فهرست مطالب sara rahimnejad

CdS-coupled TiO2 nanocrystals were prepared by the microemulsion-mediated solvothermal method at pretty low temperatures. The semiconductor nanocrystals were modified with tyrosine, phenyl alanine, glysine and glutamate aminoacids and then were characterized by BET, SEM, EDX, XRD, UV–Vis spectroscopy, and FTIR analysis methods. The specific surface area and the average pore diameter were found to be about 470 m2 g−1 and 2.8 nm, respectively. Moreover, the average size of the CdS-TiO2 particles was evaluated to be 28 nm. The results showed that the modification process with the aminoacids improves the adsorption capability and photoactivity of the samples. Among them, tyrosine was determined to be the best choice. According to the results, modification of CdS-TiO2 heterojunction photocatalyst with electron-donating groups is an efficient strategy to increase the photoreduction of nitroaromatic compounds. Reusability experiments were also carried out and confirmed the high capacity of the prepared samples for the photoconversion of nitrobenzene after being repeated for four times.

In this research, TiO2 nanotubes were synthesized by anodized oxidation method and were covered with a hydroxyapatite-silver nanoparticles using photodeposition and dip coating for loading silver nanoparticles and coated hydroxyapatite (HA). The morphological texture of TiO2 nanotube and Ag-HA nanoparticles on TiO2 nanotubes surface were studied by field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDAX analysis) and X-ray diffraction (XRD). The MCF-7 cell lines were treated with concentrations 1, 10 and 100 µg/ml of TiO2 nanotubes and HA/Ag/TiO2 nanotube for 24 and 48h. Finally, the cell viability and IC50% were evaluated using MTT assay. The results show that the HA/Ag/TiO2 has more positive effect on enhancing the cell death compare to TiO2 nanotubes and also exerts a time and concentration-dependent inhibition effect on viability of MCF-7 cells

Nowadays، Dye sensitized solar cells (DSSCs) emerged as a new class of low cost solar cells that affordable to convert light energy into electrical energy and also they are known as the third generation of solar cells founded on nano structured thin films. Titanium dioxide usually plays as the semiconductor for transmission of excited electrons from dye to the counter electrode (cathode). During one cycle of electron transfer، which electrolyte plays an important role in the electron transportation، electrons will return to the excited dye molecules. This phenomenon practically presents the sunlight conversion into electricity by solar cells. In this project eggplant was used as a natural source of dye for fabrication of DSSC. Dye extraction was performed by suitable solvent and its purification was conducted by Solid Phase Extraction columns. The electrochemical evaluation and final efficiency measurement of fabricated cells were carried out by Electrochemical Impedance Spectroscopy method which is well known as a powerful and non destructive technique in studying of charge transfer on the surface of nano structured electrodes.