Synthesis, characterization, and gas sensing properties of In-doped ZnO nanopowders

Indium (1at %) doped ZnO and ZnO nanoparticles have been synthesized via sol gel method. The structural characters of the synthesized nanoparticles have been studied by X-ray diffraction pattern (XRD), scanning electron microscopy (SEM) and energy-dispersiveX-ray spectroscopy (EDX). From synthesized nanopowders a tablet was prepared by using the isostatic pressing and then sintered at 600°C. Then, the gas-sensing properties of ZnO and IZO powder tablets were evaluated with respect to the acetone gas at different temperatures and concentrations. XRD pattern and SEM images showed the prepared samples were crystallized in the wurtzite structure with the average particle size of 32 and 27 nm. The gas sensing measurement results showed that the indium dopant ions improved the gas sensitivity of ZnO for high acetone concentrations effectively. Therefore, it is suggested that the IZO tablet can act as reliable and low cast gas sensor for acetone detection. Sintering temperature strongly increased the grain size and density of samples. EDX analysis confirmed the presence of indium in zinc oxide structure

The Effect of Annealing Temperature on the Structure and Hardness of Palladium Thin Film

Palladium thin films, with a thickness of about 110 ?, were deposited at room temperature on glass substrates, by electron beam evaporation method, and subsequently annealed at 523, 598, 673, 748, 773, 798 and 823 K for an hour, and then were cool down slowly. The structure and hardness of the thin films were investigated using X-Ray Diffraction (XRD) and Vickers Micro Hardness (MHV) analysis respectively. XRD patterns showed that the structure is amorphous before annealing and as the annealing temperature increases, the structure of Pd thin films become crystallized gradually. The Vickers Micro Hardness modifications of the Pd thin film showed that the heat treatment resulted in the structural compression of the sample and therefore the density increased compared to the preheating temperature. Thus, by heating up to the re-crystallization temperature, the Pd thin film-tensile strength increased, which is itself due to the mechanical behaviour of the material, and has a significant effect on its efficiency. So we realized that the hardness of the thin films is directly affected by annealing temperature

Infrared Spectroscopy Studies on sol-gel prepared alumina Powders

Gamma-alumina fine particles were synthesized by sol-gel process. Aluminum tri-sec-butoxide (ATB), anhydrous ethyl alcohol (EtOH), water (H2O) and hydrochloric acid (HCl) were used as starting materials. Different samples were synthesized with EtOH/ATB=60/1, HCl/ATB=0.08/1 and H2O/ATB=1/1 ratios and calcined at different temperatures. Molar ratios of H2O/ATB (from 1 to 25) and HCl/ATB (from 0.08 to 0.4) were changed for some other samples, during synthesizing process. The products were characterized by both XRD and FTIR measurements. Studies were carried out on the effect of calcination temperature and change of H2O/ATB and HCl/ATB ratios on structure and processes involved in phase transformations.DOI: http://dx.doi.org/10.5755/j01.ms.21.1.4872</p

Fuel effects on properties of alumina nanoparticles synthesized by combustion technique

Alumina nanopowders have been produced by solution combustion synthesis using aluminum nitrate as oxidizer and urea (U), ammonium acetate (AA) and ammonium nitrate (AN) as fuels. The fuel effects on properties of products have been studied. Enthalpy and adiabatic flame temperature are calculated theoretically for each fuel based on thermodynamic concept to determine its exothermicity. Thermogravimetric (TG) analysis has also been carried out to determine the thermal properties of the metal nitrate and fuels. The prepared samples have been characterized by X-ray diffraction (XRD), N2 adsorption (BET) and scanning electron microscopy (SEM). The results show that by reducing the exothermicity of reaction, alumina nanopowders with smaller crystallite size, finer agglomerate and higher specific surface area are produced

Preparation and Characterization of Zinc Oxide Nanoparticles Using Leaf Extract of Sambucus ebulus

Plants are one of the best sources to obtain a variety of natural surfactants in the field of green synthesizing material. Sambucus ebulus, which has unique natural properties, has been considered a promising material in traditional Asian medicine. In this context, zinc oxide nanoparticles (ZnO NPs) were prepared using S. ebulus leaf extract, and their physicochemical properties were investigated. X-ray diffraction (XRD) results revealed that the prepared ZnO NPs are highly crystalline, having a wurtzite crystal structure. The average crystallite size of prepared NPs was around 17 nm. Green synthesized NPs showed excellent absorption in the UV region as well as strong yellow-orange emission at room temperature. Prepared nanoparticles exhibited good antibacterial activity against various organisms and a passable photocatalytic degradation of methylene blue dye pollutants. The obtained results demonstrated that the biosynthesized ZnO NPs reveal interesting characteristics for various potential applications in the future