Synthesis and characterization of nanomaterials for photocatalytic applications
مؤلف
Al-Hinaiyah, Muna Hamed Salim
الملخص الإنجليزي
The thermodynamic data for the stability of ZnSnO3 in aqueous media was calculated as a function of pH and potential (Eh). The obtained was overlapped on the Pourbaix diagram of Zn-H2O system at 25 °C to construct a new Pourbaix diagram of Zn-Sn-H2O system at 25 °C. The new Pourbaix diagram will be useful to determine the pH and potential stability area of ZnSnO3 which can be used to synthesize the material at low temperature at a known reactants concentration. The produced ZnSnOz was characterized using X-ray diffraction, Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy (SEM). The obtained powder was indexed to ZnSnOz in JCPDS (11-0247). The particle size and shape was studied at different reactants concentration and synthesis temperature. The particle size was determined from SEM micrographs of the samples and it was in micron size (ranging from 0.7 to 5 um). The crystallite size was in nanoscale. Photocatalytic activity of the ZnSnOz samples was tested using organic dyes. The concentration of the dye was determined with time to compare the photocatalytic activity of ZnSnOz samples. To enhance photocatalytic activity, ZnSnO3 was doped with 5% Mn(II) and a sample of the doped ZnSnOz was annealed at 400 °C. The photocatalytic activity of the Mn(II) doped sample after annealing was the best. A new synthesis route for the preparation of TiO2 at low temperature was designed using Pourbaix diagram of Ti-H20 system. Different synthesis temperatures were used to study the effect of synthesis temperature on the obtained TiO2 phase anatase or rutile phase. The effect of Fe(III) doping of TiO2 was studied at different doping percent. The structure of the rutile TiO2 and Fe(III) doped TiO2 samples was analyzed with transmission electron microscope which shows the formation of TiO2 nanotubes.
