Papers by Keyword: Nanoparticles

Abstract: Phase components of experimental low cost titanium alloys, their substructure and parameters, dislocation structure, features of phase formation in the metal, which differ in alloying systems, were studied using complex research methods. The stoichiometric composition of dispersed phases in the internal volumes of alloy grains was determined by diffraction patterns using transmission electron microscopy. It is shown that in the structure of titanium alloy Ti-2,8Al-5,1Mo-4,9Fe there are dispersed nanoparticles of intermetallic phases of different morphology and stoichiometric composition. These are the phases: Ti₃Al and Fe₂Ti with a size of 10…40 nm; Mo₉Ti₄ - 20…120 nm. Studies of titanium alloy Ti-1,5Fe-O showed the presence in the structure of mainly nanoparticles of oxides: Ti₃O₅ size 10…30 nm and Ti₄Fe₂O, FeTiO₅ (10…90 nm), as well as intermetallics Fe₂Ti (10…40 nm). It is established that the formation of nanoparticles of intermetallic and oxide phases in the thin plate structure of the investigated experimental low cost titanium alloys promotes the formation of the substructure with uniform distribution of dislocation density. This provides a high level of mechanical properties of alloys.

Abstract: Ice slurry offers a promising solution for enhancing energy efficiency and environmental sustainability in industrial refrigeration and thermal energy storage applications. This review critically examines the effects of additives and production methods on the thermo-physical properties of ice slurry, focusing on viscosity and heat transfer performance. Additives such as ethylene glycol (6.5–10.3%), sodium chloride (up to 9%), and propylene glycol (5–24%) significantly enhance heat transfer coefficients by up to 33%, while alumina-based nanofluids (0.2 wt%) increase thermal conductivity by as much as 67%. Optimal ice packing factors (10–25%) and advanced production techniques, including direct contact and fluidized bed methods, improve energy efficiency, scalability, and operational reliability while mitigating issues such as particle agglomeration and viscosity rise. The study emphasizes rigorous methodological transparency with explicit equation definitions, controlled variables, and standardized measurement units (e.g., W/m²K for heat transfer, kg/m·s for viscosity). These findings provide valuable insights to guide the development of robust, high-performance ice slurry systems for large-scale cooling and energy storage applications.

Abstract: Zinc oxide is the most widely used nanomaterial in nanotechnology due to its outstanding properties and characterizations. Enormous attention has arisen due to its unique physical properties consists of a wide energy band gap of 3.37 eV at ambient temperature and large binding energy of 60 meV, which give development to an extensive range of potential applications in many areas such as electronics, solar cells, and biological applications. The size and shape of nanoparticles are significant to ensure the process becomes faster, cheaper and more efficient compared with traditional methods. By having more active area of nanoparticles, the biological and chemical process become more effectives. The biological activity of ZnO Nanoparticles was investigated through the antibacterial activity, anti-microbial activity, as anticancer and antioxidant material. The method used to prepare the ZnO Nanoparticles also take an important part which is to reduce the by-product formation when applied in wastewater treatment. This article summarizes different preparation methods of ZnO Nanoparticles and its application uses. The ZnO nanoparticles can be used the various applications, for example for the antibacterial, anti-cancer, anti-microbial, antioxidant and for wastewater treatment applications.

Abstract: The modification of titanium dioxide (TiO₂) with zirconium dioxide (ZrO₂) supported by chitosan (CS) was carried out to obtain a binary oxide system, which should have the properties of both components such as high stability, solar propulsion, non-toxicity and good corrosion resistance. The sample with a ratio of 1:1:3 (TiO₂:CS:ZrO₂) showed the best results with a photocatalytic degradability of 99 % after 90 minutes at a pH of 7 and in 10 ppm Malachite Green (MG). Under visible light, the photocatalytic degradability of the CS/TiO₂-ZrO₂ hybrid was more than 90 %. The enhanced photocatalytic degradation of MG by hybrid catalyst beads was attributed to the synergistic effect of hybrid CS/TiO₂-ZrO₂.

Abstract: Ni and Ni-containing nanoparticles exhibit promising magnetic properties. In a preliminary experiment, these nanoparticles aggregated after synthesis. Because nanoparticle aggregation may degrade their unique properties, a method to prevent their aggregation is required. In this study, Ni-Pt nanoparticles were synthesized and coated with silica to suppress aggregation. A colloidal solution of Ni-Pt nanoparticles was synthesized in water exposed to air using nickel(II) acetate tetrahydrate (Ni source), hexachloroplatinate(IV) hexahydrate (Pt source), sodium borohydride (reducing agent), and citric acid (stabilizer). Silica-coated Ni-Pt nanoparticles (Ni-Pt/SiO₂) were synthesized by adding a tetraethylorthosilicate (TEOS)/ethanol solution to the colloidal Ni-Pt nanoparticle solution. The morphology of the Ni-Pt nanoparticles varied with reaction time. The Ni-Pt/SiO₂ nanoparticles consisted of Ni-Pt cores and SiO₂ shells, with their morphology dependent on the TEOS concentration. Furthermore, the Ni-Pt/SiO₂ nanoparticles were more dispersed than the uncoated Ni-Pt nanoparticles, suggesting that the silica coating suppressed aggregation.

Abstract: Zinc oxide (ZnO) is a common photocatalyst for dye degradation, but its efficiency is limited by surface properties, photocorrosion, and pH sensitivity. This study functionalized ZnO with 2-aminophenol (ZnO-AP) to enhance dye adsorption and stability under varying pH. FTIR, XRD, and UV-Vis confirmed successful synthesis, with ZnO-AP showing a reduced band gap for improved visible light absorption. Photodegradation tests using Brilliant Blue G (BBG) revealed that ZnO-AP has the highest efficiency (36.17%) at pH 4, driven by strong electrostatic interactions. Performance decreased at pH 7 and 11 due to reduced dye adsorption, especially at basic pH with electrostatic repulsion. Functionalization also protected ZnO against photocorrosion, improving stability in acidic conditions. These results highlight 2-AP functionalization as a promising strategy to enhance the photocatalytic performance of ZnO across pH ranges.

Abstract: Copper sulphide (Cu₂S) is an indirect gap p-type semiconductor belonging to I-VI group. The wet chemical route was used to synthesize manganese (Mn) doped copper sulphide nanoparticles with a decrease in particle size by increasing the concentration of manganese element. These nanoparticles were analyzed by using the various characterization techniques like ultraviolet-visible (UV) absorption spectroscopy, photoluminescence (PL) spectroscopy and transmission electron microscopy (TEM). The dip coating method was used to prepare Mn doped Cu₂S thin films on fluorine doped tin oxide (FTO) glass slides with varying the dip time. These thin films were heat treated in air atmosphere at 420°C for 20 minutes and investigated by using the various analysis techniques like scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive analysis by X-rays (EDAX) and mapping. The detailed explanation of obtained experimental results is discussed in this paper.

Abstract: Utilising an uncomplicated, environmentally friendly strategy to synthesise nanoparticles presents a prospective substitute for dangerous chemical and expensive physical techniques. Therefore, this study was initiated with the objectives of synthesising Co₃O₄ nanoparticles using a facile green route and evaluating their magnetic properties and photocatalytic activities. Spherical Co₃O₄ nanoparticles with dimensions ranging from 8 to 32 nm were successfully produced using garlic extract. Magnetic analysis revealed weak ferromagnetism at low temperatures, with a coercive field of 14×10^-4 T. This low-temperature weak ferromagnetism may be attributed to uncompensated surface spins that form a short-range ordered cluster of spins. However, inside the sample, an antiferromagnetic exchange interaction occurs between non-magnetic tetrahedral Co²⁺ ions and magnetic octahedral Co³⁺ ions. Consequently, an exchange bias field of approximately 8.76 ×10^-4 T was observed. Above the Néel temperature, the thermal energy overcomes the antiferromagnetic ordering, resulting in paramagnetic behaviour at room temperature. Furthermore, the photocatalytic activity of the green synthesised Co₃O₄ nanoparticles demonstrated 55% degradation of methyl orange (MO) dye within 90 minutes. However, more efficient degradation (63% degradation within 90 minutes) of MO was achieved in the presence of a small amount of NaBH₄, which typically functions as a source of electrons to enhance the degradation rate. The photocatalytic (dye degradation) activity of these green synthesised room temperature paramagnetic Co₃O₄ nanoparticles could be applicable for water purification processes.

Abstract: This paper reports melting temperature depression (MPD) for nano particle using different melting models reported in the literature such as: Liquid drop model, Surface phonon instability model, Gibbs Thomson equation, and Semi-empirical model etc. Reduced particle size is associated with a significant decrease of melting temperature. For bigger nanoparticles of all forms taken into consideration, the behaviour of melting temperature is identical, while for small nanoparticles, it differs dramatically. The effect of the shapes on melting point during the depression of nano particles has also been calculated for different shapes like film, icosahedron, wire, spherical, hexahedron, octahedron and tetrahedron. It has been discovered that the shape of the particle affects the lead, silver, gold, and aluminum nanoparticles' melting temperatures. Melting temperature depression is found to be lowest for tetrahedron-shaped nanoparticles and largest for thin films.

Abstract: The Silver-graphene oxide (AgGO) nanocomposite is highly regarded for controlling the biological activity of silver nanoparticles (AgNPs). Combining AgNPs with Graphene Oxide (GO) offers better stability than single AgNPs. Traditional chemical synthesis methods use toxic reducing agents, posing environmental risks. This study aims to synthesize AgGO nanocomposite using a green synthesis method with chives (Allium tuberosum) extract as a reducing and stabilizing agent. The reducing properties of chives extract are attributed to its sulfur-containing compounds play a crucial role in the reduction of silver ions to silver nanoparticles. AgGO nanocomposite was synthesized with different chives extract concentrations (0.5 M, 1.1 M, and 2.0 M) and confirmed using UV-Visible spectrometer, X-Ray Diffraction (XRD), and High-resolution transmission electron microscopy (HRTEM). The 1.1 M concentration was the most efficient, forming AgNPs at 430 nm with an average particle size of 18 nm. The antibacterial activity against E. coli and S. aureus was assessed, revealing that AgGO-1.1 has significant antibacterial capabilities comparable to pure AgNPs.