22 research outputs found
Structural and improved dielectric properties of Bismuth pyrochlores containing interchangeable Ta5+ and Nb5+ cations
Get PDFThe pyrochlore structure demonstrates great structural flexibilities, compositional variables, and diverse electrical properties suitable for various electrical applications. This study aimed to synthesise novel pyrochlore phases with improved dielectric performance in the Nb-doped bismuth magnesium tantalate (BMT) system. A complete subsolidus solution was successfully prepared by solid-state reaction through a one-to-one replacement of Ta5+ by Nb5+ with the proposed chemical formula of (Bi3.50Mg0.50)(Mg1.30NbxTa2.70-x)O13.80 (0.00 ≤ x ≤ 2.70). Such doping mechanism implies that both isomorphous Nb5+ and Ta5+ are highly interchangeable due to their similar crystallo-chemical structures and ionic radii. The incorporation of Nb5+ into the BMT host structure resulted in the gradual increase of lattice parameters from 10.5610 (9) to 10.5809 (10) Å. The well-connected polyhedral grains in the range of 2.25–20.00 μm supported their average relative densities of above 80%. The Nb dopant was concluded to significantly enhance the dielectric performance of BMT pyrochlores, i.e., more than two-fold increase of dielectric constant, ε' from 81 to 195, while dielectric loss, tan δ is retained low in the order of 10-3 © 2024 Malaysian Institute of Chemistry. All rights reserved
Novel synthesis of Cu2ZnAl2O4 nanostructures for photocatalytic and electrochemical sensor applications
No full textHybrid nanostructured materials currently offer a potential approach for a variety of applications due to improvements in their physio-chemical characteristics. Techniques for XRD, TEM-HRTEM, SAED, and UV-DRS were used to characterize the Cu2ZnAl2O4 (CZA) material. Without any secondary phases and with an average crystallite size of 40 nm, X-ray diffraction pattern examination demonstrates the increased crystalline structure. A highly crystalline, polydisperse CZA nanostructure was visible using TEM-HRTEM and SAED. The CZA nanostructure's light-absorbing behavior is presented by UV-DRS analysis, which found that the predicted bandgap energy was 5.0 eV. In this article, we describe an easy chemical synthesis of a hybrid CZA nanostructure that works well as a catalyst to break down the acid red 88 (AR-88) dye under UV, sunlight, and low light conditions. Additionally, it was studied to determine how to modify the working electrode's surface to enable the detection of lead and tin metal ions. With 93.1% of degradation and comparison work on decolorizing AR-88 dye in the presence of both sunlight and darkness, CZA nanostructure was looked at as a potential catalyst for the decolorization of AR-88 dye. By using graphite electrode paste and cyclic voltammetry to analyze the synthesized sample in 1 N KCl, it was discovered that it had outstanding redox reaction and lead and tin detection capabilities
A review on environmentally benevolent synthesis of CdS nanoparticle and their applications
No full textThe word ‘Nano’ received great attention of world, due to their fabulous and novel applications in numerous fields. Cadmium sulphide nanoparticles (CdS NPs) are unique in their properties due the size and shape, and are popular in the area of biosensor, bio-imaging, nano-medicine, molecular pathology, antimicrobial activities, photovoltaic cells, semiconductor, and drug delivery, etc. Due to its fascinating applications, it was synthesized using several methods and explored for its all possible applications. The most affordable, efficient, friendly and biocompatible way of creation of CdS NPs is biogenic synthesis using microorganisms such as bacteria, fungus, algae, enzymes, proteins and parts of plants. In biogenic synthesis of CdS, cadmium undergoes bio-reduction by the variety of natural products present in microorganism as well as in plants. In present review, inclusive study was piloted on the nano-synthesis, characterization and various applications of CdS NPs made using different plant sources and microorganism
Lanthanum Doped Strontium Titanate Nanomaterial for Photocatalytic and Supercapacitor Applications
No full textElectrochemical sensor of carboxymethyl cellulose and photocatalytic degradation of Navy Blue dye by sonochemically synthesized Titanium oxide nanoparticles
No full textNanocrystalline titanium oxide nanoparticles (TiO2 NPs) were synthesized by using a low-cost sonochemical method. TiO2 NPs exhibited anatase phase and an average crystallite size of 40.64 nm, according to a powder X-ray diffraction (PXRD) investigation. SEM and TEM images revealed spherical shape, with asymmetric geometries for TiO2 NPs. The micrographs thoroughly corroborated the plate-like structure for the NPs. In order to confirm the average energy gap of TiO2 NPs, diffused reflectance spectroscopy (DRS) via Kubelka-Monk function was applied (3.66 eV). Navy blue dye was used to study the photocatalytic properties of NPs and discovered to be triggered at 590.9 nm. The photodegradation rate of NB dye decolorized up to 74.04% after 120 min of UV light exposure. The first order kinetics was indicated by a linear relationship between log C/Co and k. The demonstrated rates of photodecoloration for NB under UV light in the presence of scavengers AgNO3, ethanol, and ethylenediamine tetraacetic acid (EDTA), were found to be 65.50%, 61.46%, and 57.33%, respectively. Using the carbon paste electrodes and cyclic voltammetry (CV) in 0.1 N HCl solution, the electrochemical characteristics of the obtained sample were studied. The carboxymethyl cellulose sensor made from TiO2 NPs demonstrated a remarkable sensitivity of 0.08 A. The results showed a high recovery for lead with low% of RSD values. The TiO2 electrode is a promising electrode material for sensing applications due to its outstanding electrochemical performance
Green Synthesis of Ni-Cu-Zn Based Nanosized Metal Oxides for Photocatalytic and Sensor Applications
No full textThe preparation, characterization, and application of Nickel oxide (NiO)–Copper oxide (CuO)–Zinc oxide (ZnO) transition nanometal oxides have significantly enhanced their tunable properties for superior multifunctional performances compared with well-known metal oxides. NiO–CuO–ZnO nano transition metal oxides were synthesized by a simple eco-friendly solution combustion method. X-ray diffraction studies revealed distinct phases such as monoclinic, cubic, and hexagonal wurtzite for CuO, NiO, and ZnO, respectively, with NiO having the highest composition. The particle sizes were found to be in the range between 25 and 60 nm, as determined by powder X-ray diffraction. The energy bandgap values were found to be 1.63, 3.4, and 4.2 eV for CuO, ZnO, and NiO, respectively. All metal oxides exhibited a moderate degradation efficiency for AR88 dye. The results of ultraviolet–visible absorption spectra helped identify the bandgap of metal oxides and a suitable wavelength for photocatalytic irradiation. Finally, we concluded that the electrochemical studies revealed that the synthesized materials are well suitable for sensor applications
A Comparative Cyclic Voltametric Study on Rare Earth (Eu, Sm, Dy, and Tb) Ions Doped La10Si6O27 Nanophosphors for Sensor Application
No full textThe rare earth (RE = Eu, Sm, Dy, and Tb) ions doped La10Si6O27 nanophosphor was synthesized by a simple solution combustion method. The prepared La10Si6O27:RE3+ nanophosphors (LNPs) were subjected to diverse technical tools for exploring their structural, optical, morphological, and electrochemical features. The structural analysis using powder X-ray diffraction (PXRD) patterns revealed the hexagonal oxy apatite phase for LNPs with a crystallite size in the range of 25–50 nm, and the equivalent was affirmed by image analysis via transmission electron microscopy (TEM). Utilizing DRS data, the bandgap energy (Eg) values were recorded for LNPs. Cyclic voltametric (CV), electrochemical impedance spectroscopy (EIS), and sensor studies were performed using a modified carbon paste electrode of LNPs. The modified LNP electrodes were found to be highly effective in sensing paracetamol in acidic medium with a quick response time of 3 secs for sensing the drugs at 1 mM concentration. All the RE ions Eu3+, Sm3+, Dy3+, and Tb3+ (5 mol%)-doped LNPs exhibited the most promising electrochemical sensing characteristics
Electrical circuit modeling for the relaxor response of bismuth magnesium tantalate pyrochlore
Get PDFThe electrical properties of bismuth magnesium tantalate pyrochlore, Bi3.30Mg1.88Ta2.82O13.88 (BMT) were investigated by both inductor-capacitor-resistor (LCR) and impedance spectroscopy techniques covering a broad temperature range of 10–1073 K and a frequency range of 5 Hz - 1 MHz. At below ∼180 K, BMT pyrochlore exhibited interesting relaxor behaviour that showed high dispersion characteristics in its frequency-temperature dependent dielectric constants, ε′ and dielectric losses, tan δ, respectively. The maximum ε′max of ∼77 was obtained at the temperature maximum, Tm of 154 K. The frequency-independent ε′ data above 154 K at a fixed frequency of 1 MHz can be well fitted with the Curie-Weiss law and the relaxation features of Bi3.30Mg1.88Ta2.82O13.88 obeyed the Vogel-Fulcher equation. The dielectric properties of Bi3.30Mg1.88Ta2.82O13.88 relaxor in the low temperature range of 20–320 K could be satisfactorily modeled with different equivalent circuits. In this perspective, a master circuit consisting of a parallel R-C-CPE element in series with a capacitor was required to accurately fit the low temperature data
Microstructural and dielectric properties of Mo-doped barium strontium titanate nanopowders
No full textThe goal of this research was to examine how the dielectric properties of barium strontium titanate (BST) differ from those of BST that has been doped with molybdenum. The slow injection sol-gel technique was used. The addition of Mo6+ ions into the lattice of BST caused reduction of the mean crystallite sizes of BST, from 19.35 nm to 17.84 nm. Similarly, the mean particle size decreased from 26.02 nm all the way to 18.58 nm following the addition of Mo within the BST structure. Ultimately, the dielectric constant of BST was elevated with a maximum value of 946.3 at 1 MHz as compared to the value of 233.8 for BST. After Mo was added to BST, a reduction in dielectric loss (0.15576 to 0.0356) was also attained. Because of this, the Mo dopant in BST has significantly altered its microstructural and dielectric properties, making it suitable for multiple applications.</p
