This research project aims at the synthesis and characterization of nanostructured tungsten oxide (WO3) via ultrasound. A major advantage of ultrasound-assisted synthesis for nanostructures is the low amount of material used, because they are commonly needed a few milliliters of dilute solutions, another advantage that can be cited is the speed and ease of synthetic routes. The nanostructures are adsorbed on electrodes by electrophoretic deposition (EPD), which is very interesting method that provides direct contact of electroactive material with the electrode surface, thereby increasing the rate of electron transfer, in addition, by changing experimental parameters such as the electric field and deposition time, different architectures can be easily obtained. Electrodes modified by the structures of WO3 will be used to build-up electrochromic electrodes where high performance is due to surface immobilization of nanostructures by organic chromophores (bipyridine salts) that, in principle, confer a greater modulation of color to the electrode, taking into account that WO3 itself has excellent electrochromic properties that will be enhanced by the nano-structure. One possible application for the electrodes modified by WO3 is its use as optical sensors for gases, but this would be a theme to be developed for future collaborations. The characterization of nanostructures and their modified electrodes will be performed by various microscopic techniques such as High-resolution Transmission Electron Microscopy (HRTEM), Atomic Force Microscopy (AFM) and scanning electron microscopy (SEM). Different spectroscopic techniques are also used such as Electrochemical Impedance, Raman and Infrared. Obviously traditional electrochemical characterizations coupled with other in situ techniques , such as UV-Vis and the Quartz Crystal Electrochemical Microbalance . At last, it is worth noting the excellent facilities found in the Institute of Chemistry, University of São Paulo, where this project will be developped.
News published in Agência FAPESP Newsletter about the scholarship: