg and intermetallic Ag5La particles, which appear in the volume of the grains, as well as on the grain boundaries. Rapid solidification enabled high microstructural refinement and provided a suitable starting microstructure for the subsequent internal oxidation, resulting in fine submicron-sized La2O3 oxide nanoparticle formation throughout the volume of the silver matrix (αAg). The resulting nanostructured Ag-La2O3 microstructure was characterised by high-resolution FESEM and STEM, both equipped with EDX. High-temperature internal oxidation of the rapidly solidified ribbons essentially changed the microstructure. Mostly homogeneously dispersed nano-sized La2O3 were formed within the grains, as well as on the grain boundaries. Three mechanisms of internal oxidation were identified: (i) the oxidation of La from the solid solution; (ii) partial dissolution of finer Ag5La particles before the internal oxidation front and oxidation of La from the solid solution; and (iii) direct oxidation of coarser Ag5La intermetallic particles.

Biomimmetic ZrO 2 @ PdO nanocomposites: fabrication, characterization, and water splitting potential exploration

Semiconducting metal oxide nanostructures have the potential to play a significant role for introducing a new podium for alternative energy technologies, such as energy storage and conversion via photovoltaic array, solar fuels, and water electrolysis. To be able to build high-performance fuel cells and electrocatalysts to meet energy demand, it is critical to develop abundant and cheap electrocatalysts to address fossil fuel reduction and the energy crisis. Current study reports the first investigation on nanocomposite of Zirconia and palladium oxide (ZrO2@PdO) as an electrode material synthesized by a biomimetic approach. Biosynthesized ZrO2@PdO nanocomposites had direct band gaps of 4.5 and 3.5 eV, as measured by ultraviolet spectrophotometry capped by organic functional groups as revealed by Fourier-transform infrared spectroscopy. Formation of oxide nanoparticles was confirmed through UV-Vis spectroscopy with peaks exhibition between 300 and 400 nm. Polycrystalline phase patterns were determined by x-ray diffraction with average crystallite sizes of 12 nm. Scanning electron micrographs of nanocomposites revealed granular and uniform grain shapes, with strong signals for Zr, Pd, and O exposed by energy dispersive x-ray spectroscopy. X-ray photoelectron spectroscopy successfully revealed the capping of phytocompounds (C1s) as well as confirmed the composition of material with strong signals of Pd, Zr, and O1s. Electrochemical investigation included linear sweep voltammetry and electrochemical impedance spectroscopic (EIS) studies. The electrode performed well, with low overpotential value as well as Tafel slope value (64 mV/dec), signifying its effectiveness as oxidation catalyst. The Nyquist plot from EIS with an arc radius demonstrated the occurrence of resistance mechanism arising from interfacial region of electrode surface with charge transfer resistance (Rct) of only 3.23 Ω. ZrO2@PdO did not perform well for hydrogen evolution reaction under the same operating conditions, however, can be improved by optimizing the parameters. Active to electrochemical application manifested ZrO2@PdO a potential candidate for photovoltaic devices in term of economic viability and sustainability in comparison to environmentally harmful pathways.

Understanding the Nucleation and Growth of Iron Oxide Nanoparticle Formation by a “Heating-Up” Process: An NMR Relaxation Study

Understanding the Nucleation and Growth of Iron Oxide Nanoparticle Formation by a “Heating-Up” Process: An NMR Relaxation Study

Structural Characterization, Antimicrobial and Antioxidant Assay of Biogenically Synthesized Maghemite (γ-Fe2O3) Nanoparticles

Aims: The present study focused on the optical and morphological characterization, antioxidant and antimicrobial activities of the biogenically synthesized iron oxide nanoparticles. 
 Methods: The preliminary phytochemical screening was done for the leaf extract of Annona reticulate L. The leaf extract and Ferrous Sulphate heptahydrate were used to synthesize the iron oxide nanoparticles under room temperature. The determination of antioxidant activity was done using DPPH free radical scavenging assay and the determination of antimicrobial activity using disc diffusion method.
 Results: The UV-visible spectra showed the sharp absorption peak at 278 nm. The Fourier-transform infrared spectroscopy studies revealed the role of phytochemical constituents in the leaf extract for the iron oxide nanoparticles formation. X-ray diffraction pattern showed the presence of γ phase of Fe2O3 nanoparticles. Scanning electron microscope analysis showed the moderately spherical morphology of γ-Fe2O3 nanoparticles and Energy-dispersive X-ray peaks showed the presence of iron and oxygen in the synthesized nanoparticles. Particle size analysis showed that the synthesized γ-Fe2O3possessed an average size of 115.9 nm.
 Conclusion: The synthesized γ-Fe2O3 nanoparticles have potential antioxidant and antimicrobial activity.

Overcoming the Inhibition Effects of Citrate: Precipitation of Ferromagnetic Magnetite Nanoparticles with Tunable Morphology, Magnetic Properties, and Surface Charge via Ferrous Citrate Oxidation (Part. Part. Syst. Charact. 8/2021)

In article 2100098, Mandel and co-workers demonstrate how to solve the long known challenge to overcome the inhibition effects of citrate that are believed to hinder iron oxide nanoparticle formation from iron salt precursors when being present during the nanoparticle synthesis. This opens up routes to in-situ modification of nano iron oxides, thus making post-synthesis citrate modification obsolete.

Iron Oxide Nanoparticles – Characterization and Antimicrobial Studies

Nanotechnology is one of the most promising technologies that give us better outcomes from biological and industrial issues. This work ismainly based on the green synthesis of iron oxide nanoparticles, assisted by the flower extract. The nanoparticles were synthesized and characterized using UV Visible spectroscopy with characteristic absorbance peaks at 300 nm and 310 nm. Prominent Fourier-Transform Infrared Spectroscopy (FTIR) peaks were obtained corresponding to phenols, amide group, aromatic ring, hydroxyl group, and carbonate ions involved in the stabilization of iron oxide nanoparticles formation. Dynamic light scattering analysis of nanoparticles showed the average sizes as 80.7 nm. Scanning electron microscope images revealed that the size of iron nanoparticles in the range of 160-300 nm. The green synthesized iron nanoparticles have promising potential to inhibit the growth of bacteria. Iron oxide nanoparticles inhibit E. coli, B. subtilis, P. aeruginosa was also enumerated as antimicrobial study. The phytochemicals alkaloid, flavonoid, glycoside, terpenoid, and saponin present in theSenna auriculata may be attributed to reducing iron oxidenanoparticles.

Structural evolution of iron forming iron oxide in a deep eutectic-solvothermal reaction

Deep eutectic solvents (DES) and their hydrated mixtures are used for solvothermal routes towards greener functional nanomaterials. Here we present the first static structural and in situ studies of the formation of iron oxide (hematite) nanoparticles in a DES of choline chloride : urea where xurea = 0.67 (aka. reline) as an exemplar solvothermal reaction, and observe the effects of water on the reaction. The initial speciation of Fe3+ in DES solutions was measured using extended X-ray absorption fine structure (EXAFS), while the atomistic structure of the mixture was resolved from neutron and X-ray diffraction and empirical potential structure refinement (EPSR) modelling. The reaction was monitored using in situ small-angle neutron scattering (SANS), to determine mesoscale changes, and EXAFS, to determine local rearrangements of order around iron ions. It is shown that iron salts form an octahedral [Fe(L)3(Cl)3] complex where (L) represents various O-containing ligands. Solubilised Fe3+ induced subtle structural rearrangements in the DES due to abstraction of chloride into complexes and distortion of H-bonding around complexes. EXAFS suggests the complex forms [-O-Fe-O-] oligomers by reaction with the products of thermal hydrolysis of urea, and is thus pseudo-zero-order in iron. In the hydrated DES, the reaction, nucleation and growth proceeds rapidly, whereas in the pure DES, the reaction initially proceeds quickly, but suddenly slows after 5000 s. In situ SANS and static small-angle X-ray scattering (SAXS) experiments reveal that nanoparticles spontaneously nucleate after 5000 s of reaction time in the pure DES before slow growth. Contrast effects observed in SANS measurements suggest that hydrated DES preferentially form 1D particle morphologies because of choline selectively capping surface crystal facets to direct growth along certain axes, whereas capping is restricted by the solvent structure in the pure DES.

Synthesis of ZnO Nanoparticles Doped with Cobalt Using Bimetallic ZIFs as Sacrificial Agents.

We report here a simple two-stage synthesis of zinc–cobalt oxide nanoparticles. We used Zn/Co-zeolite imidazolate framework (ZIF)-8 materials as precursors for annealing and optional impregnation with a silicon source for the formation of a protective layer on the surface of oxide nanoparticles. Using bimetallic ZIFs allowed us to trace the phase transition of the obtained oxide nanoparticles from wurtzite ZnO to spinel Co3O4 structures. Using (X-ray diffraction) XRD and (X-ray Absorption Near Edge Structure) XANES techniques, we confirmed the incorporation of cobalt ions into the ZnO structure up to 5 mol.% of Co. Simple annealing of Zn/Co-ZIF-8 materials in the air led to the formation of oxide nanoparticles of about 20–30 nm, while additional treatment of ZIFs with silicon source resulted in nanoparticles of about 5–10 nm covered with protective silica layer. We revealed the incorporation of oxygen vacancies in the obtained ZnO nanoparticles using FTIR analysis. All obtained samples were comprehensively characterized, including analysis with a synchrotron radiation source.

The effect of laser pulse energy on ZnO nanoparticles formation by liquid phase pulsed laser ablation

Zinc Oxide nanoparticles were prepared using pulsed laser ablation process from a pure zinc metal placed inside a liquid environment. The latter is composed of acetyltrimethylammonium bromide (CTAB) of 10−3 molarity and distilled water. A Ti:Sapphire laser of 800 nm wavelength, 1 kHz pulse repetition rate, 130 fs pulse duration is used at three values of pulse energies of 0.05 mJ, 1.11 mJ and 1.15 mJ. The evaluation of the optical properties for the obtained suspension was applied through ultraviolet–visible absorption spectroscopy test (UV/VIS). The result showed peak wavelengths at 210 nm, 211 nm and 213 nm for the three used pulse energies 0.05 mJ, 1.11 mJ and 1.15 mJ respectively. This indicates a blue shift, which means smaller sizes of prepared nanoparticles, correlated with the decrease in laser energy. The blue shift in the absorption edge refers to the quantum confinement property for the produced nanoparticles. In addition, Fourier Transform Infrared Spectroscopy (FTIR) analysis was utilized to confirm zinc oxide nanoparticles formation represented by the absorption values at 435–445 cm−1. The shape and morphology of ZnO nanoparticles were characterized with scanning electron microscope (SEM).

PARTHENIUM MEDIATED SYNTHESIS OF ZINC OXIDE NANOPARTICLES AND ITS CHARACTERIZATION

Objective: To biosynthesize zinc oxide nanoparticles by using parthenium hysterophorous plant extract as a reducing agent and its characterization by spectroscopic techniques.Methods: A novel method was developed to prepare zinc oxide nanoparticles by using zinc nitrate as a precursor and biosynthesis of zinc oxide nanoparticles was mediated by parthenium hysterophorous plant extract without the aid of external energy (high pressure and temperature). This new method involves simple techniques such as centrifugation, filtration, and stirring. Zinc oxide nanoparticles formation was confirmed by analytical techniques such as UV-Visible spectroscopy, powder X-ray diffraction (XRD), Raman spectroscopy and by scanning electron microscopy (SEM) analysis.Results: Zinc oxide nanoparticles were synthesized by using parthenium hysterophorous plant extract as a reducing agent. The XRD measurement showed that zinc oxide nanoparticles possess a typical hexagonal structure and the crystallite size of the synthesized zinc oxide nanoparticles was found to be 32 nm calculated by scherrer’s formula. The SEM images show agglomeration of zinc oxide nanoparticles that are spherical clusters. The maximum absorbance (380 nm) of UV-Visible spectroscopy further confirmed synthesized nanoparticles are zinc oxide. The Raman spectra show both E2 mode and E1 mode, which indicates that the prepared zinc oxide nanoparticles possess crystalline nature with hexagonal wurtzite structure.Conclusion: A method was established to prepare zinc oxide nanoparticles with parthenium hysterophorous plant extract which is a novel approach without the aid of external energy (high pressure and temperature), and formation of zinc oxide nanoparticles was confirmed by spectroscopic techniques. This method can be used in pharmaceutical industry for the synthesis of an antimicrobial agent.

Gas Phase Chemical Evolution of Uranium, Aluminum, and Iron Oxides

We use a recently developed plasma-flow reactor to experimentally investigate the formation of oxide nanoparticles from gas phase metal atoms during oxidation, homogeneous nucleation, condensation, and agglomeration processes. Gas phase uranium, aluminum, and iron atoms were cooled from 5000 K to 1000 K over short-time scales (∆t < 30 ms) at atmospheric pressures in the presence of excess oxygen. In-situ emission spectroscopy is used to measure the variation in monoxide/atomic emission intensity ratios as a function of temperature and oxygen fugacity. Condensed oxide nanoparticles are collected inside the reactor for ex-situ analyses using scanning and transmission electron microscopy (SEM, TEM) to determine their structural compositions and sizes. A chemical kinetics model is also developed to describe the gas phase reactions of iron and aluminum metals. The resulting sizes and forms of the crystalline nanoparticles (FeO-wustite, eta-Al2O3, UO2, and alpha-UO3) depend on the thermodynamic properties, kinetically-limited gas phase chemical reactions, and local redox conditions. This work shows the nucleation and growth of metal oxide particles in rapidly-cooling gas is closely coupled to the kinetically-controlled chemical pathways for vapor-phase oxide formation.

Biogenic manganese oxide nanoparticle formation by a multimeric multicopper oxidase Mnx

Bacteria that produce Mn oxides are extraordinarily skilled engineers of nanomaterials that contribute significantly to global biogeochemical cycles. Their enzyme-based reaction mechanisms may be genetically tailored for environmental remediation applications or bioenergy production. However, significant challenges exist for structural characterization of the enzymes responsible for biomineralization. The active Mn oxidase in Bacillus sp. PL-12, Mnx, is a complex composed of a multicopper oxidase (MCO), MnxG, and two accessory proteins, MnxE and MnxF. MnxG shares sequence similarity with other, structurally characterized MCOs. MnxE and MnxF have no similarity to any characterized proteins. The ~200 kDa complex has been recalcitrant to crystallization, so its structure is unknown. Here, we show that native mass spectrometry defines the subunit topology and copper binding of Mnx, while high-resolution electron microscopy visualizes the protein and nascent Mn oxide minerals. These data provide critical structural information for understanding Mn biomineralization by such unexplored enzymes.

Green Synthesis of Iron Nanoparticles from Selected Plant Materials of Peninsular India

Plant extracts based synthesis of nanoparticles gained attention because of ecofriendly nature. Ability of water extract of locally available plant materials in the formation of iron oxide nanoparticles were screened in the present study. Plant extracts were mixed with ferric chloride solution for the synthesis of nanoparticles. Among the nanoparticles, those derived from the leaf extract of Syzygium aromaticum, Bauhinia natalensis, Artocapus hirsutus, and Anacardium occidentale reported first through this study. Surface plasmon resonance of the nanoparticles characterized, and each nanoparticles had unique absorption maxima. Elemental compositions of particles were revealed through energy dispersive X-ray spectroscopy. It is noticed that phenolics content in the reaction mixture decrease during formation of nanoparticles. This indicate putative role of hydroxyl group present in the phenolics as priming agent of iron oxide nanoparticles formation via reduction of Fe3+ to Fe2+ during green synthesis.