جستجوی مقالات مرتبط با کلیدواژه "metal oxides" در نشریات گروه "شیمی"

This study investigates the effects of partial silanization on the properties of zinc oxide (ZnO) and magnesium oxide (MgO) nanoparticles within a resin infiltrant, employing a suite of characterization techniques to understand the implications of this surface modification. Through Fourier-Transform InfraRed (FT-IR) spectroscopy, we confirmed the successful attachment of silane coupling agents to the nanoparticle surfaces, indicating substantial chemical modifications. X-Ray Diffraction (XRD) analysis revealed that these modifications led to an increase in particle size and slight peak broadening, suggesting alterations within the crystal lattice due to the presence of the silane coupling layer. Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS) further demonstrated improved dispersion and reduced agglomeration of the silanized nanoparticles compared to their non-silanized counterparts, highlighting the homogeneous distribution of elemental components such as silicon and carbon. Transmission Electron Microscopy (TEM) provided corroborative morphological details, showing changes in shape and size that align with the findings from FT-IR and XRD, underscoring the physical changes as a direct consequence of the chemical modifications. This multi-technique approach not only illustrates the successful partial silanization of nanoparticles but also underscores its potential to enhance the mechanical and antibacterial properties of resin infiltrants, promising significant benefits for restorative dental applications.

Nanotechnology has achieved significant consideration over time. Nanoparticles are an essential factor of nanotechnology. The particle size of nanoparticles is between 1 and 100 nanometers which are fabricated of organic matter, metal, metal oxides, and carbon. Different methods are used for preparation of nanoparticles such as chemical, biological, and physical methods. The characterizations of nanoparticles show a comparatively greater area of surface vs. the volume, improved steadiness or reactivity and increased mechanical strength. Nanoparticles are innovative materials in science and technology and they have several applications in some fields such as agriculture, medical, electronic, chemical, and pharmaceutical. Nanotechnology is essentially a varied method in which materials are synthesized. Due to their unique properties such as magnetic, mechanical, and optoelectronic, the synthesis of nanomaterial is of high significance. In this review, three metal oxide nanoparticles were explained, including ZnO, CuO, and CeO2, which were prepared by chemical and green methods with various techniques for description of nanoparticles such as UV-Vis spectroscopy, infrared spectroscopy, diffraction of X-ray, microscopy of scanning electron, and microscopy of transmission electron with microscopy of atomic force.

Intrinsically conducting polymers (ICPs) have revolutionized materials science with their versatile applications in electronics, sensors, and energy storage. This review explores the synthesis, properties, and applications of polypyrrole (PPy) and its hybrid nanocomposites with metal oxides, emphasizing advancements in electrical conductivity, stability, and performance. PPy, a prominent conducting polymer, is synthesized through chemical polymerization or electrochemical methods and exhibits high conductivity and mechanical flexibility. Doping PPy with metal oxides like nickel oxide (NiO) and tungsten oxide (WO3) enhances its properties for various applications. PPy-NiO composites show improved conductivity and dielectric properties, while PPy-WO3 composites demonstrate superior electrochemical performance in supercapacitors. This review highlights recent advancements in synthesizing and characterizing these composites, including X-Ray Diffraction (XRD), Ultraviolet-Visible Spectroscopy (UV-VIS), and Raman Spectroscopy. The findings underscore the potential of PPy-metal oxide composites in advancing technologies such as energy storage, corrosion protection, and sensor development.

Three isostructural metal-organic framework materials (MOFs) formulated as M[(HBTC)(H2O)]ˑH2O(M = Cu for 1, Zn for 2 and Ca for 3) constructed with 1, 3, 5-benzenetricarboxylate (BTC) were synthesised under hydro/solvothermal conditions. The three compounds were characterised on the basis of infrared and UV-Vis spectroscopy and the structure of 3 elucidated with the help of single-crystal x-ray crystallography. The UV-Vis spectrum of 1 exhibited a unique band at 511 nm. In the region 520 – 534 nm, the band splits into two moderately intense peaks at 527 and 531 nm. These absorption peaks along with other bands at 629 and 638 nm were assigned to d-d transitions of the copper (II) ion with distorted square planar geometry. The infrared spectra of the three compounds revealed that the ligand, BTC anion coordinated in a chelating and / or bridging mode to the metal center. The presence of absorption bands at 1699 cm-1 in 1 and 2, (1681 cm-1 in 3) can be attributed to protonated HBTC for 1-3. Single-crystal X-ray crystallographic studies of compound 3 revealed well-ordered structure with BTC ligand linking the individual chains to form a network structure. On heating Cu(HBTC)(H2O)ˑH2O up to 400oC, a copper-oxide embedded in carbon matrix was obtained with uniform particles of 10 -100 nm size.

Supercapacitors (SCs) are promising energy sources with high power densities. In the recent years, many efforts have been made to enhance the low energy density of SCs through improvement of the electrode materials. As electrode materials, metal oxides/hydroxides (MOHs) and their composites usually offer high energy densities as a result of their high theoretical capacitances. Up to now, various synthetic methods have been developed for preparing MOHs. In this regards, cathode electrodeposition through base electrogeneration has been intensively used as a one-step simple technique for obtaining various nanostructures of MOHs composites as high-performance SC electrode materials. In this paper, the reports on the fabrication of MOHs-based nanomaterials through the CED method and their super-capacitive abilities have been reviewed.

α-Fe2O3 (hematite) is the most stable iron oxide under ambient conditions. This transition metal oxide has been extensively investigated because it has unique electrical and catalytic properties. In this report, a novel microwave method for preparation of α-Fe2O3 nanoparticles has been developed. The process contained two steps: first, precursor were obtained from a mixed solution of 50 ml of 0.3 M Fe (NO3)2.9H2O and 1.2 g of urea under 540 W microwave irradiated for 6 min. Then, the precursors were calcined at 800 °C to fabricate pure α-Fe2O3 (hematite) nanoparticles for 4 h. Nanoparticles were characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and Energy dispersive X-ray spectrometer (EDX) technique. The results indicate that the morphologies of final products significantly depend on the reaction conditions including the reaction time, the initial concentration of precursor, reagent and calcinations temperature.