Development of nanostructured metal oxide electrodes for converting solar energy into chemical energy: Solar fuels
The focus of this proposal is to produce active nanoscale materials for application in devices capable of converting and storing solar energy into chemical energy. For this, it is proposed the synthesis and characterization of pure iron oxide electrodes (abundant mineral) and modified by the deposition of different modifier elements such as Sb and Zr. In this proposal, the materials will have as main focus the application in a device for converting solar energy into chemical energy through photoelectrolysis reactions in the presence of water (generating H2 and O2 gas as products). Electrodes with different morphologies (eg, spheres or rods) of iron oxide will be wet synthesized, with emphasis on the process involving the preparation of an aqueous solution of the precursors kept in hydrothermal conditions at constant temperature (100 °C or 120 ° Ç). This methodology was chosen due to the absence of complexity (sophisticated apparatus), easy thickness control, and scaling for the industry. The success of the developed materials will be evaluated regarding the gain in the efficiency of the conversion of solar energy into oxygen and hydrogen during the process of sunlight-induced water electrolysis, electrochemical impedance spectroscopy (simulating the application environment, in the dark and under lighting ) which allows investigating the charge transport between the interfaces (substrate-semiconductor layer and conductive layer-electrolyte), in a complementary way, the charge transport dynamics at the interface will be evaluated by transient absorption spectroscopy; the processes and transformations on the surface during operation will be monitored by photospectroelectrochemistry, in addition to X-ray diffraction and Raman techniques.