Papers by Keyword: Wet Chemical Method

Abstract: In this study, doped ytterbium oxide (Yb₂O₃) nanoparticles (NPs) with different dopant type (Eu and / or Tb) and undoped were synthesized by wet chemical method using nitrate salt as a starting source. Afterwards, they were calcined at 900 °C for 4 h. The crystal structure phase, size, and morphology of undoped and doped Yb₂O₃ nanoparticles (NPs) were characterized by X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). Undoped and doped NPs were exhibited cubic bixbyite-type crystal structure (Ia-3 space group). Lattice parameter changes caused by dopant element in NPs were examined using X-ray peak profile analysis. In order to investigate the occuring changes in the crystal structure, average crystallite size (CS) and lattice parameter (LP) values were computed with Williamson–Hall (W–H) and Cohen-Wagner (C–W) methods, respectively. It was observed that the crystal structure of the doped NPs expanded compared to the undoped Yb₂O₃ NPs, which explains the increase in the LP and CS values. The LP values of all the NPs were ranged from 10.444 Å (R² = 94.9) to 10.453 Å (R² = 81.8) while the CS of them were between 19 nm (R² = 95.9) and 24 nm (R² = 88.8). All the NPs exhibited nearly spherical and agglomerate structure and there were also few pores between the agglomerate particles in the structure. Besides, continuous agglomerate morphology formation was observed in particles containing Tb. The average nanoparticle size values were varied between 46 and 115 nm depending on the dopant element.

Abstract: Barium strontium cobaltite (Ba_0.5Sr_0.5CoO_3−δ) nanoparticles were synthesized by using without water and surfactant (WOWS) sol-gel method, co-precipitation method and composite mediated hydrothermal method (CMHM). Co-precipitation synthesis was carried out for 0.4 M precursors solutions of strontium nitrate Sr (NO₃)₂, cobalt nitrate hexahydrate Co (NO₃)₂·6H₂O and barium nitrate Ba (NO₃)₂ and with the sodium hydroxide NaOH as precipitating agent, sol-gel synthesis was done using ethylene glycol as precipitating agent and the CMHM synthesis was done using sodium hydroxide and Potassium hydroxide (NaOH-KOH) as reactants and precipitating agents at 180 °C for 65 min. Calcination of the synthesized samples was done at 830 °C for 02 hours. Pellets of calcined powder was sintered at 850 °C for 20 minutes. X-ray diffraction (XRD) study was used to find the structural parameters (crystal structure, crystallite size and phase purity). The observed phase transformation of pure barium strontium cobaltite monoclinic to orthorhombic structure was found after heat treatment. Crystallite sizes were calculated by using Scherrer’s formula. Temperature dependent (100 to 600 °C) dc conductivities of the sintered pellets were measured and found to be increased with the successive increase in measuring temperature. Temperature dependent (100 to 600 °C) impedances of all samples synthesized through wet chemical methods at fixed frequency of (10kHz) was also measured and compared. The structural and AC/DC electrical properties were correlated to different synthesis methods. The synthesized samples can be thought as an electrode material for intermediate temperature range solid oxide fuel cells (IT-SOFCs).

Abstract: s: In this study, nitrogen-doped ZnO thin films with different nitrogen content were produced by a wet chemical process. The optical properties and the structure of these ZnO films were investigated by LT-PL spectrum, Raman spectrum, SEM and XRD. XRD result showed that the cubic ZnO phase appeared in the 10% nitrogen-doped ZnO films, which might be attributed to the stress in these ZnO film. Moreover, results of SEM measurement proved that the nitrogen atoms were introduced into the lattice of nanoZnO crystal. In addition, LT-PL spectra also confirmed that this new appeared phase was a cubic ZnO phase, due to the lack of the new PL mission peak. Key words: ZnO, wet chemical method, luminescence, XRD

Abstract: A simple, two-step fabrication technique was presented to prepare the Ag/ZnO hybrid nanostructures using silver nitrate and zinc nitrate. Silver particles were synthesized by chemical reduction method and the ZnO layer was coated on the surface of silver using wet chemical method. The microstructure, the composition and the optical properties of the obtained materials were further characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and fluorescence (FL) spectroscopy. The results showed that the silver and zinc oxide composite had been successful prepared. The intensity of fluorescence showed an enhancement of R6G (dye) indicate that ZnO shell had an improvement on the silver metal enhance fluorescence.

Abstract: Cuprous oxide sheet-like particles had been synthesized via a wet chemical treatment of CuSO₄·5H₂O and NaOH in the solution at room temperature for 1 h. The as-prepared Cu₂O sheet-like particles were characterized by X-ray powder diffraction (XRD), Field-emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM). Cu₂O sheet-like particles was determined by these parameters (the amount of polyvinylpyrrolidone (PVP-K30) and reaction time). The possible formation mechanism for the products has been presented. The photocatalytic properties of the as-synthesized samples show the size/shape-dependent properties and potential applications.

Abstract: Wet chemical method was applied to prepare magnesium oxide nanoparticles using magnesium nitrate and sodium hydroxide as precursors in presence of starch as stabilizing agent. The XRD analysis of MgO nanoparticles showed the average particles size of crystallite as 12nm. SEM images also proved the crystalline nature of MgO nanoparticles. Antibacterial studies were done on gram positive (S. aureus) and gram negative (E.coli) bacteria using the above prepared nanoparticles by agar diffusion method. The zone of inhibition was found to more in S.aureus compared to E.coli. Since this method of preparation produced better yield in simple and cost effective way, it can be applied for large scale preparation of magnesium oxide nanoparticles.

Abstract: The manganese sulfide, MnS, is a wide bandgap (Eg = 3.1eV) diluted magnetic semiconductor belonging to the VIIB-VIA family with outstanding magneto-optical properties. The authors report the synthesis and characterization of MnS nanoparticles. The MnS nanoparticles were synthesized by simple wet chemical method at ambient temperature. Manganese acetate (C4H6MnO4.4H2O) was used as source for Mn+2 ions and thioacetamide (C2H5NS) was used as source for S-2 ions. The energy dispersive analysis of X-ray (EDAX) and X-ray diffraction (XRD) were used for stoichiometric and structural characterization of the synthesized nanoparticles respectively. The crystallite size calculated from XRD using Scherrer’s formula and Hall-Williamson relation came out to be of 6.81 nm and 5.27 nm respectively. The optical absorption spectra showed absorption edge at 325 nm corresponding to energy of 3.82 eV, which acknowledged the occurrence of blue shift. The photoluminescence spectra recorded for five different excitation wavelengths viz 250, 275, 280, 300 and 325 nm showed three emission peaks at 463 nm, 550 nm and 821 nm. The TEM and SEM analysis of the particles clearly shows the particles are spherical in shape. The selected area electron diffraction (SAED) pattern showed ring pattern, stating the nanoparticles to be polycrystalline. The obtained results are discussed in details.

Abstract: Commercially available magnesium alloy is extensively used in structural engineering components although, like many magnesium-based materials, it suffers from poor corrosion resistance, particularly in moist environments, which limit wider application. Previously, by reducing the contact area of metal substrate with surrounding water environment and decreasing the risk of corrosion is shown to improve the corrosion resistance of magnesium alloy in humid environments and in the presence of chloride-containing aqueous environments. The objective of this study, without the low-surface-energy materials modification, is to fabricate the superhydrophobic surfaces by wet-chemical methods and to understand how the microstructure influences the surface wettability of unstable materials such as magnesium alloy. The influence of the variety of experiment conditions on the wettability of the substrates was investigated by a contact angle goniometry with water as a probe liquid. Scanning electron microscopy and energy dispersive spectroscopy were used to study the surface chemistry and microstructure at various stages of the multi-wet-chemical process.

Abstract: A novel nanoenergetic material was prepared by filling KNO₃ in the CNTs through a wet chemical method. The samples were characterized by TEM, XRD, and TG/DSC. The results show that KNO₃ with a mean diameter of ~9 nm were homogeneously filled into CNTs to form KNO₃@CNTs nEMs. The TG/DSC curves indicate that the reaction enthalpy (ΔH) of KNO₃@CNTs nEMs was 876.1 J/g and the characteristic temperature of the exothermic peak was 386.8 °C.

Abstract: A new type of ZnO/Ag micro hybrid material has been fabricated by a facile wet chemical method using citrate as a crystal growth modifier. The morphology and component of ZnO/Ag hybrid material were characterized by SEM and XRD. It is shown that the platelike crystals connect together by means of embedding. The sample is composed of wurtzite ZnO and face-centered cubic Ag. The results of XPS, UV-Vis and PL spectra verify the electron transfer from Ag to ZnO. The photocatalytic test with Rhodamine B (RhB) as a representative dye pollutant shows that the ZnO/Ag hybrid material exhibits an improved photocatalytic activity.