Papers by Keyword: Metal Oxide

Abstract: Ni_1-2xMg_xCu_xO and Ni_1-2xMg_xRu_xO nanoparticles (x = 0.005, 0.01, 0.02, 0.04, 0.08) were synthesized by the chemical co-precipitation method using salt chloride precursor and EDTA as a capping agent.The present work compares the impact of (Mg, Cu) and (Mg, Ru) co-dopants on the dielectric properties of NiO within a frequency range 0.1 -8 MHz and various dopant concentrations x = 0, 0.005, 0.01, 0.02, 0.04, 0.08. The dielectric properties and phase formation were investigated via an impedance analyser and XRD, respectively. X-ray diffraction patterns confirm the successful synthesis and crystallization of all Ni_1-2xMg_xCu_xO and Ni_1-2xMg_xRu_xO nanoparticles in the fcc structure except for Ni_0.92Mg_0.04Ru_0.04O and Ni_0.84Mg_0.08Ru_0.08O nanoparticles confirming a secondary RuO₂ pahse. Observed and calculated data from the impedance analyzer showed higher dielectric constants, ac conductivity, energy loss, and refractive index values for Ni_1-2xMg_xCu_xO than for Ni_1-2xMg_xRu_xO nanoparticles. However, the impedance values of (Mg, Ru) dual-doped NiO nanoparticles were higher compared with (Mg, Cu) dual-doped NiO nanoparticles. Both samples showed a decrease in dielectric constants, impedance, loss tangent, and refractive index as frequency increased (0.1-7.5MHz), with a vice versa behavior as dopant concentration rose, except for the impedance. Hence, Ni_1-2xMg_xCu_xO and Ni_1-2xMg_xRu_xO nanoparticles are good candidates for electrical and optical 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 amount of energy consumed is rising daily, which is swiftly depleting the availability of fossil fuels. Because fossil fuels release warming gases into the environment, they have several negative environmental consequences and contribute to global warming. To fulfill the growing demand for high-quality biodiesel, one practical solution is to employ metal: oxide nano-catalysts in transesterification of animal or vegetable oils. this review outlines into the prevalence of various metal oxide nanocatalysts, such as magnesium oxide, calcium oxide, nickel oxide, zinc oxide, and titanium dioxide, which have recently gained popularity as a means to accelerate the production of sustainable biodiesel. Converting typical metal oxide heterogeneous catalysts into nanoparticles enhances their surface configuration, porosity, crystallinity, chemical and thermal stability, and porosity. Metallic oxide nanocatalysts help make more biodiesel by lowering the reaction temperature and length and speeding up the transesterification reaction. Metal oxide nanoparticles assist in the production of biodiesel, which meets international standards and is of exceptional quality. As a result, the metal oxide nanocatalyst may be further optimized as a promising contender for the global energy business in the future.

Abstract: Manganese dioxide-modified montmorillonite (MnO₂/MMT), a one-step hydrothermal procedure was utilized for fabricating the composites. The structure, morphology and the particulars of the components were explained by XRD, SEM and BET, which proved that MnO₂/MMT composites were successfully synthesized. Conclusions of the experiment show that the adsorption efficiency of MnO₂/MMT reached 99.63% after 5 hours of adsorption for Cr(VI) solution, which was considerably greater than that of the unmodified montmorillonite under the same conditions. The above study highlights how MnO₂/MMT can be used in the wastewater treatment.

Abstract: The nanosized samarium doped tin oxide in varying concentration (0%, 0.5%, 1%, 3%, 5%) was successfully synthesized using the wet chemical precipitation approach. X-ray Diffraction (XRD) analysis was done to monitor the effect of the dopant concentration to the host lattice as broadening and narrowing of the formed peaks are seen. Average crystallite sizes of the produced sample are ranging from 9-28 nm, confirming it to be nanoscale. Identified peaks with Miller indices of ((110), (101), (200), (111), (211), (220), and (002) signifies a tetragonal rutile structure of the synthesized samples. Scanning Electron Microscopy (SEM) shows the difference in morphology for the powdered samples as per different samarium loading as well as the shape, which is granular. Energy Dispersive X-ray spectroscopy (EDX) affirms the successful integration of the samarium dopant to the lattice structure of the SnO₂.

Abstract: The development of the supercapbattery has become the focus of energy storage research due to their potential to increase energy and power density. This research is focused on developing a modification of silicon (Si) porous as an anode with Al₂O₃/CuCrO₂/AC composite as a cathode of supercapacitor. These electrodes were synthesized using LA133 binder with deionized water as solvent. The supercapacitor electrode uses an aluminum foil substrate, while the Si electrode uses a cupper foil substrate. The structural and morphological characterization of the electrodes were identified through XRD, FTIR, and SEM tests, while the electrochemical performance characterization using Galvanostatic Charge-Discharge (GCD) instruments. The results of XRD data analysis of thin film electrodes of supercapacitor showed diffraction peaks which indicated the phases Al₂O₃/CuCrO₂/AC and Si porous. The absorption functional groups of Al₂O₃/CuCrO₂/AC and Si porous were identified through FTIR characterization. The results of SEM showed the addition of CuCrO₂ and structure modification of silicon into porous caused increasing value of porosity. The electrochemical performance of the optimum point at Al₂O₃/CuCrO₂/AC condition, showing a specific capacitance of 50.3 F/g, an energy density of 36.499 Wh/kg, and a power density of 433.6 W/kg. The combination of Al₂O₃/CuCrO₂/AC//Si Porous 16 for supercapbattery devices shows performance with a specific capacitance of 14.4 F/g, an energy density of 6.1 Wh/kg, and a power density of 33.6 W/kg. These results indicate an increase in electrochemical performance compared with Si anodes without modification.

Abstract: Rare-earth-based nanocomposites are currently attracting extensive research interest in biology, medicine, physics, chemistry and material science owing to their optical, electrical and electronic properties, their stability and novel applications. Rare-earth based nanomaterials, especially rare earth oxides (Yttrium oxide, Gadolinium oxide, lanthanum oxide, cerium dioxide, etc.) have fascinated people's devotion owing to their good environmentally friendly and redox properties characteristics. Rare-earth based nanomaterials with exceptional electrochemical properties can be attained by simple, low-cost, environmentally friendly approaches such as hydrothermal/solvothermal method, electrodeposition method, atomic layer deposition method, etc. The electrochemical and microstructures properties of the samples were characterized by X-ray diffraction, scanning electron microscopy, galvanostatic charge/discharge cycling, potentiostatic electrochemical impedance spectroscopy and cyclic voltammetry, in this review, we present a wide-ranging explanation of synthesis methods, morphology and electrochemical performance of numerous rare-earth based nanomaterials used in supercapacitors. We present in this review a brief overview of the recent and general progresses in their functionalization and synthesis.

Abstract: Metal oxide-based gas sensors, have been used in the detection of gaseous pollutants emitted from motor vehicles, such as CO, SO₂, NH₃, NOx, hydrocarbons (HC) etc. However, the problems that up to now are still faced by the metal oxide-based sensors are reviews their low sensitivity, low selectivity and lack of stability. Therefore, it is difficult, to the make such an accurate metal oxide-based sensor and stable over a long period of time. In this short review, it will be described the state-of-the-art technology, design and fabrication methods and various techniques that can be applied to improve the performance of metal oxide-based sensors. Keywords: gaseous pollutants, the motor vehicle emission, gas sensors, metal oxide

Abstract: ZnO:Graphene Oxide composite nanopowders have been successfully prepared by sol-gel method. The study of composite preparation is discussed in this paper. Graphene oxide was added in two ways in order to study the mixed behaviour especially in photocatalytic properties. The degradation of methylene blue (MB) concentration in water was used to evaluate the photocatalytic property under low UV-light irradiation (14 μW/cm²). The results showed that all varian ZnO-GO composite samples have spherical morphology and hexagonal wurtzite crystal structure. An addition of graphene oxide (GO) in ZnO precursor solution during preparation shows a better photocatalytic property that related to reducing in particle size, thereby produce a large surface area and formed a better interfacing with GO/rGO. The existence of GO around ZnO nanoparticles gives some advantageous due to presences of hydroxyl component that directly relate to the increments in photocatalytic behavior. The photodegradation rate of MB in water using ZnO-GO composite as catalyst is significantly increase compared with pure ZnO.

Abstract: Aluminum doped ZnO crystal powders have been successfully prepared by sol-gel method with low temperature (150°C) crystallization process. The AlNO₃ as material dopant were varied by 0.5 wt% and 1.0 wt% relate to 5 mmol of zinc acetate dihydrate as precursor. Degradation of the methylene blue (MB) was used to evaluate the photocatalytic property. The results showed that all ZnO samples have spherical morphology with hexagonal wurtzite crystal structures. The ZnO powder with 0.5 wt % of aluminum has a better photocatalytic property that related to the optical characteristics. The optimum of Al content (0.5wt%) reduces the crystallite size and give some advantages in optical characteristics that directly relate to the increments in photocatalytic behavior. The photodegradation rate of Al doped ZnO 0.5 wt% is increase almost 100% compared with ZnO undoped. The stability and reusability of 0.5 wt% Al doped ZnO as photocatalyst, is also observed by monitoring the photocatalytic behavior under 14 hours irradiation (in three recycle used)