6 research outputs found
Characterization of Ag-TiO₂ Powders Prepared by Sol-Gel Process
In this study, microstructure and electrical properties of Ag-TiO₂ powders, which were prepared by a simple sol-gel method, are investigated. The sol was prepared from titanium iso-propoxide, Ti(OC₃H₇)₄ in iso-propanol (CH₃CHOHCH₃), used as solvent. AgNO₃ was used as the precursor for Ag. For the structural studies, the corresponding gels were allowed to dry naturally for about seven days, dried in an oven at 180°C for 30 min and then calcined at different temperatures (900, 1000 and 1100°C). The Ag-TiO₂ nanoparticles were characterized using differential thermal analysis/thermal gravimetry, scanning electron microscopy, energy-dispersive X-ray analysis and X-ray diffraction. The results X-ray diffraction indicate that pure Ag and TiO₂ powders are in rutile phase. However, calcination temperature had not significantly affected the crystalline structure of TiO₂. Scanning electron microscopy images of powders show an aggregation of small spherical particles of dispersed sizes. Annealing of the Ag-TiO₂ sample at high temperature produced more spherical particles, which aggregated to form bigger particles with porous structures. The electrical properties of the samples were measured using HMS-3000 Hall measurement system. The samples were found to be of n-type. The conductivity of TiO₂ samples have been explicitly increasing with calcination temperature and with Ag doping