Vibrational Raman modes and particle size analysis of cupric oxide with calcination temperature

In this work a study of the effect of the synthesis conditions on the vibratory and particle size properties in the cupric oxide (CuO) has been presented. The synthesis has been carried out by the polymeric precursor method without modifying the PH in the process, this being a low cost method. The samples obtained have been subjected to several calcination temperatures, 450 °C, 550 °C, 650 °C and 800 °C. In particle analysis by X-ray, scanning electron microscopy (SEM) and statistical it has been observed that for very low or very high calcination temperatures the particle size increases, finding 650 °C as the best calcination temperature. In the Raman spectra, the Ag and Bg vibration have been presented in the samples, with the peaks being narrower for the temperature of 450 °C

Copper and iron oxide films deposited in Titanium Nanotubes

A tubular TiO2 / Ti matrix obtained by the electrochemical anodization method was used as a substrate for the deposit of a single litter of CuO (copper oxide) or CuO doped with 1% Fe by the spin coating method. In the anodizing methods two different times of 40 and 60 minutes were used respectively. In obtaining the anatase structure of TiO2, the samples obtained by anodization were calcined at 450 ° C and subsequently the copper oxide layer was deposited. In this study the structural properties were investigated by means of morphological x-rays by SEM measurements and optical properties through UV-Vis, Auger and Raman spectroscopy. In the X-ray measurements, the anatase phase is observed with secondary phases corresponding to the CuO. In SEM the uniform coating is observed for the method sample 2 to 60 minutes with CuO / Fe. In the measurements of Raman spectroscopy after calcination of the samples, the vibrational modes of TiO2 are obtained. In the Auger measurements, they indicated the presence of titanium in the Auger (L2M2,3M2,3) and (L2M2,3M4,5) transitions, located at 387eV and 418eV as well as Fe, O, C. Finally, our results suggest that TiO2 support -nanotubes / Ti with a CuO tank is promising for possible applications such as electrode.Una matriz tubular de TiO2/Ti obtenida por el método de anodización electroquímica fue usada como sustrato para el depósito de una única camada de CuO (oxido de cobre) o CuO dopado con Fe al 1% por el método de spin coating. En los métodos de anodizado se usaron dos tiempos diferentes de 40 y 60 minutos respectivamente. En la obtención de la estructura anatasa del TiO2 las muestras obtenidas por anodización se calcinaron a 450°C y posteriormente se depositó la camada de óxido de cobre. En este estudio se investigó las propiedades estructurales por medio de rayos x morfológicas por medidas MEB y propiedades ópticas a través de las medidas UV-Vis, espectroscopía Auger y Raman. En las medidas de Rayos x se observa la fase anatasa con fases secundarias correspondientes al CuO. En MEB el recubrimiento uniforme se observa para la muestra del método 2 a 60 minutos con CuO/Fe. En las medidas de espectroscopia Raman después de la calcinación de las muestras se obtienen los modos vibracionales del TiO2 . Las medidas Auger indicaron la presencia de titanio en las transiciones Auger (L2M2,3M2,3) y (L2M2,3M4,5) localizadas en 387eV y 418eV así como Fe, O, C. Finalmente nuestros resultados sugieren que el soporte TiO2nanotubos/Ti con un depósito de CuO es prometedor para posibles aplicaciones como electrodo

Influence of the H2O content and the time on the formation of nanostructures in a chemical solution of H2O/HF/NH4F/EG

The influence of anodizing time on the length, morphology and photoelectrochem-ical properties of TiO2 Nanotubes has been investigated. An optimum anodizing time of 20 min at 20V leads to 220nm long of the nanotubes. By having a detailed control of the electric current one can know exactly the time in which the nanotubes grew and the time in which the process stopped. The FEG-SEM measures show the morphology of the nanotubes and how they come to separate and fall after a certain time. However, the growth of these, is uniform with little remaining material on the surface. For the solution of the anodizing process it is very important to control the amount of water, ethylene glycol and hydrofluoric acid. Small modifications in the solution change the growth time and size of the nanotubes

Resistive state of a thin superconducting strip with an engineered central defect

We study the resistive state of a mesoscopic superconducting strip with an engineered defect at the center. The defect is another superconductor with a different critical temperature. Several geometrical shapes of the defect are studied. The strip is considered under a transport electrical current, Ja, and at zero external applied magnetic field. The current is applied through a metallic contact, and the defect is simulated with the phenomenological parameter α(T) = α0(T − Tc(r)) in the Ginzburg-Landau free energy density. Here Tc(r) = Tc,0 + δT(r), where δT(r) 0) corresponds to a domain of lower (higher) critical temperature. It is shown that the critical current density for the I–V characteristic curve, Jc1, at which the first vortex-antivortex (V-Av) pair nucleates in the sample, as well as its dynamics, strongly depend on the critical temperature, the position, and the geometry of the defect

Tower as magnetic antipinning core in a small superconducting sample

Using the nonlinear Ginzburg-Landau equations we study the vortex configurations in a superconducting square with a central square pillar in the presence of a uniform applied magnetic field. The presence of the pillar changes the vortex structure in the superconducting sample considerably. We calculate magnetization, magnetic induction, supercurrent and vorticity, which show different vortex configurations as a function of magnetic field. (C) 2014 Elsevier B.V. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Synthesis and Structural Properties of Niobium Pentoxide Powders: A Comparative Study of the Growth Process

Powders Nb2 O5 were prepared by two different synthesis method, Sol-Gel and polymeric precursors (Pechini). In the Pechini method before adding the citric acid in the process, four different solutions were used to get the samples. For Sol-gel method, two different processes were also used in obtaining powders. The precursor was completely solubilized in ethanol and then hydrolyzed with ammonia and water. The calcination of the samples was between 500 and 750°C. The resulting powders were characterized by Scanning Electron Microscopy (SEM), Brunauer, Emmett and Teller (BET) surface area measurements, UV-visible and Raman spectroscopy. The formation of T−Nb2 O5 orthorhombic took place upon calcination at 7500C. Crystallite sizes were determined using the Scherrer method which resulted in an uniformed size of about 25 − 65nm. Ultraviolet-Visible diffuse reflectance spectroscopy indicated a variation in the optical band gap values (3.32-3.40 eV) in crystal growth process. The Raman vibrational modes indicate the presence of the orthorhombic phase of the material

Efectos estructurales en el semiconductor insb, por la aplicación de diferentes métodos de presión

This paper studies the modifications suffered by the Indium Antimonnide (InSb), grown in the [100], when subjected to mechanical tests of micro-indentations, high hydrostatic pressure and pressure impact. Tomographic surveying and samples were made by micro-Raman spectroscopy with different wavelengths of excitation light. The shift of the position of the phonons and the emergence of new Raman peaks allow both chemical and structural analysis of the systemEn este trabajo se estudia las modificaciones sufridas por el Antimoneto de Indio (InSb), crecido en la dirección [100], cuando es sometido a testes de micro-indentación mecánica, altas presiones hidrostáticas y presión por impacto. Los estudios topográficos y tomográficos de las muestras fueron hechos por medio de espectroscopia micro-Raman con diferentes longitudes de onda de la luz de excitación. El corrimiento de la posición de los fonones y el surgimiento de nuevos picos Raman permite el análisis tanto químico como estructural del sistema en estudi

Enhancing Co₃O₄ nanoparticles: Investigating the impact of nickel doping and high-temperature annealing on NiCo₂O₄/CoO heterostructures

In this study, we investigated the phase transition of cobalt spinel (Co3O4) nanoparticles into Co3-xNixO4/CoO heterostructures by introducing varying amounts of nickel (x = 0.0–0.16) and subjecting the particles to high annealing temperatures of 1000 ℃. X-ray diffraction (XRD) analysis confirmed the Co3-xNixO4CoO structure for all samples. Transmission electron microscopy (TEM) provided further insights into the phase or heterostructure of the samples after annealing, revealing the arrangement of the two phases. Fourier-transform infrared spectroscopy measurements demonstrated a band shift around 537 cm-1 with increasing Ni content, while ultraviolet-visible (UV-Vis) measurements indicated the energy band (Eg). Significant morphological changes were observed in scanning electron microscope (SEM) measurements at 0.16 Ni, displaying irregular agglomerates. Our findings suggest that introducing Ni into the Co3O4 structure and increasing the annealing temperature to 1000 ℃ can lead to the formation of a heterostructured system. Furthermore, our study's significance is highlighted by the streamlined synthesis of NiCo2O4/CoO using the sol-gel method followed by calcination. This departure from complex techniques provides an efficient route to acquiring the NiCo2O4/CoO system, a promissory material for advancing supercapacitor research