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There is increasing interest in the synthesis, characterization and application of mixed oxides for better functional performance compared to base metal oxides. In this study, Zn0.95-xCu0.05CoxO (0 = x = 0.05) nanocomposites were synthesized by co-precipitation method. The synthesized samples were characterized for its structural, compositional and optical properties using by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-ray Photoelectron Spectroscopy (XPS), Raman spectroscopy and UV-Vis absorption spectroscopy. According to XRD results, it is seen that the würtzite structure of hexagonal ZnO does not change. In addition, it can be said that the separate phases of Cu2O and Co3O4 are formed due to the unreacted parts of Cu+ and Co+3 ions. This is also confirmed by XPS results. The average crystallite size of the Zn0.95-xCu0.05CoxO nanocomposites were found in the range of 30.02-22.00 nm. It is seen that the crystal growth decreases as a result of Cu and Co doping in ZnO. SEM images show that all samples are composed of spherical nanoparticles. EDS spectra confirms the presence of Zn, Cu, Co, and O atoms in the samples with expected stoichiometry. As the Co concentration increases from x=0.00 to x= 0.05, the band gap increases from 3.26 eV to 3.57 eV. [ABSTRACT FROM AUTHOR]

In this study, the structural and magnetic properties of permalloy thin films with thicknesses varying from 4 to 20 nm on Si (100) / SiO2 (~ 200 nm) substrate were investigated. Permalloy thin films were prepared in a high vacuum chamber using the oblique angle magnetron sputtering technique. From the in-situ X-ray photoelectron spectroscopy measurements, the alloy composition ratio of permalloy was found as 21% Fe and 79% Ni. X-ray diffraction and reflectivity measurements showed that permalloy films grew in (111) orientation with low surface roughness and at the nominal thicknesses. Magnetic properties were investigated using ferromagnetic resonance (FMR) and vibrating sample magnetometry (VSM) techniques. In-plane uniaxial magnetic anisotropy was observed in the films due to the oblique deposition used in film preparation. Experimental FMR data were simulated by writing a computer code using the free energy minimization method according to the magnetization direction, and thus these uniaxial anisotropy constants of the films were determined. In addition, variations of magnetic properties such as coercive field and anisotropy field depending on thickness are discussed. [ABSTRACT FROM AUTHOR]

In this study; a flexible, self-contained and durable PtCu/reduced graphene oxide (iGrO) hybrid paper was synthesized and used for the electrochemical detection of p-nitrophenol (PNP). PtCu/iGrO hybrid paper was fabricated through electrodeposition of PtCu composite structure on iGrO paper electrode. The obtained PtCu/iGrO hybrid paper was characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, electrochemical impedance spectroscopy. The morphological analysis of PtCu/iGrO hybrid paper showed that flower-like nanostructures formed on the iGrO electrode surface consist of numerous sharp-edged nano layer of PtCu. PtCu/iGrO hybrid paper electrode demonstrated high electrocatalytic performance compared to iGrO paper and exhibited a wide linear range (0.08-760 μM) and a low detection limit (0.022 μM) for the determination of PNP. The PtCu/iGrO hybrid paper sensor also showed high recovery values for PNP detection in tap water. The hybrid paper sensor prepared with a practical and easy-to-apply method exhibited mechanically flexible and durable properties. Moreover, stability tests of PtCu/iGrO paper displayed that this hybrid electrode is an important candidate for high-performance flexible sensor applications. [ABSTRACT FROM AUTHOR]

In this study, a new route was proposed for electrochemical synthesizing of TiO2 doped diamond-like carbon (DLC) nanocomposite film. To obtain TiO2 doped DLC nanocomposite film, firstly, titanium metal was dissolved in hydrogen peroxide (H2O2). Then, the obtained solution and methanol were mixed with the volume ratio of 1:200 and electrolyzed in a two-electrode cell. The obtained film was characterized by scanning electron microscope (SEM), Raman spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction. SEM image showed homogeneous and porous film. Raman spectroscopy indicated that TiO2 doping leads to sp3 hybridized carbon bonds. XPS analysis confirm TiO2 doping and sp3 bonds. In the XRD spectrum, the observed peaks attributed to hexagonal carbon structure. The obtained results show that DLC nanocomposite film containing high amounts of sp3 bonds can be successfully produced by the electrochemical method. [ABSTRACT FROM AUTHOR]

The flexible, free-standing and durable highly rough NiS/rGO composite paper electrode was prepared with a simple electrochemical deposition of NiS structures on the surface of the rGO paper electrode. NiS/rGO composite paper electrode was characterized by using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Xray diffraction (XRD), Raman spectroscopy and electrochemical impedance spectroscopy (EIS) techniques. Asprepared NiS/rGO composite paper was used for the electrochemical detection of ascorbic acid (AA). The rough and the ball-like NiS nanostructures on the rGO paper electrode surface greatly increased the catalytic performance of the paper electrode by providing a large active surface area. AA was detected on NiS/rGO composite paper with a wide linear range from 1.0 to 800 μM, a low detection limit of 0.7 μM (S/N=3) and a high sensitivity. Besides, the electrochemical tests showed that the composite paper electrode is very stable, flexible and durable at the atmospheric conditions. [ABSTRACT FROM AUTHOR]

In this study, free-standing MnO2 coated reduced graphene oxide (MnO2/rGO) paper with high flexibility and durability was prepared. As-prepared MnO2/rGO paper was characterized by scanning electron microscopy-energy-dispersive Xray spectroscopy (SEM-EDS), X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The electrochemical behavior of dopamine (DA) was investigated on flexible MnO2/rGO paper with cyclic voltammetry and amperometry methods. Electrochemical results have shown that the flexible MnO2/rGO paper electrode exhibits excellent electrocatalytic activity to DA due to its high specific surface area. In addition, the obtained flexible electrochemical sensor showed a wide linear range, a low detection limit and a very sensitive response for the amperometric determination of DA. [ABSTRACT FROM AUTHOR]

Nanocrystalline cobalt ferrite (CoFe2O4) has been synthesized directly from metallic cobalt (Co) and iron (Fe) via wet-milling followed by calcination. The calcination took place in atmosphere at 750 °C. After calcination, samples were dry-milled for up to 12 h to investigate the effects of their mean crystallite sizes and microstress on their magnetic properties. The mean crystallite sizes of the samples were calculated from X-ray powder diffraction (XRD) patterns using a Rietveld analysis program (MaudLab). Results show that the calcined sample had a crystallite size of around 60 nm, which decreased to 12 nm after 12 h of drymilling. However, agglomerated nanocrystallites were observed in the transmission electron microscopy (TEM) images of the material. Rietveld analysis also shows an increase in microstrain from 2 x 10-4 to 1.4 x 10-3 after increasing the dry-milling time to 12 h due to crystal defects induced by collisions while drymilling. The electron binding energies of the Co+2 were measured by X-ray photoelectron spectroscopy (XPS) to determine the degree of inversion, which was used to calculate the saturation magnetization. Vibrating sample magnetometer (VSM) measurements revealed that milling decreased the saturation magnetization from 125 emu g-1 to 57 emu g-1 even the calculated saturation magnetization increased from 4.87 µB to 6.17 µB. [ABSTRACT FROM AUTHOR]

In order to combine the antimicrobial effect of silver with mechanical and chemical properties of titanium nitrate, Ag was deposited on the surface of Ti6Al4V (orthopedic implant material) in N2 plasma by using plasma immersion ion implantation and deposition (PIII&D) method. The coatings were formed by using varied negative pulsed high voltage and magnetron sputtering voltage values of PIII&D process. Surface morphologies of coatings were determined with atomic force microscopy (AFM), while cross-section morphologies were determined with field emission scanning electron microscopy (FE-SEM). The phases and chemical compositions of coatings were investigated by using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. XPS depth profile analysis were done to reveal the penetration of Ag+ ions into the surface of specimen. In in vitro anti-bacterial effectiveness experiments, the adhesion of E. coli (Escherichia coli) microorganism, which were marked with 99mTc radioisotope, on surfaces of specimens was investigated. It was consequently determined that Ag was dominant in the coatings obtained by applying 8 kV negative pulsed high voltage, while Ag decreased on the surface depending on the increase in the voltage. [ABSTRACT FROM AUTHOR]