Inventor: Teacher Dr. Salma Mahdi Shaban/Department of Physics, College of Science, University of Baghdad
Abstract
Titanium foil (99.999%; thickness 0.25 mm) was cut into suitable shape for conductive brass in the base holder of a Teflon cell. The sample was liberated by sonication in a solution of acetone and ethanol for 15 min respectively, and then washed in (DI) deionized water, before anodizing, the titanium samples were annealed at 550 ºC for 3 h to remove the mechanical stress and to enhance the grain size, and then cooled in air. The titanium foil Ti surface was surface polished mechanicallywith glass papers starting from 240 and increasing to 400, 600, 800 and 1200 with diamond material. Intermittently after polishing with different sandpapers, the surface was washed with (DI) deionized water to rinse off any particles generated duringpolishing. Ultrasonic cleaning in acetone, ethanol and (DI) deionized water respectively for about 15 minutes was done after polishing to clean the surface more effectively then dried with (N2) nitrogen stream, after the mechanical polishing process is completed, sample put in Teflon cell and it is prepared to next electrochemical process. The samples were pressed together with a Cu plate against an O-ring in an electrochemical cell (1 cm2 exposed to the electrolyte) and anodized at 25 V in 1M H2SO4 electrolytes containing 0.16 M hydrofluoric acid (HF) for 3 h to grow a 600 nm thick TiO2 nanotube layer. After this, the nanotube layers were rinsed, dried and a second anodization step was performed in 0.09 M NH4F in deionized water and EG. The water concentration in the solution was 30vol% and the experimental voltage ranged 20, 30, 40, 50, 60 and 70 V for 4 h at room temperature. All electrolytes were prepared from reagent grade chemicals. NH4F acts as a pore opening reagent and the NH4F concentration also plays a key role in controlling the surface morphology, but we fixed it into 0.09 M in order to focus on the effects of the water concentration and applied voltage. The TiO2 nanotube arrays yielded were rinsed with de-ionized water and dried in air spontaneously after the experiments. ZnO production nanostructure using different method: first method, electrochemical deposition on Zn foil using 0.3 M zinc sulfate heptahydrate (ZnSO4.7H2O) and sulfuric acid aqueous solution at a current density of 30 and 35 mA/cm2 for deposition time 40 min at room temperature and second method, Zn foils were thermally oxidized in a conventional tube furnace at a temperature equal range of 700–900 _C in air for 5 h or less in static air to prepared semiconductor nanomaterials ZnO nanorods, nanotetrapods and nanoplane. The XRD diffraction of higher intensity peaks at (101) and (002) miller indices for two methods can be recognized to a hexagonal wurtzite structure unit cell. Surface morphology images with different magnifications which clearly shows that the whole Zn foil and rod substrate obtained ZnO nanosheets, nanotetrapods, nanorods and growth nanoplanes were also found. The length of these nanotetrapods and nanorods lies in the equal range of 1–1.5 μm with an average diameter of 80 nm. It was well known that ZnO nano crystal exhibited two emission peaks. One was located at about 365 nm wavelength (UV luminescence band), and the other peak position at 475 nm wavelength (green luminescence band). Metal oxide semiconductor nanocomposite prepared by using (Cu(NO3)2.3H2O (0.07 mol), Zn(NO3)2.6H2O (0.07mol) and SnCl2.2H2O (0.07 mol)) were initially dissolved in 250 ml of water, ethanol and HCl. Then urea (0.2 mol) was added to the homogeneous liqude and transferred into a Teflon lined stainless steel autoclave with a volume of 50 ml, the autoclave was sealed and kept at 180 C˚ for 10 hour on hot plate stirrer with slow stirring. After the complete reaction, it was cooled to 35°C (room temperature). The product was filtered, washed with water, acetone and dried at 120 °C in oven (hot air).Tin dioxide (SnO2) nanostructured thin films on quartz substrates were prepared by rapid thermal oxidation technique for different oxidation temperatures and oxidation times. X-ray diffraction analysis indicates that the films are polycrystalline, having tetragonal structure. All the films shown most preferred orientation along (101) plane parallel to the substrates. The nanostructure parameters such as grain size, microstrain and dislocation density were calculated. The grain size of prepared SnO2 nanostructure films is small and is within the range of 44 to 56 nm. The nanocomposite oxides (CuO-SnO2-ZnO) prepared to use hydrothermal method consist of small nanorod distributed on the surface that shows nanostructure properties.