جستجوی مقالات مرتبط با کلیدواژه « Electrochemical impedance spectroscopy » در نشریات گروه « مهندسی شیمی، نفت و پلیمر »

Zinc oxide nanostructures exhibit unique properties which make them suitable for dye-sensitized solar cell applications. Their specific properties such as appropriate optical properties, proper energy band gap and high electron transfer characteristics have motivated researchers to use them in the fabrication of dye-sensitized solar cell photo-anodes. In the present study, the effect of thickness on the performance of a new ZnO photo-anode has been studied. All the photovoltaic parameters of the cells fabricated using N719 ruthenium dye were measured. SEM technique was utilized to determine the thickness and the UV-Visible method was used to study the transparent properties of the photo-anodes. Electrochemical impedance spectroscopy technique was employed to determine the appropriate equivalent circuit for studying the electron transfer mechanisms in all the fabricated cells. The results demonstrated that the ZnO thickness is a critical parameter for providing either sufficient resistance to suppress the charge recombination process or appropriate electron transferring properties. The optimized ZnO photo-anode was obtained at a thickness of 19 µm, which resulted in an efficiency of 3.22%.

In this work, it was demonstrated that the anti-corrosion performance of the polypyrrole (PPy) coatings on mild steel can be affected by electrodeposition method, electrosynthesis solvent composition and ZnO nanoparticles concentration. Three different electrodeposition methods, namely, cyclic voltammetry, galvanostatic and potentiostatic techniques were empolyed. The anti-corrosion performance of the PPy coatings was investigated by electrochemical impedance spectroscopy. The PPy prepared by potentiostatic method exhibited the best performance against corrosion of mild steel in 3.5% NaCl solution. Then, different mixtures of H2O/ethanol were investigated as electrosynthesis solvents for the preparation of PPy coatings on mild steel via optimized electrodeposition mode (i.e. potentiostatic). Evaluation of the prepared coatings introduced the pure water as the optimum solvent for the PPy electrodeposition. Lastly, the investigation of different concentrations of ZnO nanoparticles proved that the PPy coating containing 0.025% ZnO nanoparticles was the best coating against the corrosion of mild steel in the NaCl solution.